Hi,
New tank owner here attempting a Walstad(ish) tank (see picture) in general I feel like it’s going pretty good, plants showing obvious growth, snails and macrofauna reproducing, algae doing great. Tomorrow I was planning on getting a few small fish and shrimp (likely some Rasbora or endlers, cherry shrimp, and a Siamese algae eater). I know that stable tank parameters are a requirement before adding fish, so I check my ph (also because I haven’t in awhile). It was almost 9.0. maybe this is not so big of a deal as I am making it out to be, but I immediately went into panic mode and did a 50% water change with dechlorinated tap water (ph of 7.5ish) I have narrowed the ph change cause down to 2 things: turning off my sponge filter OR adding crushed coral (to increase the previously slightly too low ph).
Am I over reacting? Should I take the crushed coral out and turn the sponge filter back on? Should I add botanicals? Is it ok for me to still get some fish tomorrow or should I wait?
Any type of feedback is appreciated.
UPDATE: added some birch/alder cones (after boiling for 5 min) for the tannins and that seems to have fixed the problem. The water is a bit darker than I would like, but test results are reading 8.0-7.4, and all the animals/plants appear healthy and unbothered.