Houston we have a problem

[Airborne 82nd]

My water department is in crises mode. Small town USA 4-6 people at the dept. 1 does the water testing the others work in the office. 2 of the office workes were fired so I can not get any help from them I heard everyone is getting a lawyer.
Now to my issue my tap and tank Ph has been about 7.6 for the last 14 months or so when I first got my tank. Now my tap is about 6.2 tested with api master kit and test sprips. Today is my 50% water change day so I am not sure what to do or how it will effect my Oscar and Pleco. My gut says do smaller pwc every day until they = out. I have no idea what could cause this tap water change or when it happened ( don't test as often as I did) but town is no help . Amonia 0 nitrites 0 nitrAtes 15
Thanks for any help

 

[Andy Sager]

You answered your own question. When there is such a disparity in water parameters, you do smaller water changes more often than larger ones less often.
The good news is that at 6.2, any ammonia is now less toxic ammonium so it shouldn't hurt the fish if it accumulates. Unfortunately, with the lower pH, nitrification will slow as well so there may be some die off of your biological filter bed. What you can do is keep water aside for water changes and increase aeration in it to get the pH back up to a more alkaline range.
As for why the change, your water company may have changed it's water source or changed it's filtering processes which were making the water more alkaline. If it were me, I'd be a little more cautious about using your tap water for cooking or consumption for yourself until the lawsuits are settled. It sounds like public safety is not high on their agenda now.

 

[Airborne 82nd]

Thanks Andy
How much do you think 25% 10% on the pwc? How many days to get the tank = to the tap? Not sure how much stress to put on Oscar.

 

[Andy Sager]

Thanks Andy
How much do you think 25% 10% on the pwc? How many days to get the tank = to the tap? Not sure how much stress to put on Oscar.

You're not trying to get the tank to match the tap. You're making the tap match the tank. This is why smaller amounts of water is better. Once you start aerating the water better, the tap water's pH should rise. Just make sure the other tap water parameters are similar to before.