Why do Inverts die do fast??

4 or 5 times now I have added snails, hermit crabs, emerald crabs, and other cleaner pack items. I acclimate them very slow in the dark with drip acclimation. I have taken several hours. I introduce them to the tank and they are dead within a day or two. I have not added much other than damsel because I don't want to kill off a lot of expensive fish. Can not detect any voltage in the water either.. I am not an expert, but have had other tanks with no issues and have somewhat of a clue, I hope. ANY IDEAS????? Starting to have algae issues.



ph 8.2

Nitrate 0

Nitrite 0

Ammonia 0

Phosphate 0

Calcium 400

Copper 0

Salinity 1.016 (It got a little low on me. Usually 1.022

Temp 73.6



90 gallon overflow with 20 gal sump, protein skimmer. cycling 900 gph

Lighting 54 led and 2- 48 inch actinic lights

Using RO water

85lbs live rock



Thanks

Craig