arrow crab and hermit crab deaths?

[snappenin]

In the past 24 hours I have found my arrow crab and two hermit crabs dead with bodies intact. My water parameters are all within normal ranges. I have no predatory fish. I'm wondering if there's a disease that would affect only the crustaceans. I have a 65g DT and 20g refugium. I haven't added or changed anything lately with the exception of a sense anemone a week ago that I have since returned. Any thoughts?

 

[Betta132]

"Sense" anemone?
What exactly are the parameters?
Did the salinity fluctuate at all?
Did you pour water from the fish store into your tank?
What fish do you have?
Any other inverts?

 

[snappenin]

Sorry, should have read sebae anenome. I don't remember the exact parameters. I have my water tested at my LFS every other day. No problems with salinity but my PH was 8. I did a 10% change last night and added a buffer. Today it's 8.2. I don't pour water from the store into my tank. Fish consist of a blue spot jawfish, a long nose hawkfish, 2 black clowns, a vermiculite wrasse, a pj cardinal and a scooter blenny. I have 2 emerald crabs, 2 peppermint shrimp and a cleaner shrimp.

 

[snappenin]

Also found another empty hermit shell this morning.

 

[Calappidae]

IIRC hawkfish are predatory.. but more importantly what buffer were you using?

 

[snappenin]

I'm using Seachem marine buffer

 

[Calappidae]

Stop using it. Everytime you dose that it messes your PH up worse.

Ph is balanced by alkalinity, if your alkalinity is good, then your ph will be maintained more steady and swing less. That buffer your using on the other hand screws up alkalinity, fixes ph, and since it screwed up the alk, caused it to swing back to bad ph..

Just water change and honestly I know many experts who never bother to test their ph at all as outside water changes anything you do usually does more harm than good.

You can fix the damage the buffer caused by stop using it and just water change. It'll eventually catch up and balance out.

Now as far as your inverts are concerned.. you could've shocked them by bringing the ph up too fast. Arrow crabs especially do not like high ph swings. I don't know how you dosed it but if you raised the ph more than 0.1 per hour then that would explain alot. It's not the level the PH it's at that matters as much as how fast it rapidly changes.

Honestly if your ph is 7.8 (ideal range is 8.1-8.4) it's not worth panicing about and dosing (like I did) just bring it up slowly with a water change and you can almost ignore it from there. New systems also tend to naturally have lower ph while the filtration establishes more. IIRC nighttime ph naturally drops as well.

 

[snappenin]

Thanks so much for your help. I did a water change last night so maybe I will just let it be then. I was scared something more sinister could be lurking in the tank. My Leptastrea won't totally open, and I'm sure it's the low PH as it's done this once before. I get a little nuts and imagine worse case scenarios only because I care, lol.