All my shirps, crabs and snails dead!

I dont know what is going on here. All my inverts have died in the last few days but my fish are fine!!! water test perfect! wtf!

 

You will need to post those "perfect" parameters to give us a chance to diagnose your problem. Most likely you have had a large swing in your salinity. If you are using a hydrometer I suggest you get a refractometer.

 

+1 2in10
You haven't recently used any copper-based medications?

 

Great question.

 

no copper-based anything...

nit 0 phos 0 ammonia 0 cal 400 mag 1400 kh 9 salt 1.026 and no swings

 

oh my, I just had a though. I put in a valve check with a metal spring. could this be it?

 

That is a real possibility.

 

Are you dosing anything?

I agree most common cause by far, siwings in alk, sg and pH.

Do you can a current pH value?

Introduce anything new to the tank?

 

i think that could be it. I did not think twice about it. No new introductions. dosing microbactor7 and reef bio fuel then of course my cal, mag and alk supps.