GFO? for Randy

[Kenmx10]

Hi Randy, Im wondering, If GFO has the ability to lose particles back into the water because of equilibrium, What would happen if you put used GFO into a container of RO/DI water?

 

[Randy Holmes-Farley]

Copying from the other thread...

Phosphate will come off of GFO when placed in low phosphate water. I've done that myself and tracked the release, although I used reef aquarium water, not RO/DI. It probably works in RO/DI too, but may work better if there are other ions in the water to take the place of the phosphate as it departs the GFO surface (like organics, chloride, sulfate, bicarbonate/carbonate, etc).

 

[Kenmx10]

Thanks Randy, Im wondering more on the lines of how much release. Would it be enough to reuse. If it reaches equilibrium , if ro/do has zero p04, could you put it in a ten gallon aquarium of Ro water, let it release, then reuse? Or am I going the wrong way with this? Thanks

 

[Randy Holmes-Farley]

The answer depends on how much phosphate is on it, and how low you want to take it. If the tank is at 0.8 ppm, and you exhausted it, then you can likely remove a lot of that easily. Not all, but a lot.

If the tank is 0.01 ppm, and you want to remove that, then I expect it to take large amounts of water to remove a substantial portion of it.

Part of the explanation for that is that there will be a variety of different affinity binding sites on the GFO, and the strongest binding sites get occupied first. There is more to it than that, but that is the easiest part to explain.

 

[Kenmx10]

Thanks Randy, This info is very helpful and interesting. It could even save alot of money on GFO,as GFO cost a lot more than RO water. If I had the knowledge and equipment to do the testing myself, I would .

Sorry for the double post. I was not allowed to go back and delete one.

 

[Randy Holmes-Farley]

My concern is it may take salt as well as water to be efficient, and so may cost as much as the GFO, or more.

 

[Kenmx10]

You can get 5 gallons of salt for $35. 5 gallons of GFO cost $300.00.. How much salt would it take? Even if you only removed half the particles from the GFO, I would think at $300 a bucket, it would be worth it.

How can I measure the GFO particles to find out?

 

[Randy Holmes-Farley]

I do not know how much salt it takes, but I expect it takes a lot of salt water to drop the phosphate to very low levels on the GFO, less if you are talking about only removing the higher levels. You'd have to experiment to find out.