Gfo quantity and quality question

USMA36 · Dec 23, 2023

I’m curious as to why Rowaphos recommends to use only about 1/8 what BRS recommends for their high capacity version. My understanding is rowa is the same thing as GFO but has not been recycled. My other questions are why does Rowaphos come damp and is it still as effective if it dries out?

CasperOe · Dec 23, 2023

Following!

Dan_P · Dec 24, 2023

USMA36 said:
I’m curious as to why Rowaphos recommends to use only about 1/8 what BRS recommends for their high capacity version. My understanding is rowa is the same thing as GFO but has not been recycled. My other questions are why does Rowaphos come damp and is it still as effective if it dries out?

Sime thoughts.

All GFO brands are probably the same chemical but the size and strength of the particles might not be.

GFO particles crumble easily and form dust when dry. Maybe storing it went cuts down on breakage by clumping the particles and preventing them from bouncing against each other and breaking.

gbroadbridge · Dec 24, 2023

USMA36 said:
I’m curious as to why Rowaphos recommends to use only about 1/8 what BRS recommends for their high capacity version. My understanding is rowa is the same thing as GFO but has not been recycled. My other questions are why does Rowaphos come damp and is it still as effective if it dries out?

The answer probably lies in the surface area of the particles.

I believe some forms of GFO have a higher surface area due to the internal structure of the particles, so that the surface area is greater than the visible outside area.

The higher the surface area, the greater the amount of phosphate that can bind to the surface of the particle.
The dampness of some brands (and related warning against allowing to dry out) probably relate to that structure.

In practice, I have found that some brands of GFO bind noticeably higher amounts of phosphate per gram.

Randy Holmes-Farley · Dec 24, 2023

Recommending less might also just be a marketing thing or a more conservative approach. I have no reason to think Rowa is more potent.

I also do not know what the recycled comment relates to as I doubt any of the commercial products are recycled.

I expect most brand are made by the one or two large industrial suppliers. Phosphate binding is an after thought. The big market is arsenic binding of potable well water.