Major issue with my source water

[Jwgoff7772]

I did ask a similar question before my ph started to fall but I just got done cycling a 40-gallon breeder tank. The fish I'm keeping is one pearl gourami and 8 corydoras. My tap water ph after sitting for 24hrs is 6.5-6.8, KH is 0, GH is 0. I normally do 25% changes weekly but lately my ph has been getting as low as 6.0 at times and even doing 20% WC every 3 days I'm still getting a very low ph, assuming its the nitrogen cycle at work lowing my ph. I know that gourami and corydoras like a more acidic and soft water but my concern is my ph not being stable while ammoniaand nitrites are being broken down. I've read that your cycle doesnt function properly if your ph is too low and I've also noticed small ammonia spikes from from .25-.50 and I'm concerned that the ph drop even further at some point (like below 6) and dont want to ty and bring it up from an even lower numberand stress my fish. My tap has 0 ammonia and 0 nitrate. I dont want to use chemical buffers because I do not want to have to worry about getting the measurements correct every water change and also I used a chemical buffer in the past and sometimes I would need to add it one water change and not the next and never knew exactly when I needed to add it or how much because your other parameters dictate your ph as well. so I don't want to have to worry about keeping up with chemicals maintain my pH since corydoras have known to be really sensitive to shifts. I've done some reading about using crushed Coral in my tank in small amounts but I am concerned about my pH and gh getting too high. I've also read with the way crushed Coral dissolves it will actually stop breaking down once your water becomes a little alkaline. I just dont know if my ph situation is ok for the fish I keep and dont want my ph swinging widely since i have no buffers. Any help is much appreciated. I've been very grateful to you guys in this online community and I'm happy to be apart of it. this has been my favorite hobby to date and its communities like this one that makes it even more enjoyable. Thank you

 

[Colin_T]

Your pH is dropping because there is nothing in the water to buffer the nitric acid produced from fish food and waste and general fish respiration. Carbon dioxide from the fish and bacteria in the filter/ tank will also drop the pH.

Add some limestone, sandstone, shells or coral rubble to the tank. Add a small amount and monitor the pH over a week. If it is still dropping, then add a bit more.

You could also add 1 or 2 tablespoons of Rift Lake water conditioner every time you do a water change. It would add minerals like calcium and magnesium, which is required by all fish in small amounts.

Coral will continue to dissolve regardless of if the pH goes above 7.0. It reacts to the acids in the water and these are produced continually by fish and bacteria.

 

[Byron]

I have had identical conditions for 30 years now. I have gone down the "buffering" road but it is not something I would advise unless the fish species need it. And those you mention do not need it. However, there are some maintenance aspects to follow.

My tap water is near-zero GH and KH (GH at source is 7 ppm which is 0.5 dGH). The pH of the source water at the reservoirs is below 5, and they add soda ash to raise it to 7 so it has less corrosive effect on plumbing, but this additive dissipates out quickly. My 8 aquaria have been stable in pH for ten years now, since they started doing this (which was when I began keeping records to monitor it). Each tank has its own pH; some are around 6.2-6.4, others below 5. I let the tank establish its biological system and leave it alone. Provided you have soft acidic water species, this is not a problem.

When I did buffer back in the 1990's I used dolomite; aragonite is much the same. These contain calcium and magnesium, and buffer better than crushed coral which is not as good long-term. I did this by placing a nylon mesh bag of about 3-4 tablespoons of dolomite/aragonite in the canister filter. On my 90g tank, this kept the pH around 6.4-6.6 which was where I wanted it. This again was in the days when tap water pH was at 5 (or may have been less, I had no test below 5). I only did this in the large tank; the smaller tanks I left alone. I have primarily wild caught fish, and I have never had issues I could identify as related to the GH/KH/pH and most of the species spawn regularly and so far live normal lifespans so presumably they are fine.

As for the cycling issue, don't waste time fretting over that. Ammonia will be ammonium which is basically harmless, and live plants (even just some floaters) will handle this anyway. Nitrite will not be an issue, and nitrate should be low. I have never had ammonia or nitrite test above zero, and nitrate remains in the 0 to 5 ppm range and has for the last ten years (when I started regular testing) without any fluctuations. I change 50-65%, sometimes 70%, of the tank volume every week. Each tank has clearly established its biological system and it is stable. Fish suited to such water will have no issues.

 

[Jwgoff7772]

Thank you guys, I'll up my water changes to 50% weekly to see if I can keep a more stable ph that way. Just didnt want my ph getting below 6 and was afraid because I was getting close

 

[Colin_T]

I would add something to the water too, be it shells, coral rubble, aragonite, etc. You don't need much but you need to try and keep the pH stabile and this is hard to do with 0 GH and 0 KH.

You don't have to have lots of shell/ coral in there but some would help stop the pH fluctuations, and that is what kills fish.

 

[Jwgoff7772]

Ok, I'll pick up some aragonite on my way home. How much would you recommend for a 40 gallon breeder? 1/4 cup?

 

[Jwgoff7772]

And is my ph gonna keep rising until I remove it, ive read some ppl say it keeps it stable at 7.5 because it stops eating the acid once the water becomes more alkaline or will it continue to rise?

 

[Jwgoff7772]

I just realized your in Washington state, in in Arlington, wa. Wonder if your parameters are the same as mine? Thank you for you responses colin.

 

[Jwgoff7772]

Sorry about all the messages but just saw its Australia your from, not ththe states. I appreciate your time by the way. I'm definitely gonna take the advice and give it a try but like I said my only concern was if it gonna continue to rise past say 7.5 even with adding just a 1/4 cup, or would you say tea spoons? Because my ph last week was 6.8 and yesterday morning it was just above 6 so I feel I gotta try something.

 

[Byron]

Ok, I'll pick up some aragonite on my way home. How much would you recommend for a 40 gallon breeder? 1/4 cup?

I really do not recommend this. In my case, 3 tablespoons raised the pH from 6 to 7.6 overnight, and that was in a 90g tank.

You do not need to be buffering water for the fish species mentioned. Don't add complications, it is only risky.

 

[Jwgoff7772]

In your opinion Do you think my tank has a chance of a pH crash to below 6 in the case that I do not try to alter it other than with water changes? Because that's my main concern because I understand that the fish I have prefer soft acidic water but all I'm concerned about is a pH crash because API test kit is reading 6.0 and this happened within 2 days. My pH was between 6.8 and 7.0 on Sunday an this morning when I tested it it was 6.0. And like I mentioned my GH and KH are both 0 out of the tap. I'm using a AquaClear 50 in my 40-gallon breeder right now but I also have an AquaClear 70 that I was planning on using, do you think me using the stronger filter would help with my bioload and keep it from affecting my pH as much?

 

[Jwgoff7772]

I mean unless my api master test kit is a little off it seems my pH has dropped off quite a bit in just a few days 1 because, what is kind of strange is I also am using Tetra 6 in 1 test strips and those are telling me my pH is mid 6s , because I'm fine with keeping softer acidic water because the fish I keep in the fish I plan to keep prefer it but as I said I'm only concerned about it crashing to below 6. In your 30 years of fishkeeping has this ever happened to you?

 

[Colin_T]

A bigger filter (AquaClear 70 vs 50) will not make any difference to pH.

---------------------
Byron and I will disagree on adding some sort of calcium based substance (shell, coral, aragonite).

I prefer limestone to other types of calcium based material.

Personally I would add a small amount of material to the tank and monitor the pH over a week or two. See if the pH remains stabile at 6.0 or 6.5 or whatever it sits on. Then don't add any more.

You can test the substance to see if it 's going to raise the pH rapidly by putting some into a bucket of tap water and monitoring the pH over a week.

If the pH continues to drop after you add a small amount, then add a bit more. You want enough calcium based stuff in the tank to stop the pH dropping over a 2 week period. You can have some in the tank and it will stabilise the pH. If you have too much, the pH will go up. If you don't have enough, the pH will continue to drop.

 

[Byron]

I will answer your (Jwgoff) questions, first mentioning that I do not disagree with Colin on buffering, I only disagree that it is necessary for all fish.

I have never bothered over so-called pH crashes. The pH in my tanks does lower due to the normal organic build-up, and I suppose I partially counter this with my substantial water changes and keeping filters very clean. I do not know how low my pH is in some tanks which test at 5 but that is as low as I can measure it (the Tetra test goes down to 5, the API is 6). A couple of tanks remain in the low 6's. I do not care what it actually is because the fish come from such water. That is the important point. If you had fish preferring or requiring moderately hard or harder water, this would be a crucial issue obviously.

The pH in the Rio Negro, the largest blackwater river in the world and a major tributary of the Amazon, is in the high 3's to mid-4's. The river is full of fish. GH is zero, same with KH.

 

[Jwgoff7772]

Thank you both for your time and knowledge