GFO tumble question

[Dan_P]

Once at saturation and given time t with no more phosphate additions, is any leached back out?

Does pH matter for the rate or saturation point of adsorption?

Following the above, can a change in pH trigger some level of desorption, or once adsorbed at any (common) pH, is the lower capacity fixed to the pH that saturation occurred at?

Do aquarists ever saturate GFO given the possibility that diminished adsorption rate looks just like saturation? Anyway, the questions remain about desorption and pH. Can I detect desorption before saturation? Also, does silicate displace/desorb phosphate or vice versa?

The chemisorption involves the replacement of hydroxide on iron with phosphate. I think there might also be a gain in alkalinity and pH which I could look into, though these effects are small.