what causes this???

[a&m aggie 04']

i always have to clean this brown stuff off my glass. My tank has been up and running for over 6 months now. I used RO water, it looks like diatoms-- but what causes this??
My lights are on about 9 hrs.
I know ill get a need the test results before i can tell you, but what chemical causes this (phosphates?)

 

[a&m aggie 04']

how do i get rid of them???

 

[nacl-h2o]

Actualy silicates are one of the things that pass in number though the RO process. The DI stage of a RO/DI is what removes much of the silicates in that filter. If your silicates are high in your source water they are probabaly coming out of the filter lower but still to high. Levels of silicates and phosphates to name a couple found in RO water from areas where they're high in local water is the reason many use RO/DI. They sell media that will help remove them. I know Seachem Phosguard will remove phosphates and silicates and I'm sure there are others.

 

[bang guy]

Dan is right on. Your RO membrane is only removing about 70% of the Silicates and fish food is a readily available source of nutrition for Diatoms (pre and post digestion). RI will remove 99+% of the rest of the Silicates if you use a RI unit after your RO.
Diatoms, although unsightly, are a primary food source for many filter feeders and snails. You shouldn't (and probably can't) completely eliminate them. More snails will help, but how often do you need to scrape off the Diatoms?

 

[a&m aggie 04']

every few days, i start to see a little. I was using RO/DI at 1st but then i switched to RO b/c it was alot more convenient to get. Ill just have to start getting RO/DI again, no prob. As for the snails, i think mine are all dead (get sucked up in my powerhead) and ill go get some today. Are Turbos the best for cleaning up diatoms?

 

[iechy]

I have the same thing and as was stated it is just what gets through even after the filtering. I just scrape the glass every two days and it hasn't become a big problem. But like Bang Guy said if they provide a food source for some of my livestock then it's not entirely bad.