pH dropped 1 point

[Karen B.]

Yesterday I did a 25% WC on my 20 gallons - community tank, planted, temp about 75, kh 0, gh between 150 and 300, 0/0/10, 0 chlorine. (using aquarium co-op strip)

Population : 1 honey gourami, 10 chili rasbora, 8 false julii cory, 4 nerita snails.

A lot of plants had black beard algea so I removed them for a double seachem dose bath in a separate container. I also cleaned my HOB filter + my sponge filter (in aquarium water). I did however leave some hides and plants in.

My water is a bit milky today so I tought I crashed my cycle. Plus my fish are swimming a bit more toward the surface (but could be of boredom as the tank is more empty then usual). I retested my water and my pH, which is usually 7.4 / 7.6 is now about 6.4/6.6. I admit I don’t test it as often as the result are not working on the aquarium co op strip so the last readings of my pH was couple of weeks ago.

However my other tank, which I did not do a WC this week but last week, has its pH at 7/7.2 today (when it’s also usually around 7.4/7.6). so I tested my tap water and it’s about 7 (when it’s usually 7.4 or 7.6).

Should I do something about it? I know a lot of people say not to chase parameters but a pH drop of 1 is pretty significant. Will it harm my fish? Should I do another WC? Add baking soda?

[Colu]

Frist your fish swimming at the surface could be low levels of desolved oxygen.i would add an extra air stone I would also put some crushed coral in a media bag in your filter to provent pH swings

Edited July 11, 2021 by Colu

[Mmiller2001]

A pH drop of that amount wouldn't concern me. But a rapid shift in osmotic differences could be an issue. @Colu suggests an O2 issue, which is probably correct. Sometimes tap water can be low in O2 and high in co2.

A cheap way to test for osmotic differences is with a TDS pen. You would check TDS of your source water and tank water. If they are within 100ppm of each other, no problem.

Your stock is all software stock, I'd imagine they are enjoying the lower pH. The nerites might be a bit upset, but they can manage.