Filter for FOWLR & Aggressive Tanks?

[davidfrances]

I am having some problems with a brown snot like growths in my 250G Marineland DD tank. I have it stocked with larger angels, tusks and tangs. The tank is 18 months old.

My water parameters are good:
NH3 & NO2 - 0.00ppm
NO3 - 0.00 - 5.0 ppm
Phos - 0.00 - 0.03 ppm
pH - 8.4
KH - 10
ORP - 350-410

I complete a 20% water change every 2-3 weeks when the NO3 increases to about 5ppm.

I used a Skimz 251 skimmer with ozone set to inject when the ORP falls below 400. I run the skimmate a little wet.

Not sure what is causing the snot algae. I don't have the classic red cyno, although I suspect the brown snot is a type of cyno or diatom. I brush it off my rocks and sand, and run a Fluval F6 canister for a few days every couple of weeks in between H2O changes to try and export some of the brown snot.

I am wondering is anyone uses supplemental filtration and if so what type?

Any ideas?

 

[Cu455]

What do you have for circulation? More flow might help.

 

[SDguy]

Those are impressively low N and P numbers for a FO. I would double check your results by maybe having the LFS also test.

That said, I agree that more flow may help. What sort of lighting do you run? Is this a FOWLR or just a FO? Also, can you get a picture of the algae, might be helpful to ID it.

 

[davidfrances]

I run two (2) MP60's. My return pump is an Eheim 1260. With this level of flow, I already have problems keeping my sand in place, so I doubt that is the problem.

The tank is lit with four (2) Reef Breeder Photon 24's w/120 degree optics.

I had a LFS double check my N&P readings, and they came back with the same results. I suspect that much of the P is bound up in the algae and thus undetectable in the water.

Will post photos later.

 

[davidfrances]

Some photos:

 

[azjohnny]

That does look a lot like diatom algae. Are you using an RO/DI filter for your top off and to make saltwater? Not using one can produce silicates

 

[davidfrances]

That does look a lot like diatom algae. Are you using an RO/DI filter for your top off and to make saltwater? Not using one can produce silicates

Yes, I am using a RODI. the output water reads 0 ppm. I just replaced all the filters, including the RO membrane. The tank next to this one receives the same water and doesn't have this problem