What caused low alkalinity in cycling tank?

[Brett S]

ok, so i just realized.. i was told not to use tap water to rinse or clean anything i used in the tank; I was told to use vinegar instead. Before I did my water change I rinsed the pyrex measuring cup (that i use to remove tank water) with vinegar to eliminate potential of any soap/tap water residue etc. from last time I used it. Could having some trace amounts of vinegar in the tank lower the PH in my 20g tank significantly?

This seems like really bad advice. I clean stuff with tap water all the time. Probably best to make sure things are totally tried before they go back into the tank, but frankly I don’t even always do that.

Vinegar can be used to help get rid of calcification on things, but washing and rinsing everything in vinegar is jut silly.