is my sand toxic???

[klongo]

Help! what could be killing my snails and why won't my tiger cucumber clean my sand!
My sand looks horrible. It's not clean white - it's got a brownish algae on it - it's not slimy algae or red cyano - it just looks dirty. I added two queen conchs in my tank 2 months ago - never saw them again until two days ago when I found them both dead. I added a tiger cucumber about 4 weeks ago- he never leaves my rocks! My ceriths and margaritas are dying at the rate of about 15-20 per week.
My nassarius seem to be still going strong, my soft corals look great, my fish all look great. All water parameters are perfect except that my phosphates won't go below 0.2. I do not have a DI system or a phosban reactor. - my husband lost his job and I can't afford them right now. I have a refugium that doesn't really grow much (so not much export there). I feed rinsed frozen food 1 cube every day, i have about 12X turnover.
What am I doing wrong!!!!!????? and how can I fix it?

 

[malounsbury]

Sounds like you may be having a diatom outbreak. Are you using tap water? If so, you may want to switch to distilled.
Also, what are your other water parameters? Ammonia, nitrite, nitrate, pH and SG (or salinity)? Those numbers would help in making a diagnosis.

 

[klongo]

I'm using filtered tap water - can't afford an RO/DI (husband lost his job recently), but this has been going on for a few months?
Ammonia is 0, nitrite 0, nitrate <5, pH 8.3 to 8.4, sg 1.023. The only thing off is the phosphate at 0.2 which won't come down no matter what I do.
Would a diatom outbreak make my snails die? and my tiger not want to touch the sand?

 

[malounsbury]

I understand about the RO/DI unit, but you can go to any supermarket or walmart and get distilled water in 1ga jugs.
Are you able to post a pic of what it looks like? The diatoms should not kill snails, they actually eat them, and the cucumber should clean it off the sand also.
Are you running a protein skimmer? How often are you feeding your fish?

 

[malounsbury]

Also what type of sand/substrate is it? Do you have any live sand? And how deep is the sand bed?

 

[1journeyman]

High nitrates will kill inverts, but yours don't seem that high.
Has copper ever been used in your tank? That's always my first guess when someone is losing inverts for no apparent reason....

 

[mudplayerx]

Are you sure that you have a tiger tail cucumber? Are you sure that it is a detrivore? You might have a filter feeder cucumber and not know it. Those kinds don't eat sand. They can be identified by their filter feeder tentacles.