Last week I had 2 cherry shrimp die suddenly. I checked water parameters and they were all good, though I didnt have a GH/KH test kit, so I ordered that and checked it and they were alright too. I figured maybe just old age, and went on about my day. Today I came in to another dead shrimp. I have a heavily planted tank with kuhli loaches, so there could be more--these ones were towards the front of the tank where I can see. No damage seen on them, just dead. Any ideas?!
Other tank info: 29 gallon, lots of plants, 7 glofish tetra, 7 kuhli loaches, 3 adult endlers, 3 adult platys, 5 nerites, 9 adult malaysian trumpet snails, 15ish adult cherry shrimp. Variety of babies of endlers, platys, and trumpet snails. Running 2 Aqueon quietflow 20 filters
Water Changes: It's been about a month, I generally just test parameters and top off water as it evaporates, about 2 gallons per week.
Temperature: Ranges from 76-78 F
pH: 6.8-7.0 (color looks a bit in between the two)
Ammonia: 0
Nitrite: 0
Nitrate: 0, maybe 2? (I know, my plants are hungry...)
GH: 5
KH: 2-3 (kinda started to change after 2, was definitely changed at 3)