Shrimp deaths

[John Hughes]

I have a 60 Gal mixed reef that I've had up since this June. I've lost a cleaner shrimp within 24 hours, I think it was due to my swift acclimation. Just lost one of the two firecrackers I purchased 6 days ago, this one was all over the tank and eating like a pig and now he's on his back twitching. The other smaller one appears to be fine... so far.
I use RO/DI and Red Sea Pro salt, 10 gallon water change 6 days ago and my parameters are:
Ammonia 0
Nitrites 0
Nitrates 5
PH 8.2
Alk 8
SG 1026
Temp 78

Hammer
Frogspawn
Flower Anemone
Tomato Clowns x2
Starry Blenny
Yellow Tang
Yellow Watchman Goby

Any ideas on why would be appreciated.

 

[Dsnakes]

Any possible source of copper?

 

[Luu78]

Do you do any other essential element dosing that consists iodine?

 

[Luu78]

Are there still pods (copepods/amphipods) in your system?

 

[John Hughes]

Do you do any other essential element dosing that consists iodine?

I've read that there is plenty of iodine from several sources, food and salt for example. Water changes also help with this. So, no I don't currently dose Iodine.

 

[John Hughes]

Are there still pods (copepods/amphipods) in your system?

Yes, I don't currently have a fuge but when I rinse my sponge media I find many.