Did a 50% water change on Sunday and turned my CO2 back on today, had it on really low. CO2 had been off for a few days to let my shrimp acclimitise.
Tested my PH and it's dropped down to 5.7, KH is 0, GH is 6.
Not sure what's gone on, I did my normal water change, RO water with Salty Shrimp...