how much tin did you have ? how did you remove the tin? my icp test came back at a tin level of 298When stuff like this happens, it pays to have a ICP test done. Just do it so you can know for sure whats in your water that you might be missing. For me it was tin, had a crap ton of tin in my water and it was affecting my growth. Got rid of the tin, started dosing No3 and BOOM, my sps are taking off.
Also vendors... I love _____(don't want to give them a bad rep, because they are a good overall vendor) but their Acros were really bad a couple months ago. I lost 4 Acros to RTN/STN after a week of dropping them in my tank. I swicthed vendors for Acros and I haven't seen any losses yet. Just a thought.