Why my fish & shrinps died in the rgugium

[wong jim]

Dear All,
See if you could help. My purple fire,fire shrimp & 2 cleaner shrimps died one by one starting day before yesterday in the refugium (24" x 12" x 18")which is connectd to the main tank (48" 24" x 24"). But all the fish , shrimp and snails kept in the 48" are OK. Could anyone tell me what's wrong?. I saw some sort of white bugs crawling all over the glass surface and probably on the sand surface, would these things bother the fish & the shrimp? Or the CO2 released by the grass in the refugium at night killed the animals? I'm really got stuck. Please do advise since I don't want any more killed in th refugium!

Jimmy WONG
from Hong Kong

 

[Anonymous]

The white things you see are probably copepods. They are harmless.

Do you have constant flow between refugium and main tank?

 

[wong jim]

Thanks JH. Yes, the flow is like this: Water falls into the sump by the drilled hole at the bottom and pumped back to the main 48". A cannister filter taking water from the main display to the 24" refugium and returned to the sump by the 1" plastic pipe by way of gravity. Guy on other web told me that the marco in the refug gone sexual might cause some problem. IF that's the case then keeping a refug is looking for trouble while its purpose is to reduce the NO3!?

Jimmy