abysmal luck with snails & some crabs....

[backatitagain80]

Hello, this is my first time posting here, so quickly my name is Tim & I have had reef tanks in the past (5 year stint) and had a roughly 6 year break from them until last year when I set up my new 90gallon display with a 150gallon sump in the basement 2 years ago. I have had aquariums since I was roughly 12 years old when I started my first freshwater 30 gallon Oscar tank in my bedroom. I didn't experiment with saltwater until my mid 20's as they were far to expensive for a kid mowing lawns and raking leaves in the early 90's. I have a fairly good grasp of the bacterial cycle and water chemistry etc, but am at a total loss as to what keeps killing off my snails and "some" of the crab inhabitants I am attempting to keep...? My nitrates are barely detectible, zero nitrites, PH is stable, zero ammonia, phosphates are undetectable, magnesium in a good range, as is carbonate hardness and calcium. I have tested for copper, ran Polyfilter, tried using different GFO medias, Chemi-pure, Purigen etc, I skim with a Reef Octopus 200sss, use a filter sock I clean regularly, have probably 100-125lbs of live rock in the display and the sump, have Cheato in the sump on an inverse lighting schedule to my display tank, am using medium grain aragonite substrate and try to keep a fairly decent maintenance schedule cleaning nuisance algae, detritus and reactors from the display and sump. I also run a GFO reactor and carbon reactor with the proper flow through them. I have had my water tested by two LFS stores and they all said my water parameters are good as do my home tests. Salinity is 1.25 and temp stays around a stable 76 degrees. I run LED lighting for dawn/dusk and to get some better color & shimmer in the tank with main lighting coming from an ATI t5ho fixture. My salt of choice is Instant Ocean Reef Crystals that is mixed a few days prior to a water change in 40gal brute cans with all makeup water and evaporative replacement coming from a 6 stage RO/DI filter with a TDS gauge reading 0.

With those specs in mind, it is almost a guarantee that 90% of snails, emerald crabs and soft corals die quite rapidly when added to the tank? I am literally about ready to tear it down and start over if I can get to the bottom of this? I drip acclimate all livestock, have a Maroon clown pair in the tank with an overgrown Damsel and a Sailfin Tang and a handful of Cerith snails and red legged hermit crabs that seem to be doing fine?
Short of some advanced testing such as sending water to a scientific lab, I am at a loss as to what could be going on?

Any insights into what could be happening from a seasoned reefer would be more than welcome!
Tim

 

[Biglew11]

Snails need some algea to eat. also nitrates and phosphates should not be zero, nitrates about 5 10 ppm phospates maybe about .05 ppm. 76 is a little bit low but not bad go around 78 degrees.

 

[4tanks]

As above and I’d say probably starving and also they require very slow acclimation how long are you acclimating them