having trouble with low pH

[somethingclever]

Hi All,

I have a heavily planted 10 gallon tank that's been running for 6 months (4-glofish tetras, 6-guppies, 2-otocinclus, 1-snail). Fish and plants are all doing well. Nitrates are usually close to 0. I add liquid food as needed to bring it up a bit. My tap water has 0 kh, 0 gh, and low pH (usually around 6). I've been adding seachem equilibrium to keep the snail happy, this has been working to keep the gh up. I was adding baking soda to bring up the kh and keep the pH around 7. The last time i was at my LFS I got some "API ph up" figuring that maybe it was safer / better than baking soda. When I add it to the tap water and test I see the expected increase in kh and pH. However when I add this water to the tank it seems to have the opposite effect on the pH. Testing the water after adding the new water shows very low pH (off the chart), and 0 kh. It is lower than both the existing tank water and the new water. I did several water changes to try to raise the pH with "ph up" before switching back to baking soda. Does this make sense to anyone? My chemistry is very rusty.

[xXInkedPhoenixX]

What kind of filter do you use? If you use a hang on the back this is a good spot to put crushed coral. If not you can still place crushed coral in your tank. In simple terms as the water gets more acidic it will break down the coral and bring the pH to a more neutral level. This is a more stable way of achieving a pH in the 7s. Constant fluxuations with chemical solutions isn't great for your tank as you've likely deduced. It will bring up your GH too, but my tanks don't seem to mind that so much. I just put my crushed coral out of view along the back at the top of the original substrate. 

Edited October 25, 2021 by xXInkedPhoenixX

[Beardedbillygoat1975]

I second @xXInkedPhoenixXwith the crushed coral. I think you’re asking for trouble adding all these different supplements in the tank. 

[somethingclever]

On 10/24/2021 at 10:51 PM, xXInkedPhoenixX said:

What kind of filter do you use? If you use a hang on the back this is a good spot to put crushed coral. If not you can still place crushed coral in your tank. In simple terms as the water gets more acidic it will break down the coral and bring the pH to a more neutral level. This is a more stable way of achieving a pH in the 7s. Constant fluxuations with chemical solutions isn't great for your tank as you've likely deduced. It will bring up your GH too, but my tanks don't seem to mind that so much. I just put my crushed coral out of view along the back at the top of the original substrate. 

Thanks for that suggestion. I have a hang on back filter, it's the stock one that came with the aquarium kit. There's not much room in the back but I did scrap the original filter media and charcoal after watching the Aquarium Coop video about upgrading filters. I put on a pre filter, and put the extra 2 prefilters in the hang on and added as much coral as I could in the remaining space (only a small handful). I didn't see enough of a change with the coral which is why I started with the baking soda. Maybe I can swap out one of the filter pads in the box for more coral. Putting the coral on my daughters purple substrate will be a problem 🙂

I was keeping things pretty consistent with the baking soda. My experience with "ph up" is really baffling me.

[xXInkedPhoenixX]

Yeah there may not be a lot of room for much of it. How long ago did you add it as it does come up gradually. You might want to get a mesh filter bag and fill that, either do as you suggest, make room in the HOB or even just put it behind a plant. I have quite a bit of it in some of my tanks which run sponge filters. 

Edited October 25, 2021 by xXInkedPhoenixX

[somethingclever]

I put the coral in about 5 months ago (before I added fish). I guess it's hard to tell if there was eventually a change because I've also been using the baking soda. I'll make those adjustments. Maybe I'll also test with putting coral in a jug of tap water and see how long it takes to change it.

[xXInkedPhoenixX]

Yea I would definitely try the coral solution otherwise you'll be constantly adjusting and I can attest to the fact the fish aren't usually happy with that. I have a friend that does that with her 40 breeder and whenever she adds fish they don't survive the constant changes (but her resident fish survive I guess they're used to it). I put some in a cup and hid it with subbwassertang in my 4 gal tank just last week, it's going to take a bit for it to come up just because the flow isn't going over it as it would in an HOB.

You probably didn't have enough to make a difference. 

[Hobbit]

I also have very soft water, and I use both crushed oyster shell and baking soda (as well as potassium bicarbonate or calcium carbonate, depending on whether I want to raise the calcium or potassium level a the same time). The crushed oyster shell gives me a great safety net, but no matter how much of it I dump in there, I still end up needing to supplement. 

I use oyster shell instead of crushed coral because I have chickens and had the oyster shell laying around anyway.

I’m not sure why the pH up would be affecting your tank that way though. I don’t know what’s in it so I couldn’t say why it might be doing the opposite of what it’s supposed to.

Can you do this test: get some of your aquarium water straight out of the aquarium with a clean glass or plastic container. Then test the pH+KH, add the pH Up, and re-test. I’m curious if it’s being affected by something in your aquarium water or by something in your aquarium, like your filter or gravel.

[tolstoy21]

I’ve used both crushed coral and Seachem alkaline/ acid buffers + equilibrium  to good effect in these situations. Crushed coral is a longer term, slower acting, acting solution.  The Seachem products are very good for mixing into your change water, much better than something like ph up. My preference these days is crushed coral for tanks I have something to put it in, like a box or hob filter. 

Edited October 25, 2021 by tolstoy21

[somethingclever]

On 10/24/2021 at 11:43 PM, Hobbit said:

I also have very soft water, and I use both crushed oyster shell and baking soda (as well as potassium bicarbonate or calcium carbonate, depending on whether I want to raise the calcium or potassium level a the same time). The crushed oyster shell gives me a great safety net, but no matter how much of it I dump in there, I still end up needing to supplement. 

I use oyster shell instead of crushed coral because I have chickens and had the oyster shell laying around anyway.

I’m not sure why the pH up would be affecting your tank that way though. I don’t know what’s in it so I couldn’t say why it might be doing the opposite of what it’s supposed to.

Can you do this test: get some of your aquarium water straight out of the aquarium with a clean glass or plastic container. Then test the pH+KH, add the pH Up, and re-test. I’m curious if it’s being affected by something in your aquarium water or by something in your aquarium, like your filter or gravel.

I tried your suggested test. The pH in the test water increased the expected amount. I’m really curious what happened initially but probably won’t be able to figure it out. I guess I could run similar tests with tank water but include gravel, decorations… till I can find the source of the problem. I guess I’ll stick with extra coral and baking soda for now. I’m reluctant to try the seachem in case it causes the same issues. Thanks for all the help.

 

[Hobbit]

That’s very interesting! I guess something in the tank is absorbing/reacting with the pH Up. Hopefully crushed coral and baking soda will work better for you.

[quikv6]

I have similar soft water with no KH, and decided to have livebearers before I knew any better. I have been using baking soda for the better part of 2 years now, in addition to having crushed coral in the gravel and HOB filter.

If sticking with baking soda, I have found that consistency is key:

1) Measure (change in KH/PH) exactly what X amount does to X volume of YOUR tap water.

2) Try to change the same volume of water each change.

3) When changing water in large volumes (I don't think this may apply to you, since you have a 10 gallon tank), I mix the total amount of baking soda in a separate 2.5 gallon bucket, and pour it in slowly, consistant to the volume of water refilling from the Python/Tap. This seems to maximize consistency, and minimize the chance for drastic fluctuations.

[somethingclever]

@quikv6

Thanks for the suggestions. It's good to hear multiple people say that baking soda is a viable solution for low pH issues. The internet is so confusing. One thing I really like about Cory's videos is the amount of gray area he admits there is in keeping fish. Could baking soda kill your fish instantly? Yes. Could they live forever with baking soda? Yes.

I've already been following your 3 tips for working with baking soda so this is reassuring. I've been doing 20% per week. Probably not needed because my nitrates are always low, but it's a nice routine and lets me spend some time looking at the tank.

I can't say enough how nice this forum is. Everyone is so knowledgeable, respectful and positive (in my limited experience).  I've become addicted to this and am already planning my text tank.