Couple inverts died a few weeks apart. Now Lobster dying?

Hello.

I had a small emerald crab die about 2 months ago. He was introduced to my tank at the same time as another emerald crab which is still doing fine, eating/molting. He died by flipping on his back and weakly moving his legs. He switched between that and looking normal for 2 days before he went lifeless.

One month later, the same thing happened to a porcelain crab, who was also one of a pair, of which the other is still doing fine.

I bought a small slipper lobster (1 and 1/2 inch) about a week ago. He is now doing the same thing. And I think hes dead, im leaving him in for one more day before I take him out.

Im trying to find the connection between these three deaths and there is one that stands out. These three died within a week of adding to the tank.

I acclimated by setting their bags into my water for 20 mins, then netting out and releasing into the tank.

My parameters are all pretty much perfect, 40 Gal Cube, no sump(canister filter). My fish and many many other inverts are doing great. I do have a feather duster that is not happy after having its host rock repositioned. I also have a Condi Anemone that hasnt looked very happy, but only in the last week.

I have my own RO/DI unit now. Am I still supposed to be using water conditioner with RO? Conditioner like Stress Coat, chlorine remover?? Cause I stopped using it awhile ago. And my roomate brought it up.


Thanks for any insight.

 

if you weren't using RO/DI water from the beginning, you may have copper or other toxins in your water... do you run carbon? If not, I would run it, and consider running a polyfilter too, to remove copper if it's there...

 

Shrimp and crabs are very sensitive to salinity and ph swings, I would check these out and no you don't need to be using the conditioners with RO/DI.

 

Thanks matter of fact I have been doing weekly water changes and my paramaters (home tested, plus weekly LFS sample checks at different LFS around town) seem good.

But I indeed have been concerned about salinity because I have a Coralife Deep six that reads 1.023 and a Red Sea that reads 1.026.

Both purchased at the same time.

 

the tough emerald crab is beating the other inverts..