Little more research would have done us both some good. Yeah everyone has bad experiences. Mine just happens to be petco and I lost around $700 with them jokers.
The reason all your fish got ich was because throwing 10 fish into a tank at one time esp a 90g tank your asking from trouble. That is stress heaven there. 1 fish a month unless your buying same species. I am surprised you didn't have a full reef going in under 2 days a 90g is good for maybe 3-4 fish
Goto Petco you will find Popeye, Fungus, Internal and visible external Parasites such as worms, ICH out the wazoo, I went yesterday and the golder headed goby;s has extremely red gills (High ammonia I say) I had a fish die from petco in under a week and was told my ammo was high at .01ppm on a strip tester. Also their water nitrate is 10ppm and phosphate is 1.0ppm and thats "Clean water".
Petco is a laughing stalk IMO. But like I said we all have our opinions on stores and we all have been treated different. Also in saltwater a UV sterilizer wont do a thing for you unless you can slow it down to less then 50gph even then it may be to fast.