Hi again everyone,
It's been awhile since I posted a question, but I'm back. My tank is a 45 gallon, moderately-heavy planted tank that houses about 15 corys and a school of cardinal tetras (14 or so). Everyone's happy and the tank's been running since last August (I added the fish a few at a time, most recently 4 panda corys a few days ago).
consistent parameters: pH=6.6, ammonia=0, nitrite=0, nitrates=5ppm (it seems this is stable as long as I keep some DIY carbon dioxide running for the plants).
My problem is this: I wanted to do a 30% water change today after feeding frozen bloodworms yesterday and frozen brine shrimp today. I checked my tap water parameters first, and the pH is 8.0, ammonia is 0.25.
What should I do about the water change? Buy distilled water this time around? If I just do a 10% change, would that be ok? I've got new panda corys, like I said, and I don't want to stress them out.
BTW, fluctuating pH seems to be a common problem with my municipality's tap water. That's why I check it before I do a water change. Never seen the ammonia above 0 though.
Appreciate any help you guys can offer! Thanks in advance!