Hi all, I'm new to the forum. I have a 85g tank currently housing 6 red devils, I want to switch to Africans (blue dolphin, electric yellow, acei). I know I need to increase pH - my plan is to remove the red devils, keep the water and filters running as is, remove the gravel and replace with pool filter sand and about 5kg coral sand/calcium carb & maybe add a bag of calc-carb into canister filter. Does this sound ok? Or should I empty the tank and start again? Will I need more coral sand to increase pH?