Maintain stable KH/pH

Hi!

I have a fairly new tank and test the water daily. I use the test strips, which I’ve heard mixed reviews about. Anyways, ever since using them my KH has consistently remained non-existent (yellow on strip). My pH was at a stable “neutral” (orange on strip, between 6.8-7). However, for the past few days while my KH is still at 0, my pH has dropped to the more acidic end around 6.

I have a Betta in a 5 gal and I’ve been moving decor around quite often (not ideal, I know) so I was wondering if that could make it fluctuate. I also have some frogbit and two moss balls. I’m going to resist any further “feng shui” so he doesn’t get too stressed. He has seemed perfectly fine and is eating well

I’ve also used a strip and placed it right under the faucet and my direct tap water pH was also “neutral.” This is making me think something in the tank is making it drop. I’m still in the process of cycling, so I don’t want the pH to affect that. Is it worth purchasing some crushed coral or an alkaline buffer, or should I continue to monitor and see if it evens out?

I never knew there was so much to water chemistry

 

I’m in the same boat, 0kh 7ph out of tap and tank sits around 6.5. I have driftwood and indian almond leaves, which can lower the ph and is likely the cause for me. What types of things are in your tank? Any decomposing organic thing will create acid and drop the ph. Adding crushed coral will raise kh, which is a buffer for ph, as acid eats the kh before it lowers ph. So I’m currently running a trial of 2 tbsp crushed coral in my filter. So far it’s been a month and I’ve seen no increase in kh or ph, so I plan on increasing the amount slowly until I see an effect. The great thing about crushed coral is that the change in chemistry is slow and steady, which is better than sudden changes with buffers like baking soda. Having a kh of 0 is always a risk for a sudden ph crash, so having kh is preferable to prevent any issues later on. The betta will get used to it’s acidic conditions, but might be stressed and therefore more susceptible to disease. Beneficial bacteria also starves at low ph levels due to acid changing ammonia to ammonium, which bb can’t eat.

This is probably a very confusing paragraph just to say that yes, I think you should add crushed coral to increase kh. The chemistry is super confusing.

 

I’m in the same boat, 0kh 7ph out of tap and tank sits around 6.5. I have driftwood and indian almond leaves, which can lower the ph and is likely the cause for me. What types of things are in your tank? Any decomposing organic thing will create acid and drop the ph. Adding crushed coral will raise kh, which is a buffer for ph, as acid eats the kh before it lowers ph. So I’m currently running a trial of 2 tbsp crushed coral in my filter. So far it’s been a month and I’ve seen no increase in kh or ph, so I plan on increasing the amount slowly until I see an effect. The great thing about crushed coral is that the change in chemistry is slow and steady, which is better than sudden changes with buffers like baking soda. Having a kh of 0 is always a risk for a sudden ph crash, so having kh is preferable to prevent any issues later on. The betta will get used to it’s acidic conditions, but might be stressed and therefore more susceptible to disease. Beneficial bacteria also starves at low ph levels due to acid changing ammonia to ammonium, which bb can’t eat.

This is probably a very confusing paragraph just to say that yes, I think you should add crushed coral to increase kh. The chemistry is super confusing.

Thanks for your response! It actually made perfect sense because I have been doing A LOT of research on all of these different water parameters. I was worried that a low pH would starve the bacteria and I’m glad that you mentioned crushed coral has a slow and steady effect; I considered using baking soda, but wasn’t sure on how to use it so there wasn’t a drastic increase.

Other than the plants I mentioned, there’s no decaying matter that would possibly have that much of an effect because I’ve been doing partial water changes (siphoning gravel too) quite frequently (maybe too frequently). I originally thought that any ammonia reading on the API test kit was grounds for a water change, but reading more into it, I actually need to let some of the ammonia remain to create the nitrites.

Needless to say I was not a fan of chemistry in school!

 

You don’t want ammonia + nitrites together to go above 1 ppm during a fish-in cycle, so test and keep it below that reading. That’s the typical recommendation here, bettas are very hardy fish so I think a little ammonia won’t hurt him long-term if it’s just during the month it takes to cycle. I wouldn’t let it get too high, but yes, the bacteria need SOMETHING to eat to actually cycle the tank. Removing ALL the ammonia just means you’ll never cycle. That’s why ammonia locking / ammonia eating products aren’t good. But, that’s about the cycle not the kh/ph haha. It is strange that your ph is dropping so dramatically when you are doing such frequent water changes. It could be that your tap water doesn’t have anything to buffer it and it naturally drops this low. Leave out a cup of tap water for 24 hours and test the ph. I’d be willing to bet the ph naturally drops and that nothing in the tank is the cause.

 

Yes I’ve been paranoid about them getting over the .5 ppm mark so I’ve been changing the water frequently. I do have some cycled media in the tank so I’m hoping that’s helping. I am going to do what you recommend and see if the pH drops within a 24 hour range. Also might bring a sample to my LFS and see if my test strips are just garbage.

 

API does sell a liquid kh/gh and ph test kit which I have and it exactly matched both API and Tetra’s test strips, so I’ve had pretty good accuracy with them. But yeah lots of people say they’re not as accurate. I wouldn’t trust a pet store either though or even most of the lfs I know... api liquid kits all the way

 

I use their liquid pH kit but I’m thinking I might as well invest in the master kit they sell to cover all of my bases

So I let a cup of my tap water sit overnight. I tested it before and it had the same pH (neutral) as it did this morning. The strip on the right is from my tank.

 

Hm, maybe someone else can chime in and explain it. I know tanks trend acidic over time but yours is a new tank and it doesn’t sound like anything in the tank would make it acidic. Regardless of the reasoning, crushed coral should help.

 

Hi!

I have a fairly new tank and test the water daily. I use the test strips, which I’ve heard mixed reviews about. Anyways, ever since using them my KH has consistently remained non-existent (yellow on strip). My pH was at a stable “neutral” (orange on strip, between 6.8-7). However, for the past few days while my KH is still at 0, my pH has dropped to the more acidic end around 6.

I have a Betta in a 5 gal and I’ve been moving decor around quite often (not ideal, I know) so I was wondering if that could make it fluctuate. I also have some frogbit and two moss balls. I’m going to resist any further “feng shui” so he doesn’t get too stressed. He has seemed perfectly fine and is eating well

I’ve also used a strip and placed it right under the faucet and my direct tap water pH was also “neutral.” This is making me think something in the tank is making it drop. I’m still in the process of cycling, so I don’t want the pH to affect that. Is it worth purchasing some crushed coral or an alkaline buffer, or should I continue to monitor and see if it evens out?

I never knew there was so much to water chemistry

0 KH is never good, because even small amount of organics could cause a PH drop, like you experienced. The higher the dKH, the less likely the PH is to change. My tap water come out at around 2, and that drops down to zero within 3 days due to the woods and leaves I have. What I do is add Seachem Alkaline buffer every water change until its at about 6 dKH, which is low enough for plants to be happy, but still high enough to prevent PH swings. My PH out of the tap is also neutral, about 7, and the alkaline buffer raises it to 7.6. Betta should be perfectly fine with those parameters, but just make sure you slowly raise the levels as you do water changes, all at once could cause stress. Hope this helps

 

UPDATE: I purchased the API Master Test Kit, the first picture is my pH in the tank and the second picture is my pH right out of the faucet. Does anyone have an idea of what could be causing this drastic change? I use generic pet store gravel as substrate, a few plastic and silk plants, a small house-like ornament from Petsmart and I have a TopFin heater. I was using Aqueon Betta pellets but just switched to Omega One Betta Buffet and I dose with Prime for water changes.

I have crushed coral on the way!

 

You must increase the KH of your tank immediately. You are having a classic KH/pH crash. That means your KH is 0 and your pH drops rapidly.

You need to add some buffers to the water ASAP. Use some baking soda in water used to change the aquarium. Get the KH to read about 5 degrees in the change water. The fish will be fine with this transition as long as it is dissolved first. Use this water to start changing the tank water, and after a few changes get your tank up to a KH of 5 or so.


Here is the problem. The beneficial bacteria use the carbonate (KH) to convert ammonia. Without KH, the cycle will stop and everything may die. This is why we test for KH. To make sure it is NOT zero!

Let me explain the low pH this way. Without buffers (KH) the pH is measuring the percent of Hydrogen in the water as a ratio of the amount of acid to the amount of alkalinity.

But with 0 alkalinity (0 KH) any small amount of acid will cause the ratio to jump down.

Once your water is buffered (that means you read about 5 KH), those same acids will not affect the pH as much.

But the pH is just the canary in the coal mine telling you something is wrong. What is wrong is that you have 0 KH and need to get that up or your tank will die because the KH is needed to process ammonia waste.

 

You could honestly just snap a cuttlefish bone in half and drop it in your tank

 

You must increase the KH of your tank immediately. You are having a classic KH/pH crash. That means your KH is 0 and your pH drops rapidly.

You need to add some buffers to the water ASAP. Use some baking soda in water used to change the aquarium. Get the KH to read about 5 degrees in the change water. The fish will be fine with this transition as long as it is dissolved first. Use this water to start changing the tank water, and after a few changes get your tank up to a KH of 5 or so.


Here is the problem. The beneficial bacteria use the carbonate (KH) to convert ammonia. Without KH, the cycle will stop and everything may die. This is why we test for KH. To make sure it is NOT zero!

Let me explain the low pH this way. Without buffers (KH) the pH is measuring the percent of Hydrogen in the water as a ratio of the amount of acid to the amount of alkalinity.

But with 0 alkalinity (0 KH) any small amount of acid will cause the ratio to jump down.

Once your water is buffered (that means you read about 5 KH), those same acids will not affect the pH as much.

But the pH is just the canary in the coal mine telling you something is wrong. What is wrong is that you have 0 KH and need to get that up or your tank will die because the KH is needed to process ammonia waste.

Thank you! My tank is not cycled yet anyway and I wonder if this is why. I’ll add some baking soda while waiting for the coral to arrive!

 

If you don't have a KH test kit, remember this formula:
One teaspoon of baking soda per 50 Liters raises the KH by about 4 dH

Thank you! My tank is not cycled yet anyway and I wonder if this is why. I’ll add some baking soda while waiting for the coral to arrive!

Yes, lack of KH stops the cycle and ammonia will rise.

 

You could honestly just snap a cuttlefish bone in half and drop it in your tank

Cuttlefish bones increase gh, not kh. Gh doesn't affect kh.

Use a half cup of crushed coral in a bag in the hob. Test in 24 hours. If no increase, add another tablespoon until you see it slightly increase in a 24 hour time frame. It'll continue to slowly increase kh until it levels out. ph will increase as kh increases.

Don't personally like the baking soda option as it causes fast changes in params and needs to be consistently added and tested. Crushed coral is just a drop n forget method.

You don't need to hurriedly increase your kh and ph. That will cause more damage to the fish than a slow, steady increase. You can just wait for the crushed coral to come in. As I said before, watch for an ammonia spike and treat the tank as though you are doing a fish-in cycle because the bacteria are likely starved right now from the low ph.

 

You could honestly just snap a cuttlefish bone in half and drop it in your tank

Some folks have baking soda in the pantry. Others have cuttle fish bones lying around

 

Cuttlefish bones increase gh, not kh. Gh doesn't affect kh.

Use a half cup of crushed coral in a bag in the hob. Test in 24 hours. If no increase, add another tablespoon until you see it slightly increase in a 24 hour time frame. It'll continue to slowly increase kh until it levels out. ph will increase as kh increases.

Don't personally like the baking soda option as it causes fast changes in params and needs to be consistently added and tested. Crushed coral is just a drop n forget method.

You don't need to hurriedly increase your kh and ph. That will cause more damage to the fish than a slow, steady increase. You can just wait for the crushed coral to come in. As I said before, watch for an ammonia spike and treat the tank as though you are doing a fish-in cycle because the bacteria are likely starved right now from the low ph.

Thank you!!!

 

Cuttlefish bones increase gh, not kh. Gh doesn't affect kh.

Use a half cup of crushed coral in a bag in the hob. Test in 24 hours. If no increase, add another tablespoon until you see it slightly increase in a 24 hour time frame. It'll continue to slowly increase kh until it levels out. ph will increase as kh increases.

Don't personally like the baking soda option as it causes fast changes in params and needs to be consistently added and tested. Crushed coral is just a drop n forget method.

You don't need to hurriedly increase your kh and ph. That will cause more damage to the fish than a slow, steady increase. You can just wait for the crushed coral to come in. As I said before, watch for an ammonia spike and treat the tank as though you are doing a fish-in cycle because the bacteria are likely starved right now from the low ph.

Actually it increases both according to Google and old threads here on Fishlore. Never tried it myself though so I could be wrong!

 

Cuttlefish bones increase gh, not kh. Gh doesn't affect kh.

Use a half cup of crushed coral in a bag in the hob. Test in 24 hours. If no increase, add another tablespoon until you see it slightly increase in a 24 hour time frame. It'll continue to slowly increase kh until it levels out. ph will increase as kh increases.

Don't personally like the baking soda option as it causes fast changes in params and needs to be consistently added and tested. Crushed coral is just a drop n forget method.

You don't need to hurriedly increase your kh and ph. That will cause more damage to the fish than a slow, steady increase. You can just wait for the crushed coral to come in. As I said before, watch for an ammonia spike and treat the tank as though you are doing a fish-in cycle because the bacteria are likely starved right now from the low ph.

Crushed coral is very slow.

Increasing pH rapidly has no effect on fish. Ponds naturally fluctuate rapidly in pH but they stay within a range. Having pH drop outside of their healthy range does hurt them. It is not the speed of the change but the pH value that you get to that hurts. pH below 6.0 makes nitrite toxic and harms fish. The OP has a tank with pH of 6.0 and is about to crash.

Adding some baking soda now will keep your tank from crashing, raise the pH to safe levels, restart the nitrogen cycle and save the tank.

You can then add crushed coral too to keep it stable for the long term.

 

Don't personally like the baking soda option as it causes fast changes in params and needs to be consistently added and tested. Crushed coral is just a drop n forget method.

Just wanting to +1 this. It doesn't apply to me, my ph is a rock solid (pun intended) 8.1... but I think CC will also only raise PH to about 7.2, then stops. So you wouldn't even need to worry about overdoing it.

 

Just wanting to +1 this. It doesn't apply to me, my ph is a rock solid (pun intended) 8.1... but I think CC will also only raise PH to about 7.2, then stops. So you wouldn't even need to worry about overdoing it.

In general that is true. But not for a tank that has already crashed.

 

Increasing pH rapidly has no effect on fish

Agree to disagree on this one. All my research and reading into this forum and from what people here that I trust have said, it’s worse to have params fluctuate rapidly than for them to fall outside of the “norms” for the type of fish. But, everyone has their own opinion - it’s up to OP to decide if they want to use baking soda to increase it now immediately, or hold out and use crushed coral. Both are valid options and totally dependent on what OP thinks is best for his or her fish friends.

I want to add, my tank has a ph of 6.5 and kh of 0 and has had fish in these params for a year or so without ill effects. I’m running crushed coral now to add the kh buffer because all my research shows that a kh of 0 is dangerous due to RAPID ph drops/crashes. My tank didn’t rapidly crash because of the 0kh - it has slowly gone down over the year of set up (which is why I decided to look into it).

 

Agree to disagree on this one. All my research and reading into this forum and from what people here that I trust have said, it’s worse to have params fluctuate rapidly than for them to fall outside of the “norms” for the type of fish. But, everyone has their own opinion - it’s up to OP to decide if they want to use baking soda to increase it now immediately, or hold out and use crushed coral. Both are valid options and totally dependent on what OP thinks is best for his or her fish friends.

Have you ever looked at how much the pH of the natural environment fluctuates, and rapidly so? This will put you at ease regarding pH changes.

We are not talking about a norm for a fish. 6.0 pH is low for all fish.

 

Have you ever looked at how much the pH of the natural environment fluctuates, and rapidly so? This will put you at ease regarding pH changes.

We are not talking about a norm for a fish. 6.0 pH is low for all fish.

The fish we own now are typically not wild caught and are not used to natural environment fluctuations. Of course if OP has a wild caught fish you may be right, I have no idea what it’s like for fish in the wild.

 

The fish we own now are typically not wild caught and are not used to natural environment fluctuations. Of course if OP has a wild caught fish you may be right, I have no idea what it’s like for fish in the wild.

Ability to deal with pH fluctuations goes deep. It is chemistry.
I was amazed when I first started learning Limnology. One of the things is how much pH fluctuations happen naturally and our fish are perfectly suited for regardless of their breeding. Meanwhile a tank with 6.0 pH is crashing.

Agree to disagree on this one. All my research and reading into this forum and from what people here that I trust have said, it’s worse to have params fluctuate rapidly than for them to fall outside of the “norms” for the type of fish. But, everyone has their own opinion - it’s up to OP to decide if they want to use baking soda to increase it now immediately, or hold out and use crushed coral. Both are valid options and totally dependent on what OP thinks is best for his or her fish friends.

I want to add, my tank has a ph of 6.5 and kh of 0 and has had fish in these params for a year or so without ill effects. I’m running crushed coral now to add the kh buffer because all my research shows that a kh of 0 is dangerous due to RAPID ph drops/crashes. My tank didn’t rapidly crash because of the 0kh - it has slowly gone down over the year of set up (which is why I decided to look into it).

You have reached an equilibrium @ 6.5 pH and 0-1 KH, but with crushed coral which keeps slowly adding carbonates.

Please understand that when you use API test kit and add one drop and see the color change, that only confirms that KH is in between 0 an 17 ppm. It could be 0 or it could be up to 17 ppm.

When KH hits zero the nitrogen cycle stops.

If the rate at which your BB convert ammonia (and uses KH) is equal to the rate that the crushed coral dissolves, you stay steady. Remove the crushed coral and the tank crashes. This is a very slow process.

The OP has pH of 6.0 right now unfortunately. That is a different situation than your tank. Adding a little buffer is needed in case the KH is actually zero - which it may be. Why risk it? If crushed coral was already part of the tank I would not be concerned. The equilibrium process would have already happened.

 

I appreciate both sides of information, constantly learning new things here.

 

I appreciate both sides of information, constantly learning new things here.

I think you have enough information for both sides to make your decision.

My tank just recently got CC like a week ago and it’s done nothing yet so I just added more today. My tank stayed at 0kh 6.5 ph without it. But I want the buffer just in case for crashes.

Keep us informed with how it all works put!

 

Baking soda isn't unstable per se. Calcium carbonate dissolves slowly so you have to use a lot of it which also lasts longer. If you put the same amount (adjusted for moles of carbonate) of each in a tank it would be equally stable.

You can add baking soda in small quantities and it won't change pH too quickly. You can add it regularly and it will keep pH steady.

If you were to use a doser to dose baking soda you could achieve the same thing as using a whole bunch calcium carbonate (and also maintain a higher pH, if desired).

The only difference is that baking soda dissolves right away and calcium carbonate doesn't.

That being said, I would use baking soda (or the potassium equivalent in a planted tank) to carefully raise pH in a tank with crashed pH. After things settle down then decide whether you want to use baking soda or CaCO3.


There's a lot more scientific evidence that being outside a certain pH range is harmful to fish than there is that fluctuations are harmful. It may very well be that both are harmful but I haven't found enough evidence (only 1-2 studies) to convince me to a high degree of certainty that pH fluctuations are bad.

What we do know is that there's a pH range of roughly 6.5-9 where most fish would be fine. Some do better at somewhat different pH ranges. Some also have special adaptations that allow them to survive outside that range but would do better at less extreme pHs. You couldn't take a fish that hasn't evolved to survive in low pH water and acclimate it to a pH of <5.

Nitrifying bacteria do best around 7.8 which is a value that's fine for most fish so that's the pH I aim for.

 

I think you have enough information for both sides to make your decision.

My tank just recently got CC like a week ago and it’s done nothing yet so I just added more today. My tank stayed at 0kh 6.5 ph without it. But I want the buffer just in case for crashes.

Keep us informed with how it all works put!

How are you measuring the 0 KH? If you are using the API test, then when you add 1 drop it changes color which confirms only that you have anywhere between 0 and 17 ppm KH.

The problem is when you hit 0 the nitrogen cycle stops.

 

New question! Should I wait to stabilize my KH before adding Indian almond leaves? I wanted to add one to my 5g but I don’t know if I should wait for the crushed coral to work first.

 

New question! Should I wait to stabilize my KH before adding Indian almond leaves? I wanted to add one to my 5g but I don’t know if I should wait for the crushed coral to work first.

Wait for kh to rise. As the IALs decompose, it releases acid and will drop the ph further.

 

That’s what I figured, thanks

 

to carefully raise pH

This is exactly why I'm hesitant to advise folks doing this. Generally speaking, people asking this question aren't going to be the most experienced aquarium keepers. What precisely does "carefully" mean? The likelihood of compounding problems by taking shortcuts is too high imho. Slow, steady, and stable wins the race with aquariums.

 

Update! I put in a cup of crushed coral into a media bag in my filter yesterday. Today my ph has raised slightly, my KH has not really risen at all but my GH is super high, like 120. I’ve been measuring KH/GH with strips so maybe I’ll invest in the liquid if needed. I might take some of the coral out since it’s only a 5g.

 

Update! I put in a cup of crushed coral into a media bag in my filter yesterday. Today my ph has raised slightly, my KH has not really risen at all but my GH is super high, like 120. I’ve been measuring KH/GH with strips so maybe I’ll invest in the liquid if needed. I might take some of the coral out since it’s only a 5g.

GH is not super high, just regular. No problem.

There is no reason to remove crushed coral if you are concerned about the water. Curshed coral dissolves as needed. If the pH is low it dissolves faster. Above 7.0 it stops dissolving. It regulates itself.

 

GH is not super high, just regular. No problem.

There is no reason to remove crushed coral if you are concerned about the water. Curshed coral dissolves as needed. If the pH is low it dissolves faster. Above 7.0 it stops dissolving. It regulates itself.

Thank you! One last question, when I jiggled the media bag a bunch of dust filled the water. I had rinsed it before hand and I know eventually it’ll get filtered out but is it okay for my fish?

Another update: The coral dust cleared out quickly, I just got nervous initially that it would take a while.
The first picture is my pH in my tank today, I’d say it’s about 6.9? The second picture is the pH out of my tap. I guess my only question now is since they’re essentially the same, I can use my tap water without modifying it at all, correct? I still have yet to see any change on the API test strip regarding KH, but I’m assuming it just takes some time.

 

Another update: The coral dust cleared out quickly, I just got nervous initially that it would take a while.
The first picture is my pH in my tank today, I’d say it’s about 6.9? The second picture is the pH out of my tap. I guess my only question now is since they’re essentially the same, I can use my tap water without modifying it at all, correct? I still have yet to see any change on the API test strip regarding KH, but I’m assuming it just takes some time.

My coral is also working now yeah since they’re the same you can change it no worries. The kh is a bit different of course but just keep the water changes 50% or less and it’s fine

 

My coral is also working now yeah since they’re the same you can change it no worries. The kh is a bit different of course but just keep the water changes 50% or less and it’s fine

Glad yours is working too! Thanks for all of your support

 

I just returned from a 3 day vacation and my KH is now at 40! My pH is around 7.4 and I have a question regarding my cycle. When I initially tested ammonia, it was at 0 and I was shocked. After about 5 minutes it turned into this really pale yellow color which I thought was odd. I retested and this time there was a slight tinge of green, but it looked less than .25. I know my nitrates are at 0 still, but I’m wondering if my plants are taking care of them since it’s such a small tank? There were no water changes performed before I left for vacation.

 

Aquariums are about achieving balance, and you are doing just that!

Since you are using the API test strips to measure KH, the 40 number you are reading is in ppm (parts per million). That is a a great number for you to have.

In some of the posts above we talked about KH in terms of degrees, like 0 or 1 degrees.

1 degree of KH is the same as 18 ppm.

So you have 40 ppm of KH, which is about 2 degrees KH.

That's great, your plants and fish will be happy.

Your aquarium's biological filter does not like KH of 0. Plants don't like KH to be too high (less than 5 degrees is good for plants AND fish).