Bro, bro...Talking about sugar, I have tried it for my 4ft tank (450L)with 3 spoon of sugar. it takes 24 hrs to clear and skimmer skim like hell.
The good thing abt sugar, it will bring NO3 down, from my observation, if u dun continue to dose, the LS might be afftected in the long run (not sure why, but it happened). So the husbandary of reefing still the best.
Yes, PH will definitly drop but it will be back, maybe the shocked killed ur fish. Moreover, 1 teaspoon to ur tank is too much.
Take care now and dun be sad. Continue the reefing, the rewards will be achieved in the long run.
Cheers!