how old are your bulbs?

Rob - thanks for chiming in.

No I have not tested for silicates. Is it a Salifert test kit?

I have changed 3 of the 4 filiters on my RODI within the last 3 weeks. I did not replace the filter on top (is that the membrane? i think).

Tyler

My bulbs are 9 months old.
250 W DE
14K phoenix.

Still has a bit of life on it, but i won't dismiss it as a culprit being that it's reaching it's lifespan. I would agree that it might be silicates, I have never tested for it so I wouldn't know what to recommend. The way I dealt with my Dino problem was increased flow closer to the sandbed and a goby.

Yes, Salifert makes a silicate test kit. From what I've read it's the place to start in your battle with dinos. Is it only on the sand? You could always go bare bottom :mrgreen:

So if I test for silicates in my RODI and find high levels I replace all my filiters. But in my tank what is my next course of action?
In other words, what safely decreases silicates within a reef tank?

This stuff is not just on my sand but on my rocks, overflow and glass as well. If I blow off the rocks it grows back within 12 hrs.

I've read forum threads where people have used aluminum oxide phosphate removers (Phosguard) and reported good results. Aluminum oxide absorbs silicates as well as phosphates. I know on RC aluminum is said to be a no no, but as far as I know that is unsubstantiated. In any case I would research it before I used it.

Test first, silicates may not even be your problem.

you need complete blackness in the tank for 3 or 4 days. Pitch Black, and don't feed during that time. Large motorcycle covers work well.

Been 2 weeks. Still no progress. Got my PH up to 8.4 for a couple weeks now, syphoned out all dino's and did a 48 hr period of total darkness (towels). 3 days later dino's back in full force.

Todays tests were done at the LFS to insure my test kits at home were accurate. Today I tested for silicates in both my RO water and tank water. Test was extremely low (less than .03) to nothing. Nitrates and phosphates are still zero (never had any color register in my salifert tests).

Alk 9.5, Ca 450 and mag at 1400.