it could be dust from the new rocks or sand, ect... your
pH could be off hard to tell without a test kit, or it could just be bacteria bloom which will be the good ones that you need for your tank to cycle. 25% water changes daily should help clear it up make sure to not pour water in to fast , avoid disturbing the substrate should help. some fish like
goldfish will never have clear water no mater what you do... i see you have platies,, they are big Bioload producers like goldfish meaning they poop alot... you will need to vaccume the gravel frequently at least once a week. i only have 2 and i vaccume the rocks every other day with 25% water changes.. seems like all they do is eat and poop it will take a few days to get the water to clear up but be patient it will get there..