Diatoms and Silicates

[shawtygotbass]

I have been battling diatoms since I set up this tank a year ago. Even the saltwater tank I had prior to this one dealt with diatoms I think. Mostly brown hairy algae, would stick to glass and sand as well.

It smothered out some of my corals!

I don’t have excess nutrients and generally run nitrate 1 to 5 ppm (closer to 1 normally) and phosphate about .06. Although lately I’ve been running it closer to .02 with PhosGuard.

My TDS is always 0 to 1, so I assumed there was no silicates. But I just heard that most standard RODI units only remove up to ~90% of silica, and it doesn’t show up as TDS. I’m still confused by this LOL.

I’m in San Diego and silica in SoCal tap water is 18, so I imagine 2ppm or more silica is in my system.

I ordered a test kit so can confirm what’s in my RODI water and DT tomorrow.

This leads me to my questions:
1. Assuming I do have silica in my RODI water, is there any way to remove it with a special DI resin or anything? I currently use the iSpring FD15
2. What silicates level is too much and contributes to diatoms?
3. Do I just need to perpetually use phosphate export media?

 

[Mr. Mojo Rising]

I'm not so sure its diatoms, possibly detritus or biofilm. Do you have any sand sifters in the tank? I do see one powerhead behind the rock, it almost looks like the front of the tank is the low flow spot where 'stuff' is deposited, maybe another powerhead will help.

IMO your phosphates level is really low and I wouldn't be using phosphate remover.

I don't really see algae in your tank that could smother out some corals

 

[shawtygotbass]

I'm not so sure its diatoms, possibly detritus or biofilm. Do you have any sand sifters in the tank? I do see one powerhead behind the rock, it almost looks like the front of the tank is the low flow spot where 'stuff' is deposited, maybe another powerhead will help.

IMO your phosphates level is really low and I wouldn't be using phosphate remover.

I don't really see algae in your tank that could smother out some corals

I’ll try another power head in the front left there. My tank uses 1 power head and and the return pump, and has a circular flow.
I wanted to add a second one anyways to be opppsite of that and make a more random flow.

Here’s a close up of the algae I had that made me start running the PhosGuard. This is from a month ago. It seemed like a hair algae of sorts. I started using PhodGuard, CUC, and lower lights and it’s a lot better as you could see in my pic from the original post.

But the stuff that smothered corals seemed to be a mix of the hair and this stuff you can kind of see on the glass in this other picture I added. It blows and catches everything. Attaches to glass and for some reason LOVES attaching ti green star polyps.