Another brown sand question

[Reefer911]

See pics below. The color seems to disappear when the lights go out. Acro tips are turning brown, and other SPS doesn’t do well. Tank is 10 months old. I have a 25w UV running at a low flow, closest guess is around 400gph.

Dosing: AFR, H2O2, and NP Bacto Balance

NO3 10
PO4 .08
Temp 77°
Salinity 34ppt
ALK 9.1
pH 8.1-8.3 ish
Salicate might be 0.1…definitely not more though. The sample is really light

It’s just a coloration on the sand. Nothing is there to siphon up.

 

[Reefer911]

Also, I have two MP40s at the back of my 47” Peninsula at around 50%. My Goni and torch tell me that flow is really good at the opposite end.

 

[Hallowhead]

How often do you clean sand bed ?

 

[Reefer911]

Usually every couple of weeks when I do a water change. But I did lightly stir the top a few days ago and it all came back

 

[Subsea]

Looks like diatoms. what’s in your clean up crew?

 

[Reefer911]

Various snails including trochus and cerith, if I remember the correct names. But they do bury themselves in the sand.

I had three sand sifting stars but I might be down to zero. There was one left a Al while back but I haven’t seen it lately, come to think of it.

Interesting that I’d get diatoms at this point. I recently increased the light intensity after changing my lights and discovering my old ones were too low. I figured this might happen so I set the Radions on AB+ and my Kessil on a blue setting at about 10% white. Honestly I figured there would be more of a blue look, although I do enjoy the full spectrum.

Maybe I should just ride it out and replenish some sand sifting stars

 

[Hallowhead]

If you added additional lights it definitely could be the cause.

 

[slingfox]

Looks like diatoms but most reliable way to diagnose is to look at a sample under a microscope.

 

[Reefer911]

Looks like diatoms but most reliable way to diagnose is to look at a sample under a microscope.

Everyone keeps saying this but I wouldn’t know anything more with a microscope than without! I’ve never seen any further explanation about how to distinguish one from another.
I’m pretty sure a friend has one so I am interested to learn what I would be looking for, or how to tell diatoms from dinoflagellates.