Rust colored sand ?

[ilovemytank]

My sand has started getting a rust colored top to it. Any ideas how to solve it ? The tank; 3 years old, nitrites, nitrtates, ammonia and phosphates test as close to 0 as you can get. Alkalinity tests high and for some reason my calcium test wouldn't work. I can stir it up and it will be rust colored again in 5-6 hours. Started about a week ago. The same sand sifting gobies that have always been in the tank and I haven't seen this before. It's not red slime or anything like that. It does seem like all of a sudden I have lost a bunch of hermit crabs. Everything else in the tank is awesome. Sorry the pictures attached are junk. Advice ? Oh yeah-last water change about two and a half weeks ago- 50 gallons.

 

[meowzer]

Hey...how ya been?
it is more like a brown? I know you have a cuc, but do you have nassarius or cerith snails? Maybe try a fighting conch.
OH...how old are your lights?

 

[mech-a-nic]

A Diamond Goby will clear that right up.

But more flow will too.

 

[ilovemytank]

Hi Meomzer !
I have the same cuc fpr a long time. It consists of several nassarius and cerith snails as well as two diamond gobies. I'm woundering if this could all stem from the high alkinity - maybe causeing a break down in my calcium. My test for calcium didn't work but maybe thats because I'm experiencing a break down. Also why all of a sudden does it seem like I ost alot of hermit crabs ? Anyone ?

 

[flower]

Originally Posted by Ilovemytank
http:///forum/post/3100252
Hi Meomzer !
I have the same cuc fpr a long time. It consists of several nassarius and cerith snails as well as two diamond gobies. I'm woundering if this could all stem from the high alkinity - maybe causeing a break down in my calcium. My test for calcium didn't work but maybe thats because I'm experiencing a break down. Also why all of a sudden does it seem like I ost alot of hermit crabs ? Anyone ?

Hermits have a short life span...also they need bigger shells so they can grow. If you are down on hermits it will explain the brown algae on your sand..hermit crabs love to eat the brown algae.