Recycling Halimeda?

[cowrie]

Has anyone heard of a useful way to reuse harvested Halimeda from the tank?  We harvested a gallon volume of Halimeda and before we throw it out we were wondering what people do with it's calcium carbonate contents since natural sand is largely made up of Halimeda "skeleton".

[ReefMon]

Not only is it loaded in calcium, but phosphate too.

[michaelg]

On the reef it is a primary contributor to the sand substrate.  As glenn mentioned though, it would be loaded with phosphate to some extent as it is in the plant- though you could test this pretty easily to see if the phosphate can be extracted out of the sand by rinsing a few times with DI water.  It is going to take a whole lot of halemedia to get much sand though....  Just let it dry out, then crush it up to desired courseness.  Add some water to it, wait 24 hrs or more, then test the water for phosphate.  The phosphate might be pretty soluable and easy to remove- this is the question to be answered..... as the form of the phosphate would make a huge difference in if it will cause algae problems in the tank.