Are these Dino's or Diatoms?

[magicjosh]

Hi all,

I recently got a couple of trochus snails and a strawberry conch to deal with some brown algae. However 48 hours after adding the trochus snails, 3/4 died and the last living one is not doing well at all. The conch is doing fine and has been slowly eating away at all the brown algae.

I asked around about this and was suggested the brown algae might actually be Dinos and not Diatoms as I originally thought, and that Dinos are toxic and will kill snails. I wasn't sure about this because the conch I bought has been eating this brown algae all day and seems to be thriving in the tank.

I am using RODI water with 34 PPT salinity. I have test kits for ammonia, nitrate, phosphate and alkalinity and all of them were within normal ranges except for nitrate which is 0 (which is probably due to and causing all my algae).

I have other inverts in the tank (a nasarrius snail and a pistol shrimp) and all of them have been fine as well.

When I blow the algae with a turkey baster, it forms a dust and doesn't get stringy. It also persists throughout the night.

Is there anything else I am missing here besides actually buying a microscope to examine them? I can't figure out why all my trochus snails died so fast and suddenly, but all my other inverts are doing great...

de

 

[taricha]

the answer isn't obvious, but some snails may be more selective than others and trochus graze on rocks which the strombus will be in sand. There may be different nuisance algae on the two surfaces.