View Full Version : GFO Article.

11/06/2004, 02:41 PM
Hi Randy,
In the November, 2004, article of ReefKeeping Magazine, in your article entitled Iron Oxide Hydroxide (GFO) Phosphate Binders (http://reefkeeping.com/issues/2004-11/rhf/index.htm) you wrote...

Interestingly, the concentration of phosphate, in marine sediment pore waters whose sediment is iron oxide hydroxide, appears to be controlled to a great extent by phosphate bound to the iron.

Even more importantly, this bound phosphate is still available to the water column by exchange, so the sequestering is temporary rather than permanent.

This fact may be unimportant in an application where the GFO is presented and then removed with its bound phosphate, but in other applications, such as mud substrates or GFO accidentally released into the aquarium, it may become more of an issue.

Does this mean that the PO4 can become unbound and released back into the water column?
If so, is there a time approximation before it happens?


Randy Holmes-Farley
11/06/2004, 03:43 PM
Yes, all such processes are equilibrium processes, so can reverse to some extent. The actual binding and release is not so much a time concern. It is always happening in both directions, and just reaches an equilibrium with a lot on the GFO. I don't think that folks should worry too much about it in the context of using GFO, but when bacteria start to coat the GFO, some of the phospahte may be released to the bacteria or the water column.

11/28/2004, 09:33 AM
I have something that may be a little off-topic to GFO article, but it is based on phosphate removal. There is a product I have come across called PO4-Minus. It is made by Korallin, a German company and distributed by Bayside Aquarium Supply, Inc. The explanation that comes with the product is incredibly vague, but it claims to "reshape" PO4 into something that can be exported by a protein skimmer. I thought you might have some interest in this, and I am certainly interested in anything you might have to say about it.


Randy Holmes-Farley
11/28/2004, 04:01 PM
I've not used it and am not certain what exactly it is. I don't like to recommend things that I do not know the ingredients for (and hence do not know the risks). I'd suggest asking in the main forum what experiences folks that have used it have had.

12/02/2004, 07:43 PM
Thanks, always appreciate your dedication to the people on this website. Happy Reefing.

Randy Holmes-Farley
12/03/2004, 08:36 PM
I'm glad you find it useful. :)