20 Gallon Tank Raising pH naturally in 20g

I am wanting to find a way to naturally raise the pH in my aquarium. I raised it temporarily using baking soda simply for the cycling process but I am aware that after a certain amount of water changes the original pH will return. I cycled the tank at the pH of 8.2 and my tank is usually 6.6, so I want to find a natural way to constantly increase it to about 7-7.5. I have read online that you can use things like crushed coral and dolomite chips and was wondering what would be best.
1) Can you use both of these safely in a freshwater tank without any issues and side-effects?
2) Will they effectively raise the pH and keep it stable?
3) Will they dramatically affect GH and KH to the point where my fish will be affected? BTW I don't have a test kit for GH and KH.
I will be keeping Honey Gourami, Neon Tetras, Harlequin Rasboras, Corydoras, and Otos and am aware that some of these prefer slightly acidic however I don't want to increase it dramatically, just slightly, and most importantly, I want to keep it stable and constant. Will this work and will it be safe? How would you recommend I administer it to keep it at a pH of around 7-7.5? Thanks.

 

1) Can you use both of these safely in a freshwater tank without any issues and side-effects?

Issue: It will harden the water until saturation.

2) Will they effectively raise the pH and keep it stable?

See 1. Yes, but higher than you are aiming for.

3) Will they dramatically affect GH and KH to the point where my fish will be affected? BTW I don't have a test kit for GH and KH.

See 1. Edit: Get that test kit for GH/KH. Whenever you want to change anything about pH and hardness it is VITAL to know these. No matter if you want up or down.

I will be keeping Honey Gourami, Neon Tetras, Harlequin Rasboras, Corydoras, and Otos and am aware that some of these prefer slightly acidic however I don't want to increase it dramatically, just slightly, and most importantly, I want to keep it stable and constant.

You said you usually have a 6.6 pH (which implies low KH and GH aswell). You already know your fish would do great. Why ruin this? Low pH does NOT mean automatically unstable. Just low. That's all. If you absolutely want to be safe add some humic subtances ("tannins"). They buffer in lower pH-ranges. Just as stable as the other method, closer to your fishes needs and even less work. (Add leaf litter. Done.) And cheaper. Next fall leaf litter will be available for free everywhere.

Will this work and will it be safe?

Yes.

How would you recommend I administer it to keep it at a pH of around 7-7.5?

See 1. The water will take up buffering minerals until saturated. This will end you in the GH/KH 10-15° range, with a pH in the low 8s.

 

Thanks so much for the response, advice, and info. Yes, the environment in my tank is ideal for the fish and I see what you mean. I have a large piece of driftwood and PLENTY of tannins. The only thing is, I raised it to 8.2 with baking soda for the bacteria to get the cycle started ( I heard that the bacteria is dormant under a pH of 7), which it has, but after a few water changes the original pH will be restored and I have heard that you should cycle at the pH you want long term. Apparently the bacteria or 'nitrifiers' I have grown under this pH will not necessarily work under a pH of 6.6 and the nitrifiers that would have worked under this low pH have not colonised because it was not cycled under this pH. Does this make any sense? From what I understand, if I let the tank go back to this pH after it is finished cycling and add my fish, there are actually no nitrifiers under this pH? The I am technically starting the cycle all over again? Am I complicating this too much? Should I just let my cycle finish (it is almost handling 2ppm Ammonia in 24 hours) under the current pH of 8.2, do a large water change to lower the pH, add some fish and see what happens?

 

From what I understand, if I let the tank go back to this pH after it is finished cycling and add my fish, there are actually no nitrifiers under this pH? The I am technically starting the cycle all over again? Am I complicating this too much? Should I just let my cycle finish (it is almost handling 2ppm Ammonia in 24 hours) under the current pH of 8.2, do a large water change to lower the pH, add some fish and see what happens?

This I can contribute something to lol. XD

My recommendation is to lower the pH to what it should be (a 100% water change is fine, no need for a slow decrease) and continue the cycle. So long as ammonia and nitrite continues to be processed, at least you know the nitrifiers you currently have can still function (even if slower than before), and it'd just be a matter of continuing the cycle and making changes (like adding more biomedia) if necessary. If ammonia and nitrite oxidation completely stalls, then you know your current nitrifiers are not suitable, and best to try and introduce something that can work at the pH (rather than introducing fish right away).

 

The only thing is, I raised it to 8.2 with baking soda for the bacteria to get the cycle started ( I heard that the bacteria is dormant under a pH of 7), which it has, but after a few water changes the original pH will be restored and I have heard that you should cycle at the pH you want long term. Apparently the bacteria or 'nitrifiers' I have grown under this pH will not necessarily work under a pH of 6.6 and the nitrifiers that would have worked under this low pH have not colonised because it was not cycled under this pH. Does this make any sense?

It is easy to follow. Your "mistake" was to raise pH in the first place (and with baking soda). I'd not even call it a mistake. Simply the action that set you back.

From what I understand, if I let the tank go back to this pH after it is finished cycling and add my fish, there are actually no nitrifiers under this pH? The I am technically starting the cycle all over again? Am I complicating this too much? Should I just let my cycle finish (it is almost handling 2ppm Ammonia in 24 hours) under the current pH of 8.2, do a large water change to lower the pH,

If you want longterm success, minimum work and the least future problems:
Bring the parameters back to the original levels (pH 6.6 etc.) and let it cycle there. If you're lucky the nitrification hasn't stopped completely (which should be the case actually) and you're through the roughs in a few weeks.

add some fish and see what happens?

No. That would get you in a fish-in cycle, which is stressful for you and potentially dangerous to the fish, unless you have done this before (and as most people get into a fish-in cycling by accident and not on purpose, just don't do it.)

Patience is your best friend now.

Your decision to raise pH has set you back. That's a fact, that's what you have to deal with now. Now, after bringing levels down again, all it takes is time. That is really all. Being pro-active now can topple the whole project over. You've got driftwood in already, add leaf litter and botanicals, the biofilms on all that stuff will help get biological stability in a few weeks the tank can be stocked (lightly!).

 

Ok, thanks again so much for the response
I did a 100% water change today and after a few hours tested a pH of 6.8-7 (pure water).
Hopefully in the next few days the pH will reach the 6.6 with the driftwood in there. I was actually advised on another forum to raise the pH just for the purpose of cycling the tank. Lesson learnt. I tested the pH this morning (before my 100% WC and about 10 days after I raised the pH, and it was 7.6! I'm thinking it's the drift wood). I will now let the driftwood do its thing and bring the pH down and I already have plants in there. I have seeded the tank with multiple pieces of filter media over the time it has been cycling. I have just dosed the tank again with 2ppm to feed the bacteria (it is currently pH 6.8-7.0). Should I just continue dosing my ammonia to 2ppm every day, allow the pH to decrease slowly to it's natural level over the next couple of days, and wait for the cycle to finish? I know this is a difficult question to ask, but how long would you estimate would the cycle take from this point? I just want a rough idea so that I know I'm on the right track... Right now I am dosing 2ppm daily, and 24 hours later I test and get:
Ammonia: 0ppm
Nitrite: 2ppm
Nitrate: 5ppm

 

and wait for the cycle to finish?

Yes, as long as it takes.

I know this is a difficult question to ask, but how long would you estimate would the cycle take from this point?

Indeed a hard question to answer. I estimate, with seeded media and keeping that media fed... 2 weeks, give or take 1 week. Keep testing. When the ammonia you add is turned into Nitrates in less than 24 hours and you don't get readings for Nitrites anymore, you can add fish. That part is universal no matter what parameters.

 

I have just dosed the tank again with 2ppm to feed the bacteria (it is currently pH 6.8-7.0). Should I just continue dosing my ammonia to 2ppm every day, allow the pH to decrease slowly to it's natural level over the next couple of days, and wait for the cycle to finish? I know this is a difficult question to ask, but how long would you estimate would the cycle take from this point? I just want a rough idea so that I know I'm on the right track... Right now I am dosing 2ppm daily, and 24 hours later I test and get:
Ammonia: 0ppm
Nitrite: 2ppm
Nitrate: 5ppm

Chances are your 2ppm nitrite is more like 5ppm, or even more likely, off the charts. You can do a serial dilution to guesstimate where it may be at.

But anyways, you should only re-dose ammonia when both ammonia and nitrite reaches zero. Otherwise you run the risk of having nitrite just climb super high each time, causing multiple issues - being so high it stalls the cycle, not being able to track the cycle, and prolonging the cycle due to more nitrite oxidizers than necessary having to grow.

 

Yeah, the Nitrite is bright, dark pink-purple, which doesn't quite match the 2ppm nor the 5ppm. Is it really that high? I read that you should redose every time NH3 hits 0ppm because you are feeding the first group of bacteria still. Oh well. I'll carry on doing partial water changes until Nitrite really does show something on the chart. But how is it possible that after my 100% water change yesterday, nitrite was still 2-5ppm+?
So it's the next day after my 100% water change, and the pH has stabilised back to the 6.6 - yay!
At least I know it's on the pH it should be. However, I am having issues with the Nitrite. I just tested using two test kits, (last night I still dosed Ammonia to 2ppm), and they each show a different reading. The newer test kit shows that bright pink (photos attached) which doesn't seem to match any colour and makes me think it's off the charts. The older test kit (not expired, just older) shows that it is about 1.0-2.0ppm (photos attached). I thought that one of them is wrong and must have been damaged in some way, so I decided to test it against a control. I have a 5.5g that has been fully established and healthy for almost three years now with great water parameters. I tested the Nitrite in that one with both and figured that if they were correct, they should both show 0ppm Nitrite. Sure enough, they both showed a bright, light blue indicating 0ppm Nitrite with confirms that the test kits are not faulty. Why then am I seeing conflicting results for the Nitrite in my cycling tank?

 

Yeah, the Nitrite is bright, dark pink-purple, which doesn't quite match the 2ppm nor the 5ppm. Is it really that high? I read that you should redose every time NH3 hits 0ppm because you are feeding the first group of bacteria still.

You don't need to keep on feeding the first group of nitrifiers, they are fine to be left alone. If they have yet grown to a point where they can handle 2ppm ammonia/day, they will anyways as you continue to grow the second group. If they have, well then they don't need to grow any further. Either way they do not need to be fed constantly. They can go ammonia-starved for prolonged durations. Weeks, if not months or more.

Oh well. I'll carry on doing partial water changes until Nitrite really does show something on the chart. But how is it possible that after my 100% water change yesterday, nitrite was still 2-5ppm+?

Just to clarify, you did dose 2ppm ammonia yesterday after the water change right?

So it's the next day after my 100% water change, and the pH has stabilised back to the 6.6 - yay!
At least I know it's on the pH it should be.

That's awesome.

However, I am having issues with the Nitrite. I just tested using two test kits, (last night I still dosed Ammonia to 2ppm), and they each show a different reading. The newer test kit shows that bright pink (photos attached) which doesn't seem to match any colour and makes me think it's off the charts. The older test kit (not expired, just older) shows that it is about 1.0-2.0ppm (photos attached). I thought that one of them is wrong and must have been damaged in some way, so I decided to test it against a control. I have a 5.5g that has been fully established and healthy for almost three years now with great water parameters. I tested the Nitrite in that one with both and figured that if they were correct, they should both show 0ppm Nitrite. Sure enough, they both showed a bright, light blue indicating 0ppm Nitrite with confirms that the test kits are not faulty. Why then am I seeing conflicting results for the Nitrite in my cycling tank?

This can be due to differences in how much of the reagent is left in the bottle. Usually zero will keep a particular color no matter how much is left (more or less), but differences in amounts of reagents cause higher readings to differ.

Personally I have always had difficulties myself differing nitrite readings above 1ppm. >_> The color differences just is not obvious to me. >_<"

 

Just to clarify, you did dose 2ppm ammonia yesterday after the water change right?

Yes, but only after I tested Nitrite which was still 2-5ppm+ despite the full WC.

This can be due to differences in how much of the reagent is left in the bottle. Usually zero will keep a particular color no matter how much is left (more or less), but differences in amounts of reagents cause higher readings to differ.

Personally I have always had difficulties myself differing nitrite readings above 1ppm. >_> The color differences just is not obvious to me. >_<"

So should I assume it's one over the other and trust one kit's reading over the other? Should I just do partial water changes until both read lower readings? Do I do any WCs now and how many/how long between each one? And finally, do I really not dose anymore ammonia at all until Nitrite reaches 0 - at the rate I'm going that will be forever!?!?! What do I do nextttt...
Thanks so much, Azedenkae for the helpful responses and I appreciate your patience with me.

 

Yes, but only after I tested Nitrite which was still 2-5ppm+ despite the full WC.

That is... so weird.

So should I assume it's one over the other and trust one kit's reading over the other?

I am more inclined to trust the newer kit.

Should I just do partial water changes until both read lower readings? Do I do any WCs now and how many/how long between each one?

I would first suggest testing the nitrite in your tap water and make sure it is not nitrite in it that is causing the readings in your tank. Unless you already did, in which case apologies my reading comprehension is not at its best right now. XD

And finally, do I really not dose anymore ammonia at all until Nitrite reaches 0 - at the rate I'm going that will be forever!?!?! What do I do nextttt...

Yeah you really do not need to re-dose ammonia until nitrite reads zero. Don't worry, we'll figure it out. Not re-dosing will help us determine the cause.

We are actually following along another member who also struggled with nitrite: Latest attempts to get the N cycle going, with details | Aquarium Nitrogen Cycle Forum | 514722. Thanks to stopping re-dosing ammonia, we are finally really starting to get to the bottom of what may be wrong with his/her/their system.

Thanks so much, Azedenkae for the helpful responses and I appreciate your patience with me.

You're welcome. But yeah nah, let's test the water in your water source first.

If that's zero as well, then it is possible nitrite was so high that even a 100% water change still resulted in some left. Which is possible because 100% water changes are almost never 100% water changes after all. :3 Even with a few % left, if nitrite is high enough originally, we'd still see plenty after the water change.

 

Ok, tap water results are 0ppm. You must be right then - there was still enough left in the '100% WC' to still show up. My patience is testing me especially with the 100% WC making my tank look so beautiful and I'm itching for fish. However, I will not let that get the better of me! The test kits agree on everything else except the Nitrite as the pics showed. I did add liquid fertiliser directly after the WC - could this at all contribute to the Nitrite readings? I know it will for the Nitrates but how about the Nitrite? What should I do now?

 

Ok, tap water results are 0ppm. You must be right then - there was still enough left in the '100% WC' to still show up. My patience is testing me especially with the 100% WC making my tank look so beautiful and I'm itching for fish. However, I will not let that get the better of me! The test kits agree on everything else except the Nitrite as the pics showed. I did add liquid fertiliser directly after the WC - could this at all contribute to the Nitrite readings? I know it will for the Nitrates but how about the Nitrite? What should I do now?

I mean, fish-in cycling is always an option lol. XD

In terms of your liquid fert question though, unfortunately I do not know the answer to this. I don't use fertilizers in my tanks so can't say I've done enough research to tell you what would or may occur.

 

My patience is testing me especially with the 100% WC making my tank look so beautiful and I'm itching for fish. However, I will not let that get the better of me!

You can do it!

I did add liquid fertiliser directly after the WC - could this at all contribute to the Nitrite readings?

Some fertilizers contain Ammonium, so it is very well possible it contributed. Remember, it's Ammonia/-uim -> Nitrites -> Nitrates. So you got Ammonia-Oxydizing bacteria, that turn those into Nitrites. That's the first step working.

Btw, what substrate are you using?

 

I'm using a 3.5kg bag of Seachem Flourite spread thinly across the bottom of my 20g high and then about 2 inches of inert natural riverstone pebble gravel. About 3 weeks ago I also planted about 6-8 (I can't remember) of DIY root tabs which might have been disturbed with one of these water changes. I tried placing them as deep in as possible and I did use controlled release fertiliser to try and avoid an ammonia spike. I have done two more 50% water changes over the last two days, after the first one there was STILL the bright pink reading indicating it was still of the charts. It hadn't changed at all. However, after yesterday's 50% WC the colour was a very light lilac-indigo, that still didn't completely match any colour on the chart but seemed to be inbetween 0-0.25. I dosed with another 2ppm Ammonia, and after further research I have decided that when Nitrite starts climbing again I'll only dose with 1/4 of the original amount (0.5ppm) to keep the first set of bacteria alive whilst avoiding my mistake of dosing too much and making Nitrites build up to such extreme levels. Does this sound alright?

 

I dosed with another 2ppm Ammonia, and after further research I have decided that when Nitrite starts climbing again I'll only dose with 1/4 of the original amount (0.5ppm) to keep the first set of bacteria alive whilst avoiding my mistake of dosing too much and making Nitrites build up to such extreme levels. Does this sound alright?

I'd suggest not dosing any ammonia until nitrite hits zero. That way, you make sure nitrite does not reach extreme levels. Ammonia-oxidizing nitrifiers can go for a very long time ammonia-starved, so it is not necessary to keep feeding them each day.

 

Just tested (about 20 hours after last ammonia addition of 2ppm). Test results are all over the place.
pH is suddenly down to 6.0 from 6.6.
Ammonia (which has for the last 2 weeks returned to a renowned 0ppm 24 hours after each dosage) is now only 1ppm.
Nitrite: 0ppm
Nitrate: 30-40ppm

Obviously the pH has decreased somehow and the bacteria aren't working well. I am completely despairing. I thought doing a fishless cycle with ammonia, heaps and heaps of seeded material (I have lost count of how many bionoods, filter sponges, filter floss, gravel, java moss I have put in there from an established tank), live plants, and bottle bacteria would have cycled by now. I'm 3-4 weeks in and nothing is looking on track. Any advice is greatly appreciated... I don't know what to do anymore. Every time it seems to be getting underway, the next day things are a mess.

 

That pH drop is super weird. Honestly I have zero idea why that happened, so at this point I can't help further unfortunately. Unfortunate because it seemed like whatever type of nitrifier you had before could handle ammonia perfectly fine at 6.6 pH, but not at 6 pH it seems.

 

Could my water changes have been the culprit?
I did that one 100%, and then a 50% 2 days ago and another 50% yesterday...

 

Could my water changes have been the culprit?
I did that one 100%, and then a 50% 2 days ago and another 50% yesterday...

Hm. Could be. What's the pH of your tap water (or whatever your water source is)?

 

It's roughly neutral which is why I'm so confused. My other tank has recently also dropped to 6.0. Should I put that mesh bag of dolomite chips/crushed coral in? Will it cycle at a pH of 6.0? Is that too low for my fish in general? I don't know what to do...

 

Will it cycle at a pH of 6.0?

Yes. You asked that question before.

Is that too low for my fish in general?

Same list of species you gave above? Then it's not too low.

I have an important tipp for you: Do not follow all advice at once.
You have these options:
- Follow the advice from a store or manufacturer (which all want to sell stuff), add something to raise hardness (KH) and with it pH and keep buying for the whole lifetime of that tank. It will work, no question, but it will also keep you spending. Same goes for forum members that tell you the same. (medium-high hardness and accordingly pH, buffer comes from minerals)
- Follow the advice from forum members that can tell you from experience that this is not necessary to raise pH and you can get there with patience and no to little further expenses. (low hardness, accordingly low pH: buffer comes from humic substances)

But there is no way inbetween. Chemically or physically it's impossible and there is also no way around choosing one of these options as the tank has to be cycled at the end no matter what. You decide.

The tap having a higher pH than the tanks is likely due to an anti-corrosion plan by your provider. They add stuff (or remove CO2) to raise pH before sending it into the system to reduce the corrosion of the piping due to acidity. Try and leave a glass of tap standing for 24h test before and after.

Edit: You say nitrate is at 30-40mg/l. This has also influence on the pH as Nitrates are usually solved in water as nitric acid, lowering pH even further.

You will definitely need a GH/KH test kit, because without knowing these it's like poking in mirky water.

 

Ok, thanks MacZ. I will follow the advice from Forum members. So should I just wait for the current ammonia to decrease and take it from there? The pH test was slightly darker yellow that the chart's 6.0... does that mean it's lower? Will adding a bag of dolomite to my filter as a permanent addition not work to raise the pH to say 6.5 without tinkering with chemicals from the petshops? If so, would this product: https://www.bunnings.co.nz/yates-thrive-2-5kg-certified-organic-natural-dolomite-lime_p0329255 work? I have never used this kind of stuff for raising pH so not sure. I have no access to dolomite chips nor crushed coral. I have also read on another thread on this forum of others experiencing sudden pH drops. I do have quite a few plants that are not doing too well with several dying. There are quite a few leaves that die and fall off which I try to remove. Could this have caused a CO2 spike with contributed to the low pH? Thank you all who pitched in for your patience... I truly appreciate it.

 

So should I just wait for the current ammonia to decrease and take it from there?

Yes.

The pH test was slightly darker yellow that the chart's 6.0... does that mean it's lower?

I use completely different testing methods. What do you mean by darker? More towards orange?

Will adding a bag of dolomite to my filter as a permanent addition not work to raise the pH to say 6.5 without tinkering with chemicals from the petshops?

As I also explained above: It will work, but surpass 6.5. Unless using calculated chemicals (bicarbonate or baking soda) measured to the milligramm, all ways to raise KH (and with it pH) will saturate the water with carbonates, giving it a stable but high (over 8!) pH.

I have also read on another thread on this forum of others experiencing sudden pH drops.

I explain once more:
For a catastrophic pH-crash (= pH drops MORE than 1.5 points in less than 2 hours and UNDER a reading of 5) to even happen the following conditions have to apply: a. no buffer capacity (KH < 0°), b. a source of acidity must be releasing H+ ions. This can be strong acids (hydrochloric of sulfuric acids) added to lower pH OR, most often, accumulating Nitrates which are solved in water as Nitric acid. That would be the case in an overstocked tank with soft water and no waterchanges. So this is nothing to fear, because such condtions are not that usual to happen. Fish can experience pH changes of up to 4 points in nature over the course of a day every day in some habitats. Does it kill them? No.

So again, if you want to change anything about pH and hardness: Get GH and KH tested and best get your own kit. There's no way around that or hardening your water to the maximum.

I would now recommend to do the following:
Test your tap and your tank water for these values: pH, GH, KH, Nitrates. We have to untangle all these infos asked in single questions over the course of this thread to make a plan.

So do the tests on:
- Tapwater right out of the faucet
- tapwater left standing 24h
- tankwater from the running tank
- tankwater from the tank you're cycling

Only then we will get to the reasons. Everything else is just guesswork and that doesn't help.

I do have quite a few plants that are not doing too well with several dying. There are quite a few leaves that die and fall off which I try to remove. Could this have caused a CO2 spike with contributed to the low pH?

Rotting plant material can only cause an O2 (oxygen) depletion, which might have a similar effect, but the cause of the plants losing leaves is likely unrelated. Let's ignore that problem for the time being, one after the other and water chemistry is highest priority right now.

 

Ok, what I'll do is test my water once more today and then also take it to the petshop for them to test it to make sure mine's not defective. Then I will purchase that gH and kH kit. I will let you know the results as soon as I have them.
Update on water parameters (I didn't dose anymore because ammonia had not been returning to zero as it had been doing) a day and a half after last 2ppm dosage:
Ammonia: 1ppm
Nitrite: 0ppm
Nitrate: 30-40ppm
pH: 6.0
Is there any way around buying a gH and kH test kit? It's really out of my budget since I am functioning on allowances and birthday money here
Is adding a very small bioload worth of fish (6 neon tetras) a completely wild thought? Since Nitrites are at 0 and I will do a WC to lower Nitrates which will inevitably lower the existing ammonia, should it be safe for fish? At this pH the ammonia is ammonium and therefore not toxic to fish... giving the bacteria as long as it needs to colonise alongside? I know this will send me into a fish in cycle but just running through all my options and not wanting to go down a road so technical if possible... is there an easier way? Again, thank you for your patience with me - I know I have run out of it!
Just added a TON of gorgeous, healthy and thriving plants. Hopefully they will help with ammonia consumption in the future.

 

Today I went to my local pet store ( a family owned business, very helpful and does not just try to sell me stuff). I had them test my water just to make sure my kit wasn't defective. It wasn't. They suggested placing some oyster grit into the tank and even said that it could become a permanent addition to the tank to keep the pH at around 6.6-6.8 and buffer the kH a bit higher, since it was possible that the pH might be in the fives. My very large piece of driftwood and rainwater truly acidified the water.

So I got a small bag of bird grit and put 1/2 cup of rinsed oyster grit in a mesh bag in my filter. About 6 hours later I tested and pH had risen to 6.5. I appreciate all the info and I do understand that it would have been better to buy the gH and kH kit, but it is truly out of my budget. The pH is incredibly low, and it dropped from 6.6 to 6.0 at the least in only a couple of days, indicating that kH is also very low. I didn't see the need to test for absolute specific numbers since this wouldn't really change my course of action. I have some more questions though:

1) Is 1/2 cup for a 20 gallon tank at pH 6.0 (I still don't know the exact kH but I assume it's quite low because of the pH crash and large driftwood) a good amount to keep it at a steady pH in the late 6's with a steady, healthy kH too?
2) Will this amount oyster grit raise the kH higher than what is good for my fish (I know this is difficult to say without having tested it but any thoughts?)
3) Will this amount of oyster grit add too much calcium?
4) How often should I replace the grit to ensure I keep a steady and reliable pH and kH?

Thanks again for your responses, but unfortunately, for the time being, I have not been able to get that gH and kH kit - just trying my best to work around it.

Any more tips? Thanks.

 

It's the same thing. Nothing changed from what I said before.

1) Is 1/2 cup for a 20 gallon tank at pH 6.0 (I still don't know the exact kH but I assume it's quite low because of the pH crash and large driftwood) a good amount to keep it at a steady pH in the late 6's with a steady, healthy kH too?

You had no pH crash. Just a small drop. The crushed oyster shells will raise KH, GH and pH to the same levels as with limestone or crushed coral. As always with nature products one can only estimate the exact numbers. Adding it will push the pH into the 7-8 range, that's the best possible prognosis.

2) Will this amount oyster grit raise the kH higher than what is good for my fish (I know this is difficult to say without having tested it but any thoughts?)

Good for your (softwater) fish would be no KH or GH. Most people only push both up either for plants, invertebrates or out of an irrational fear of pH crashes.

3) Will this amount of oyster grit add too much calcium?

Can't tell. It will add calcium until the water is saturated and/or the shells depleted.

4) How often should I replace the grit to ensure I keep a steady and reliable pH and kH?

Again, nature products. You will have to test regularly to find out. The more often and the bigger percentages of waterchanges you do (should be about 50%/week) the faster the stuff is depleted.

So... yeah. LFS made money. Good for them.

Thanks again for your responses, but unfortunately, for the time being, I have not been able to get that gH and kH kit - just trying my best to work around it.

And with said money you could have ordered one. When tinkering with pH not knowing the KH is careless.

In my opinion you are afraid of things you don't have to fear (pH crash and not-cycling of the tank), threw out money for nothing and circle back to the same spot as before. I don't see how I may help still, I'm only repeating info by now.

So I bid you good luck with your tank.

 

Thank you for your thoughts and time. I was just concerned the pH might be well into the 5's. I will put even less than 1/2 cup grit to not saturate the water to such high kH and pH - all I can do now is a little bit of guesswork, unfortunately. I appreciate your patience with me and answering all my questions.

The LFS made $2.50 out of me. The test kit cost $35.

 

You're welcome. Good luck, still.

Should anything go haywire, read up on the stuff I posted, might be helpful.

The test kit cost $35.

Worth it 100%.