Though I'm not sure if the bound phosphate will break down and source back into water column. I have used filters socks and skimmer to remove the particles. Also being bare bottom tank I syphon out detritus along with bound phosphate

No need to apologize and you asked some questions that other people are probably thinking about so I will do my best to answer them.

Yes, people use it in extreme situations. Several, including myself, have brought 200+ gallon tanks from 1.4mg/l of Phosphate down to 0.03mg/l with regular additions of Foz Down. As the Phosphate in the water drops the Phosphate in the rocks starts to be released. The Foz Down also neutralizes this. The situation of high Phosphate level in rocks is called Old Tank Syndrome.

It can be a permanent solution. That's how I use it.

Foz Down is a good replacement for GFO. Foz Down can reduce Phosphate levels to undetectable levels. Literature says 0.0015mg/l Phosphate. Since we need a little Phosphate in our systems Foz Down by itself is easily capable of doing what we need.

The instructions on the bottle say not to lower the Phosphate level more than .25mg/l in 24hrs.

I used chloride salt as an example. Foz Down is a chloride salt just like the Calcium we add to our tanks to keep the Ca levels up. Both are chloride salts.

To my knowledge there is no studies about whether it will ever release the Phosphate back into the system.

If we consider that Calcium chloride reacts with Alk in a similar way to Foz Down reacting with Phosphate ie flocs. Then since we know that once the calcium carbonate is formed(by the snowstorm(flocs) in the tank caused by Calcium chloride and Sodium bicarbonate) it doesn't dissolve unless your pH goes below 6.9(ie Calcium reactor pH). If the pH of your Display tank is lower than 6.9 your tank is on it's way out. Since Foz Down can be used on ponds as well as freshwater tanks which have a pH around 6.0 to 7.5 and it still works well. My belief from experience is that it will not release the phosphate if pH is above say 5. It may however never release the phosphate at all. No one knows whether it will or will not. Since our tanks are all over a pH of 5 I think the concern about releasing Phosphate back into the water column may be a false alarm from lack of scientific studies.

Another point I would like to make about Granular Ferric Oxide is that it is Iron based. I suspect that when you put it into your tank it releases Iron into the water? The HC-GFO I used to use went from orange/brown to black. We know that Iron fuels the growth of macro algae. Does anyone know if there is studies about whether GFO releases Iron into tanks and if the Iron released causes macro algae blooms?

Cheers,
Tim

I choose to use Fozdown as my tool for PO4 removal, if a tool is required. It's easy, no dedicated filter to run it, and I can stop and start as/if needed.
My goal as the tank progresses is to not need anything, but to help it along, I have a bottle standing by.
As the floc passes through the system, I would assume that the filter sock and skimmer will remove most of it. The rest, even if it does release back, would repeat the cycle (presumably). That said, still hoping not to need anything :)

Wow I'm sold. Gonna grab me a bottle to start in a couple weeks. :biggrin:

I also use Foz Down and find it's very easy to dose accurately, once it's diluted.
I dilute mine in a 4 litre container and dose daily through a Profilux doser.
I measure phosphorus once a week and adjust the Foz Down dose amount. Very simple. I have no worries any more about overfeeding the tank.

Also, GFO removes trace elements from artificial sea water. It's difficult to tell when the GFO is exhausted and is messy to change.

Here is an article on the effects of GFO on trace elements.:

http://www.advancedaquarist.com/2012/2/chemistry

.

There is a reference to what iron is released in that article I posted, Tim.

I've used it to bring the PO4 down then maintain with GFO. Thinking just moving to a continuous drip and giving up on GFO.

My success with GFO has been marginal. Although it's not necessarily all the GFO's fault. Usually I have the greatest of intentions of swapping it out regularly, and keeping it up for 6-10 months religiously. Ya right. I'm good for the initial getting it set up, then usually 2-3 months down the road I remember and think I should change it, and probably another month goes by because I rationalize that I just got it going a month ago, it should be good for a little while longer.
So needless to say I can't say I've ever even had a noticeable change in my tank. Somehow I've gotten pink cotton candy algae in my tank and if left alone it gets to plague proportions. I may have to give Foz down a try.

Thanks Mitch I'll look it up.

I was using just Fozdown for a while but found I couldn't get the dosing right using it just on it's own. All the problems I associate with GFO (namely cyanobacteria) went away when I was just using Fozdown, but I've never had to scrape my glass with a razor as often as I did when that was my only method of Phosphate control.

I've now switched to a GFO that's encapsulated in a polymer bead, which seems to mitigate a lot of the problems that come with GFO use, and use Fozdown supplementally if I find the rate of film algae growth gets to the point where I need to wipe the glass daily.