Undergravel Filter Riser Tube with Buffer Added

My small tank with an undergravel filter and black gravel is having pH crashes. I check it every day and have noticed it dropped from 7.4 on 4 days ago to 6.4 yesterday. I gave it small doses of pH up over many hours yesterday and now it's 7 and holding overnight. My tap water comes in about 7.9 pH so I did a 10% water change and will do the same today.

I dropped a small amount of crushed oyster shells down the riser tube...with black substrate, I don't want to add white oyster shells. I use a pH meter, so checking it regularly is easy. I'm planning to add more crushed oyster shells down the riser as I monitor the pH fluctuations. If it starts dropping more, I can drop a few more pieces. As it dissolves, I can continue to add a couple pieces to compensate.

I ordered Equilibrium. I have the master test kit and the KH GH test kit. I test the water every day and keep a log to notice trends. KH is 2, GH is 5. I have a snail and a betta with three plants. Betta seems very happy. The snail is on the move a lot, but seems to be falling off the glass regularly of late.

Ammonia and Nitrites 0, Nitrates 20

Any suggestions are welcome and appreciated.

 

What size is your small tank? What is your water change intervals and amount? In my experience regular w/c will keep the tank water PH near the tap. (10% is not much) I'd not add PH up because it's usually only temporary. I also don't think a few shells will do much to the PH, and certainly would not want the them blocking flow in my uplift tube.

 

Not many people use undergravel filters these days, but I have been using them for several decades. The problem with dumping crushed coral down the riser tube is that you will affect the flow through the filter. In order to be effective, there has to be a good flow of oxygenated water through the gravel bed. If you do not get enough water flow and the bacteria do not get sufficient oxygen, anaerobic bacteria can develop in the gravel bed causing sulfates to be converted to hydrogen sulfide, which is toxic and smells terrible.

It would be better to remove a thin layer of your black gravel, add a thin layer of the white shells and then cover them back up with the black gravel. You could also purchase a small HOB filter and place a small bag of crushed coral in that filter.

You said the pH of your tap water is 7.9. Thus, doing regular water changes is the best way to raise pH.

Having a pH meter is great as they give you quick readings. Keeping the meter properly calibrated, however, is not so convenient. Thus, even if you have a pH meter, you should still use pH indicators occasionally to make sure the meter has not drifted. If you are targeting a pH of 7.0, the bromothymol blue indicator solution should be green at that pH. it is blue at higher pH levels and yellow at lower levels.

 

Not many people use undergravel filters these days, but I have been using them for several decades. The problem with dumping crushed coral down the riser tube is that you will affect the flow through the filter. In order to be effective, there has to be a good flow of oxygenated water through the gravel bed. If you do not get enough water flow and the bacteria do not get sufficient oxygen, anaerobic bacteria can develop in the gravel bed causing sulfates to be converted to hydrogen sulfide, which is toxic and smells terrible.

It would be better to remove a thin layer of your black gravel, add a thin layer of the white shells and then cover them back up with the black gravel. You could also purchase a small HOB filter and place a small bag of crushed coral in that filter.

You said the pH of your tap water is 7.9. Thus, doing regular water changes is the best way to raise pH.

Having a pH meter is great as they give you quick readings. Keeping the meter properly calibrated, however, is not so convenient. Thus, even if you have a pH meter, you should still use pH indicators occasionally to make sure the meter has not drifted. If you are targeting a pH of 7.0, the bromothymol blue indicator solution should be green at that pH. it is blue at higher pH levels and yellow at lower levels.

I agree about the concern of blocking water flow. I added just a few pieces. I like the idea of digging up some of the substrate, dropping in the crushed oyster shells, and covering. I'm not going to do deep gravel vacs very often, so this might work.

I change 5% of the water per day. I did 10% yesterday and will do the same today. It's easy on a 2.5 gallon tank, just take a large glass of water out and then top up.

What size is your small tank? What is your water change intervals and amount? In my experience regular w/c will keep the tank water PH near the tap. (10% is not much) I'd not add PH up because it's usually only temporary. I also don't think a few shells will do much to the PH, and certainly would not want the them blocking flow in my uplift tube.

5% daily water changes have been my routine the last few weeks...so 35% per week. I can up it to 10% easily, 70% per week. It's only 2.5 gallons so a large glassful represents 5% of the volume. I'm very cautious with pH up...I know it's just a bandaid. I'm trying to find a good longer term way to keep it stable. I have to go away for a week next month and need to feel comfortable it won't get out of hand while I'm away.

I'm planning to have the neighbors drop a few pellets of food into my betta each day while I'm away, but asking them to test, adjust, and do water changes seems like too much. I'll just get it to as best condition as I can before leaving.

 

A 5 or 10 gallon tank 'll fix everything.

I'll bet your 2.5 is cute though. Gotta pic?

Over 25 years ago I actually had my first and only Betta in a 2.5 tank... yes, with UGF. He used to flare at the ramshorn snails.

 

Shells or bone or all the other buffer styles of adding a few bits doesn't work well to actually buffer the pH, you need at least 1 pound per 10 gallons, a quarter pound in 2.5 gallons, of calcium carbonate as an example.
Shell or cuttlebone is fine, but it's the surface area and volume of it and exposed areas that do the buffering so while shell edges will do something, it's not as effective as the entire surface being ready to buffer at once like crushed coral, and having enough of it. If you insist on having the black substrate, see about hiding a quarter pound under the undergravel filter or below the gravel. there's lots of methods of getting calcium carbonate for a buffer, some are more accessible than others. the oyster shells, if ground up, would be fine and just as effective as the crushed coral/aragonite,, but you'd need more of it. I'd start with an 1/8 of a pound and see what it's doing to buffer and add another 1/8th if it's not holding, because I'm guessing you don't want more than you really need. but a few bits isn't going to do much at all as far as stability long term.

keep in mind all of these sources of calcium carbonate aren't pure 100% calcium carbonate, they can be depleted long before they completely dissolve and disappear. don't wait for the need to be replaced because it's disappeared, your pH will be screwed by then. Oyster Shells are 90% CC, Cuttlebone is 85% CC, Crushed coral varies from 90-95% CC. Limestone can range from 80%-99% CC. but dropping a half pound Limestone rock in there won't do what you want it to because of the surface area available and most of it being locked up inside the stone vs. crushed methods.

little bits will deplete quickly or not keep up, more of it will give you duration and stability.

 

A 5 or 10 gallon tank 'll fix everything.

I'll bet your 2.5 is cute though. Gotta pic?

Over 25 years ago I actually had my first and only Betta in a 2.5 tank... yes, with UGF. He used to flare at the ramshorn snails.

Sonic The Betta - Mystery Snail | Photos Forum | 521262

I will probably get a larger tank in the future. I keep a craigslist and facebook search going trying to find the right fit. I want a rimless cube I think...maybe I'll get some free time and explore making my own.

I can't fill the tank all the way up. The black around the rim causes a reflection...he sees himself and spends all his time flaring and attacking his own reflection. Gills wide and fins spread. I know it's not good for him long-term to be in attack mode.

Shells or bone or all the other buffer styles of adding a few bits doesn't work well to actually buffer the pH, you need at least 1 pound per 10 gallons, a quarter pound in 2.5 gallons, of calcium carbonate as an example.
Shell or cuttlebone is fine, but it's the surface area and volume of it and exposed areas that do the buffering so while shell edges will do something, it's not as effective as the entire surface being ready to buffer at once like crushed coral, and having enough of it. If you insist on having the black substrate, see about hiding a quarter pound under the undergravel filter or below the gravel. there's lots of methods of getting calcium carbonate for a buffer, some are more accessible than others. the oyster shells, if ground up, would be fine and just as effective as the crushed coral/aragonite,, but you'd need more of it. I'd start with an 1/8 of a pound and see what it's doing to buffer and add another 1/8th if it's not holding, because I'm guessing you don't want more than you really need. but a few bits isn't going to do much at all as far as stability long term.

keep in mind all of these sources of calcium carbonate aren't pure 100% calcium carbonate, they can be depleted long before they completely dissolve and disappear. don't wait for the need to be replaced because it's disappeared, your pH will be screwed by then. Oyster Shells are 90% CC, Cuttlebone is 85% CC, Crushed coral varies from 90-95% CC. Limestone can range from 80%-99% CC. but dropping a half pound Limestone rock in there won't do what you want it to because of the surface area available and most of it being locked up inside the stone vs. crushed methods.

little bits will deplete quickly or not keep up, more of it will give you duration and stability.

I orders some Sun Grow balls to drop into the tank. I'm not sure if I'm allowed to post a link to amazon, but this is iit: https://www.amazon.com/dp/B07Q7TWFMJ?psc=1&smid=A131SO7MHPCPON&ref_=chk_typ_imgToDppsc=1&smid=A131SO7MHPCPON&ref_=chk_typ_imgToDp Not a lot of surface area. I'm thinking about putting a couple drops of pH up into my half gallon water change vessel. I condition and aerate the water before adding it to the tank...a drop or two each time might do the trick.

10% water change today again. Everything appears to have returned to stable. I'm back at 7.3-7.4. I'm just trying to avoid swings in pH. I want to keep it between 7-7.5 for the snail's sake.

 

Not many people use undergravel filters these days, but I have been using them for several decades. The problem with dumping crushed coral down the riser tube is that you will affect the flow through the filter. In order to be effective, there has to be a good flow of oxygenated water through the gravel bed. If you do not get enough water flow and the bacteria do not get sufficient oxygen, anaerobic bacteria can develop in the gravel bed causing sulfates to be converted to hydrogen sulfide, which is toxic and smells terrible.

It would be better to remove a thin layer of your black gravel, add a thin layer of the white shells and then cover them back up with the black gravel. You could also purchase a small HOB filter and place a small bag of crushed coral in that filter.

You said the pH of your tap water is 7.9. Thus, doing regular water changes is the best way to raise pH.

Having a pH meter is great as they give you quick readings. Keeping the meter properly calibrated, however, is not so convenient. Thus, even if you have a pH meter, you should still use pH indicators occasionally to make sure the meter has not drifted. If you are targeting a pH of 7.0, the bromothymol blue indicator solution should be green at that pH. it is blue at higher pH levels and yellow at lower levels.

I took your advice and removed some of my black gravel, put in 1/4 pound of crushed oyster shells, and then covered it in black gravel. I'm looking forward to not worry about the pH so much and hoping my Betta and Snail live to old age. Thank you

 

Hopefully, this will help stabilize the pH. However, there is nothing that keeps a tank stable more than volume. That is why the ocean is so stable. We cannot achieve that stability in an aquarium, but the bigger the better. Five gallons is really the smallest tank suitable for a Betta and 10 gallons is even better.

About once a quarter, Petco puts their 10 gallon tanks on sale. You used to be able to get them for a dollar a gallon, but with inflation, they might be slightly higher now. Admittedly, the cost of the tank is only a small portion of the total cost of an aquarium, but at least the sale will get you started in the right direction.

 

Hopefully, this will help stabilize the pH. However, there is nothing that keeps a tank stable more than volume. That is why the ocean is so stable. We cannot achieve that stability in an aquarium, but the bigger the better. Five gallons is really the smallest tank suitable for a Betta and 10 gallons is even better.

About once a quarter, Petco puts their 10 gallon tanks on sale. You used to be able to get them for a dollar a gallon, but with inflation, they might be slightly higher now. Admittedly, the cost of the tank is only a small portion of the total cost of an aquarium, but at least the sale will get you started in the right direction.

I understand bigger is better for stability. But I need to find a place to put a larger tank. Most of the areas of my living space get direct sunlight. The bedrooms would work, but I don't spend much time in there. Double that I'm a bargain hunter and want to buy a used rimless cube and it's not as simple as just going to petco for a new tank.

 

I'm pleased to report I didn't have a pH crash overnight like the last 4 nights. It was getting to the point I was thinking about taking the betta and snail back to the store coz I was concerned I would lose them. But I went to bed with 7.3 pH and woke to 7.4. I now feel confident.

My KH is 3 and GH is 6. I did a water change and everyone is happy.
This is a link to my log:
Fish Tank Chemistry

 

Looks promising. I'd hold off on the pH up, let the shells settle in some more and become dissolved solids , your log shows you are at or higher than you've been for KH and GH, with the pH in a while, which looks good, but I wouldn't mess with it beyond where it is, and let the shells do the work and see where it lands. 4 dKH or higher sill be good.but it won't be stable if using the pH up, which is using sodium carbonates to raise the pH. hopefully you see the KH continue to rise some every 24 hours but now that you aren't in the 2 range, it shouldn't be so rough on ya, if it balances off a little low, or 4ish, just add some more oyster shell and the KH will come up some more, so might the pH with the KH,
with the pH up product, on top of that shell rise, you might wind up with a high pH problem instead. so best to really just monitor, water change and let it all settle in and see where it levels off at. 4-8dKh or 4-8dGH is fine. a bit higher on the KH than 4 will give you more pH stability and some room for eventual depletion over time.
if it can settle at 6 dKH it would be fantastic and you can just replenish when you see the KH dropping to 5 or 4, without hitting the 3 or the 2 dKH again.

I'm really rooting for ya man! hahahaha LETTTTS GO!!!!!!

 

Looks promising. I'd hold off on the pH up, let the shells settle in some more and become dissolved solids , your log shows you are at or higher than you've been for KH and GH, with the pH in a while, which looks good, but I wouldn't mess with it beyond where it is, and let the shells do the work and see where it lands. 4 dKH or higher sill be good.but it won't be stable if using the pH up, which is using sodium carbonates to raise the pH. hopefully you see the KH continue to rise some every 24 hours but now that you aren't in the 2 range, it shouldn't be so rough on ya, if it balances off a little low, or 4ish, just add some more oyster shell and the KH will come up some more, so might the pH with the KH,
with the pH up product, on top of that shell rise, you might wind up with a high pH problem instead. so best to really just monitor, water change and let it all settle in and see where it levels off at. 4-8dKh or 4-8dGH is fine. a bit higher on the KH than 4 will give you more pH stability and some room for eventual depletion over time.
if it can settle at 6 dKH it would be fantastic and you can just replenish when you see the KH dropping to 5 or 4, without hitting the 3 or the 2 dKH again.

I'm really rooting for ya man! hahahaha LETTTTS GO!!!!!!

I've learned a lot. Thank you for the advice. I'll keep you posted on the status...pH is up to 7.7 now, but I expect to see it drop off some by morning. Definitely no more pH up at this point.

The tank parameters are now almost identical to my tap water (ph, GH, KH)...I think that means good things for keep thing thing stable. Water changes shouldn't affect the fish much.

 

This seems to be working out beautifully. KH 4, GH 8, pH 7.4.

If things start to get out of hand, I have an RO system I can use for water changes...might that with my tap water to get the GH in an ideal range. At least I think that makes sense.

Thanks again. I feel so much better about my chance for success without this pH moving around so much.

Fish Tank Chemistry

 

Parameters of 4 dKH, 8 dGH, and 7.4 pH are suitable for many fish.

Your tap water appears to be in a range suitable for water changes. If you have to top off the water level due to evaporation, then using RO water is great as you do not add minerals. However, for water changes, RO water is unsuitable unless to add minerals to the water.

My tap water is horrible, so I use RO water, but I add Seachem Equilibrium to bring the dGH to 7 and I add buffering compounds to raise the dKH and pH. I target 7.5 pH in my tanks as they contain community species. I always used tap water until I moved to my current home where the water was so bad.

 

This seems to be working out beautifully. KH 4, GH 8, pH 7.4.

If things start to get out of hand, I have an RO system I can use for water changes...might that with my tap water to get the GH in an ideal range. At least I think that makes sense.

Thanks again. I feel so much better about my chance for success without this pH moving around so much.

Fish Tank Chemistry

I don't mess with or use RO water, from what I know of it, it's when things are so bad with you base water or you need very specific parameters, then you'd want to start with stripped out water and add in just what you want or need and bring it up to the appropriate levels. I really don't recommend doing this, it's advanced and water chemistry, but if your a mad scientist that really wants to get into the nitty gritty of aquarium water, and have full control over it, that's what you'd probably want to do and use stripped out RO water to start and build it how you want it to be. Reverse osmosis produces high purity water free of water hardness, chemicals like chlorine, toxins, and removes up to 99% of dissolved solids in the water. darn near all zeros and blank, and removes flouride, calcium, magnesium, Iron, salt, like near everything gone.

SO, if you used RO, for a water change, just know it's got a near Zero KH anf GH. and a pH of 6 -6.5 or so. but under 7.

My opinion it's just reinventing the wheel when it's not necessary and in your case, all you really needed was to get a handle on the KH. I mean if you wanted to keep like cardinal tetras (pH 4.6- 6.2 ) or like Alcolapia alcalica (it's a cichlid from Lake Natron in Tanzania with a pH that goes from pH 9-12, pH 10.5 being the average) and there are other species with specific needs. Probably it makes sens to start from scratch on the water and put in what you need to get it where you want it in a controlled manner.
Also make sense when your water is so screwed up it's just easier to start from scratch and build it up than it is to try to break it down. Like if it bounces around depending on when you draw it, it would always be a different amount of adjustments needed, but starting with RO, it's always the same adjustment so when you have that dialed in, its the same process to build tank water after that every time and no variables.

​

 

I don't mess with or use RO water, from what I know of it, it's when things are so bad with you base water or you need very specific parameters, then you'd want to start with stripped out water and add in just what you want or need and bring it up to the appropriate levels. I really don't recommend doing this, it's advanced and water chemistry, but if your a mad scientist that really wants to get into the nitty gritty of aquarium water, and have full control over it, that's what you'd probably want to do and use stripped out RO water to start and build it how you want it to be. Reverse osmosis produces high purity water free of water hardness, chemicals like chlorine, toxins, and removes up to 99% of dissolved solids in the water. darn near all zeros and blank, and removes flouride, calcium, magnesium, Iron, salt, like near everything gone.

SO, if you used RO, for a water change, just know it's got a near Zero KH anf GH. and a pH of 6 -6.5 or so. but under 7.

My opinion it's just reinventing the wheel when it's not necessary and in your case, all you really needed was to get a handle on the KH. I mean if you wanted to keep like cardinal tetras (pH 4.6- 6.2 ) or like Alcolapia alcalica (it's a cichlid from Lake Natron in Tanzania with a pH that goes from pH 9-12, pH 10.5 being the average) and there are other species with specific needs. Probably it makes sens to start from scratch on the water and put in what you need to get it where you want it in a controlled manner.
Also make sense when your water is so screwed up it's just easier to start from scratch and build it up than it is to try to break it down. Like if it bounces around depending on when you draw it, it would always be a different amount of adjustments needed, but starting with RO, it's always the same adjustment so when you have that dialed in, its the same process to build tank water after that every time and no variables.

​

I hope I'm good with just my tap water. My tap is KH 4, GH 4.

When I started the tank, I was using RO water...I thought that would be the best thing. Then I learned about minerals and switched to tap water.

My situation seems the best its been since adding the oyster shells. I re-calibrated the pH meter this morning and found it was a little high. Strange how before, the meter reading would bounce around a lot while holding it in the water...now it finds the number stays there.

Parameters of 4 dKH, 8 dGH, and 7.4 pH are suitable for many fish.

Your tap water appears to be in a range suitable for water changes. If you have to top off the water level due to evaporation, then using RO water is great as you do not add minerals. However, for water changes, RO water is unsuitable unless to add minerals to the water.

My tap water is horrible, so I use RO water, but I add Seachem Equilibrium to bring the dGH to 7 and I add buffering compounds to raise the dKH and pH. I target 7.5 pH in my tanks as they contain community species. I always used tap water until I moved to my current home where the water was so bad.

Thankfully it seems I have good tap water for this. I do condition and aerate it before adding to the tank. Out of the tap it's 9.6ph, 24 hours sitting on the counter, it's 8.4, an additional hour of aeration with an air stone brings it to 7.8. The LFS said this is because of dissolved oxygen and will likely change as the weather warms up. Water underground probably doesn't change in temp, but Lake Erie definitely warms up with summer temperatures.

 

pH moved to 7.7 this morning. I wonder if there's a point where I should consider removing some of the oyster shells. Given it was 7.3 yesterday at one point, this is probably just part of daily movements... I know the guidance for betta is 6.5-7.5... Small tank variability perhaps.

 

There's some fluctuation from morning when the lights come on to midday when the lights have been on.
I wouldn't worry about it unless you're above 8. Again the steady pH is the goal, not a specific pH. You can bring it down and have it stick if you need to once it's stable. The idea is to not go from 7 or 8 to 5, not necessarily to land at a specific pH number, just no more wild rides that stress the fish.

 

There's some fluctuation from morning when the lights come on to midday when the lights have been on.
I wouldn't worry about it unless you're above 8. Again the steady pH is the goal, not a specific pH. You can bring it down and have it stick if you need to once it's stable. The idea is to not go from 7 or 8 to 5, not necessarily to land at a specific pH number, just no more wild rides that stress the fish.

Thank you! My betta seems sooo happy. The pH is finding its own way now...I'm guessing it'll end up around 7.7 - 7.8...in line with my tap water. It appears I have stability now thanks to the shells in my substrate.

 

RO water is great for replacing water lost through evaporation. The water that evaporate is pure water leaving behind the minerals. Thus, using RO water that is also lacking in minerals replaces the water without increasing mineral content.

The pH of RO water is not relevant. If you measure the pH, it will normally be slightlay acidic because carbon dioxide dissolves in the water producing carbonic acid. However, because there are no minerals in the water to stabilize pH, if you stir the water, the CO2 will escape and the pH will go back close to neutral 7.0

 

Fish Tank Chemistry

The tank remains very stable. Little to no fluctuation in pH. KH is holding at 4, GH 8-9. Fish, Snail, and Plants are all very happy.

 

Awesome! You'd just want to monitor it with your water changes, look for the calcium carbonate depletion, which shouldn't happen for a long time, but, will eventually happen. you'll see KH drop from 4 or GH drop from 8-9 and keep heading lower bit by bit with each water change, not really ever coming back up and you'd need to add a new source of calcium carbonate. but that won't show up in your pH until that KH hits like >2 then you'll get the unstable pH again.

but yeah, this is like a year or more down the road. just something to watch for, you'll see it coming if you know what to look for. Really glad this solution is working out.

Can't help but notice the twice daily water changes, is there a problem there as to why you're doing that? and how much water are you changing each time? should be an easier way to work that. might be time to try a 25% water change, and work up to a 50% and see how those go with the buffer working. a single 25% will be just a bit more than you are doing daily, but a 50% would get you a day off. I just don't want you trying anything you're uncomfortable with until you've relaxed a bit from the last crisis. hahaha

 

Awesome! You'd just want to monitor it with your water changes, look for the calcium carbonate depletion, which shouldn't happen for a long time, but, will eventually happen. you'll see KH drop from 4 or GH drop from 8-9 and keep heading lower bit by bit with each water change, not really ever coming back up and you'd need to add a new source of calcium carbonate. but that won't show up in your pH until that KH hits like >2 then you'll get the unstable pH again.

but yeah, this is like a year or more down the road. just something to watch for, you'll see it coming if you know what to look for. Really glad this solution is working out.

Can't help but notice the twice daily water changes, is there a problem there as to why you're doing that? and how much water are you changing each time? should be an easier way to work that. might be time to try a 25% water change, and work up to a 50% and see how those go with the buffer working. a single 25% will be just a bit more than you are doing daily, but a 50% would get you a day off. I just don't want you trying anything you're uncomfortable with until you've relaxed a bit from the last crisis. hahaha

I updated the log to be more understandable. XX means 10%, X means 5% of water taken out before topping up. I'm doing only one water change per day. Depending on my Nitrate level, I do either 5 or 10%. The last couple days 10% because I accidently overdosed the easy green three days ago... I wanted just 2-3 drops, but ended up with a full squirt...the pump isn't smooth.

Now that I'm back to 20ppm on Nitrates, I might skip the water change tomorrow to see what happens. I take my readings before the water change, so I was at 20ppm before today's 10% water change.

Daily is really easy for me with such a small tank. I'm trying to give the tank as much consistency as possible. My aerated/conditioned tap water is 7.9ph, 4kh, 4 gh. Not too much different, so maybe could just do a bigger change and not throw it out of wack.