Dead crabs, what gives?

[nine8taco]

Recently I havent been able to keep crabs alive. (hermits, and emeralds). all of my water parameters are good and theres a grounding probe in the tank. I feed a full cube of mysis every other day. 20% water change weekly. All other inhabitants are doing great. (snails, fish, sps, lps, softies and zoas) im kind of at a loss as to why they arent making it. When i buy them i usually just float them for a bit periodically adding a bit of my water into their bags and then dump them onto the sand and theyre fine (in my 7 years of reefing this has never given my the slightest issue) After I had a batch all die using this method I drip acclimated the next batch. Same thing.
Phosphates: 0 (but i have a decent amount of bubble algae so i know this is a false 0)
Nitrates: 0
Nitrites: 0
Ammonia: 0
Salinity: 1.025-.026
Temp: 77-78
Havent actually put a multi-meter in the tank but theres a grounding probe in it. (plugged into a grounded power strip, dont know if that could matter)
Anyone have any ideas?

 

[aKlevans]

Are you sure they are not just the molts?

 

[nine8taco]

Pretty positive (great thought though!) The hermits just sit on the bottom and never move, you can still see their legs sticking out. The emeralds I cant say are technically dead per se, i put him in and noted where I put him. I waited about 72 hours and he had not moved an inch so I assumed he had passed. I went to get him out and he was latched on to the rock. when he let go he latched on to my finger so i put him down on the sand where over the course of the next week or so he moved about 6" to my GSP rock and climbed up and hasnt moved since. This was about a week and a half ago, if he is still living i dont want to continue to bother him but ive never seen or heard of a crab taking that long to molt.

 

[Rob.D]

Have you been dipping your corals with Bayer?

 

[nine8taco]

Very astute rob! I dipped all of my rock and coral when I moved into this house. That was about 8-9 months ago though. Do you think it’s possible that’s still affecting it?

 

[Flippers4pups]

Very astute rob! I dipped all of my rock and coral when I moved into this house. That was about 8-9 months ago though. Do you think it’s possible that’s still affecting it?

Possible the rock could leach it out, but 8+ months later? It would take out your snails as well. Doubt it.

Have you pulled the hermits out to inspect them? If dead, of course wouldn’t move and smell bad as well.

Not saying you did anything wrong on acclimation, but inverts are usually very sensitive to water pramameters changes, especially osmotic shock. Question the LFS about the SG of the tanks the hermits and crabs came from to see if there’s a difference in their SG and yours.

 

[rkpetersen]

I'd send a sample to Triton to see if there is some contaminant in the water that the crabs are reacting negatively to.

 

[nine8taco]

Possible the rock could leach it out, but 8+ months later? It would take out your snails as well. Doubt it.

Have you pulled the hermits out to inspect them? If dead, of course wouldn’t move and smell bad as well.

Not saying you did anything wrong on acclimation, but inverts are usually very sensitive to water pramameters changes, especially osmotic shock. Question the LFS about the SG of the tanks the hermits and crabs came from to see if there’s a difference in their SG and yours.

I actually have tried that. I brought my water to them and had him test my water and his water both with his refractomer and his reading matched mine for my water and my water also matched the stores water 1.026-1.026

 

[nine8taco]

I'd send a sample to Triton to see if there is some contaminant in the water that the crabs are reacting negatively to.

I will absolutely look into this

 

[Flippers4pups]

Back to the dipping of the rock with bayer. Do you have any copepods or amphipods in the tank? Any shrimp?

In 8+ months of water changes, you would think it would be long gone by now. Did you rinse the rock well after the bayer bath?

Sorry for all the questions. Just puzzles me that just the crabs are dead and your snails are okay. Crazy. Any contamination that would take a crab, would take a snail, shrimps, copepods, amphipods, bristle worms.......

 

[nine8taco]

Back to the dipping of the rock with bayer. Do you have any copepods or amphipods in the tank? Any shrimp?

In 8+ months of water changes, you would think it would be long gone by now. Did you rinse the rock well after the bayer bath?

Sorry for all the questions. Just puzzles me that just the crabs are dead and your snails are okay. Crazy. Any contamination that would take a crab, would take a snail, shrimps, copepods, amphipods, bristle worms.......

I agree it is very weird! I definitely still have bristle worms. Haven’t seen cooepods in quite a while but I have a six line so I’d imagine he’s taking care of them. I did rinse the rock in old tank water before they went back in.

 

[Roggio]

I would pick up a cheap poly filter to see if there's metal leaching into your tank.

 

[nine8taco]

Well I don’t know if it’s THE problem but I found a problem. Tested voltage (black lead in wall outlet ground lug red lead in tank on vac setting, recently calibrated fluke meter) and I found .014 vac. That is until I took the ground probe out then I found 42 vac!!! I started unplugging components and one or two would drop it to 30 or 25 but the only thing that dropped it to nothing was to unplug the entire power strip that powers my tank. Where should I go from here?

 

[nine8taco]

I would pick up a cheap poly filter to see if there's metal leaching into your tank.

Will do!

 

[Flippers4pups]

I’m not an expert on stray voltage in our tanks, but I want to say that what your reading is okay. Most electrical equipment used in our tanks give off an magnetic field that can be read as “stray voltage”.

@Brew12 is our electrical guy.

I’ll see if I can find some more info on this.

 

[Flippers4pups]

https://www.reef2reef.com/threads/stray-voltage.304627/

 

[Flippers4pups]

https://www.reef2reef.com/threads/stray-voltage.293603/

 

[Flippers4pups]

If you have a piece of equipment leaking small amounts of electricity, saltwater corrosion on wires could leach copper into your water. Have your water tested for copper.

Inspect your equipment for damage and any metal around the tank for corrosion.

 

[nine8taco]

I know that I have a few small metal hooks inside the stand to help organize wires that are pretty corroded (but nothing crazy) and then a cheap little desk top fan on the inside of the hood to circulate air (hood is open in the back)

 

[nine8taco]

Based on those link I’d say it’s induced voltage I’ve never felt any voltage in the tank and my hand are always busted up I think I’d feel it if it was fault voltage