Right, it's worked as far as I can see, on the ones I've done no more palys
However I did have a slight disaster last night, as being a clumsy sod I dropped some kalk paste in the tank which somehow ended up in the powerhead before i could suck it back out.
This morning a couple of SPS corals have stripped a little at the base. DKH is only 0.5 higher than prev test, but I guess the fluctuation was too rapid, or maybe it peaked a lot higher. Worth it to be rid of the brown pest palys anyway I reckon.