| | Re: iron bonding to phosphate to reduce GSA
This is another good experiment waiting for someone to try it! Ms Walstad made the statement that algae, not growing on the substrate, can get iron only from the water. And, that iron has to be bioavailable - not bound to a stable anion. But, except for floating plants, all of our plants can get iron from the substrate. That surely suggests that keeping available iron from the water is one way to discourage algae.
For several years I managed to avoid any GSA, and I was always using twice the recommended dosages of phosphate. I was convinced it worked, but I had no idea why it worked. I didn't think of how easy iron and phosphate combine. I have no idea why phosphate didn't inhibit other forms of algae.