best way to reduce phosphate?

[bongobrian]

My phosphate levels are reading out at 0.5ppm consistantly. I need to get it down!! I recently started a refugium full of caulerpa which is lit 24/7. It's only been running for about a week and I know I probably need to let it run for at least another week before I can see results in reduced phosphate. Does anyone know if the refugium should be enough to get my phosphates down to 0ppm and keep them down? I heard that dripping kalk is also effective in reducing phosphate. It's something I've never done before, but perhaps this would be very beneficial to my tank. Can someone tell me why dripping kalk gets rid of phosphate? I heard or read somewhere that it causes phosphate to precipitate out of solution. Does it have to do with PH? thanks for any help.

ps. Yes I am using RO/DI water ;)

[Randy Holmes-Farley]

If a refugium has enough growing caulerpa in it, it will certainly drop the phosphate levels low enough.

Limewater may or may not reduce phosphate, but it likely isn't a cure all for levels as high as yours. Here's an article that discusses phosphate, and also how limewater might impact it:

http://www.animalnetwork.com/fish/li...&RecordNo=2481

[Barry N.]

Randy, I enjoyed reading your page regarding Phos.
but can we ever rid them as it can be in just about everything we use?

I have been fighting to rid my system with Phos. I now rise my food in RO/DI water but come to find out the other day that my R0/DI water has 1.0 ppm of Phos? I called the manufacture and they said that it could be the membrane. I jsut about stopped using flake food as I know that has lots of Phos. in it.

Is it also true that carbon will also leach Phos. into the system if used too much?

Anyother advise?

[bongobrian]

Randy-Holmes, I read your article once before but thanks for posting it again. I didn't remember reading the section about limewater. I have a question, if I can keep my ph around 8.4-8.6 using only ph buffers, will it have the same effect on phosphate as what limewater supposedly has causing phosphate to precipitate? I know it's just a hypothosis, but is the precipitation caused just by the ph level? or is there something else about limewater that makes it do that? A couple days ago I added some extra buffer to my system to get the ph up to 8.6 and it seemed like the phosphate level dropped significantly from about 1.0ppm to 0.5ppm. This goes along with what your article said about people with micro algea preferring to keep the ph a little higher. Hopefull between the higher ph and my refugium, it will get the phosphates down to 0.

This brings up one more question. I've been thinking about putting in a DSB of fine grain sand. When would be the best time to add the DSB so that it doesn't have the "reverse" effect on phosphates and create a resevoir for the phosphate? should the phosphate level come down to a certain point before the DSB can be added? thanks much.