Diatom bloom

i have remove 2/3 CUC off my tank
currently have 10 Cerith, 3 Nassarius, 3 Nerite snails
i do have lit diatom bloom just around the live rock and part of sand around live rock
now my live rock have white powder stuff rusty stuff all over
i have seen copepods by the glass and heater before they are gone now after adding fish and snails
the PH buffer LFS give is maintain 8.3PH and raise alkalinity(they didnt tell me that)
i currently have API ammonia and Nitrate test kit
I just order reef test kit, i’ll get Calcium and alkalinity result in a few days
I add Koralia 2 in other side of the tank now
K2 output much flow then K1
Current have K1, K2 and mexijet1200 for skimmer
is it too much flow for 29 gallons tank?