Mustang, this is interesting to me:
Side note, before I became a BBB'er and before this aforementioned AA treatment, I was sold on Phosfree by the pool store. It was on sale, too. I accidentally added it directly into the pool instead of the skimmer. A day later, I thought I had mustard algae because of a tan coagulated dust on the bottom of the pool. I can't say for sure if it was iron or not. It vacuumed right up though. I figured it was coagulated phosphates. Perhaps it was iron.
Re The MSDS on phosfree, yes, it's lanthanum.
I was referring to the phosfloc -- which is a different natural chemistry product, and is meant to be vacuumed to waste -- used only in very high phosphate conditions (mine are 25 ppm or 25,000 ppb, in other words, very high, and in my case, very high because water had been an abandoned swamp for 1.5 years...plus I use jack's pink every week for the iron, which then becomes orthophosphate when "spent").
UnderWater - this is an older thread from early in August. Whether the pool store tested fill water incorrectly or not re: CYA reading, RJ doesn't likely care, because his problem was apparently solved once he used the commercial phosfree AND phosfloc. I only revived the thread in an attempt to confirm that his results have held, because I'll be spending a boatload on it if I decide to try to floc my phosphate load down.
Alternately, H and I are discussing instead just doing a full water change in the spring and having it trucked in.
We had just discovered our softened water was NOT soft due to a plumbing error that was mixing the hard and soft water in the whole house. I HAVE a soft-water spigot to fill the pool, but we've been inadvertently running about a ppm of iron through EVERYTHING for the last 8 weeks. The system is now fixed and we are IRON FREE at the taps...so I will be able to refill/top up if I just change out the water in spring.
