WOW!, one puffer in a 55, IMO, is overcrowded. I hope that these are valentinis and not dogs or porcs. If this is the case I hate to say it but your in bad shape. You should remove ALL the puffers in that tank, might be able to get away with one small puffer for a little while but they are messy eaters, aggressive toward eachother and it gets worse with age. This is more like a holding tank at the lfs than a show tank, if left as is this is DEFINITELY a time bomb. even with the LR and bacteria your trates are going to skyrocket overtime , mostly due to the puffers and with those fish you cant get a cleanup crew as they will become part of the waste causing trates because your puffers will eat them. With high trites the least of my worries would be killing the liverock as you risk killing the fish and what happens when ich rears it ugly head becasue the fish are stressed due to bad water quality. Cant treat the main tank with copper due to the LR. IMO, remove three of those fish (preferably the puffers) or get a 100 gal. minimum. These fish will not last where they are.