What is this?!

[Taralynn23]

It started about a month ago and has progressively covered all the sand in the tank. All of the fish and corals are thriving.

We added PhosGuard and dosing phosphates (a week so far)

We added silicate filter to RO/DI system

Didn't change light system - have had a Kessel AP9X for about a year now.

Any ideas? We have dealt with dinos before, it is not on the rocks and no air bubbles.

Alk - 7.6
Calcium - 386
Mag - 1450
Phosphate 0.02
Nitrate 8.5
Salinity 1.026

Only thing added was algae scrubber in the sump about 3 months ago

 

[BryanM]

phos almost undetectable, if these go away at night, then it is likely dinos. And with the recent addition of an ATS, could very well have bottomed out phos, .... Which is how I got dinos.

 

[Taralynn23]

phos almost undetectable, if these go away at night, then it is likely dinos. And with the recent addition of an ATS, could very well have bottomed out phos, .... Which is how I got dinos.

It's just weird because it is not anywhere on the rocks, we had dinos a long time ago but it used to be on the rocks as well when that happened ?

 

[BryanM]

It's just weird because it is not anywhere on the rocks, we had dinos a long time ago but it used to be on the rocks as well when that happened ?

Mine started on the sand, and as it got worse it definitely got on the rocks and glass. It is horrible.

 

[Taralynn23]

Microscope picture of a sample from the sand

 

[lmfbs]

Look like diatoms to me.

 

[tripdad]

+1 diatoms

 

[Taralynn23]

+1 diatoms

Any ideas on controlling them? We have tried dosing Phos, increasing current, and now doing water changes. It's only on sand bed nothing on the rocks and corals are all fine, and we also removed silicate from RO and that's clear

 

[Üter]

Did you test for silicates in RO water?

 

[tripdad]

I have had luck outcompeting them by dosing bacteria( low dose). Doesn't really make sense as it is blamed on silicates but it has worked. Getting flow across the sand is really important also.