silicate in water?

Tank info: 135 gallon DT, 45 gallon sump with a 30+ working volume, 0 ammonia, 0 nitrite, 5ppm nitrate, 8.2PH.
I'm dealing with a diatom bloom in my saltwater aquarium. The tank is 3 months old has 100 lbs of (formerly) dry rock and 140 lbs of caribsea live sand. I'm certain it's diatoms because of the ease with which it comes off when brushed, like a fine brown powder. I use tap water that's conditioned to fill and do water changes on my tanks. I have a 65 gallon fresh water that's been set up for over a year and never had a diatom problem once. The tank has gravel, one live plant, and three comets. I've never tested my water for silicate but would have to imagine there's little if any since the fresh water tank is brown algae free and always has been. My question is if it's not the water could it be the rock and/or sand? If so, would this diatom problem eventually resolve itself or should I consider a reactor to remove the silicate? I would like to get coraline algae to grow but my lfs says with having ambient light on the tank I'll probably always have the brown algae. He showed me one of his tanks that receives very little ambient light and the rock was still covered in brown. I'm a bit discouraged since the tank can't be moved to a darker local. At least not easily. Sorry for rambling on and bouncing around,but am trying to resolve this issue and there seems to be a lot of variables involved. I did cut back on the lighting intensity and duration which has slowed down the diatom bloom. What to do....? Any help would be greatly appreciated!! Thanks

 

Bump!

Bump!

Ken:;ghost

 

I'm going to say it's the tap water. When I first started my reef I used tap water and had algae like you wouldn't believe. I finally purchased a R/O unit and switched to using R/O water in my reef and have had almost no algae issues since.

 

I'm dealing with "new tank syndrome" on my newly set up 180g which is what your describing, (around 2 months running now) and expected the diatoms, they do go away! Cut out the silicates and you get rid of the diatoms in large part though easier said than done. As said RO/DI is one way (and strongly suggested anyway on many levels), just let the diatoms consume the silicates till gone unless your replacing them with your water changes, or even a product that claims to work though I've never needed to use is Chemi-Pure Elite that some people like. Many snails also remove silicates but you will probably want to look into using RO/DI to start and take it from there. Remember that Saltwater takes ALOT more patience and research than Freshwater but the payoff will really blow your hair back. Enjoy your research...later!!!

*i'm curing a lot of live rock in my tank which is adding to the problem but fine with me...i'm patient .

 

Thanks for the replies. I understand that RO/DI water is the way to go. It is an investment I do plan on doing at some point. However, if it is my water why wouldn't I have the same problem with my freshwater tank?