Hi Mike;

I don't know what happened to him, but "MountainStone"has disappeared, and is not responding to emails. I know he bought some of the stuff; I'm not sure if he ever followed through.

So it would be better to start a new thread. I can answer some of your questions.

1. Using cal hypo as described can coat the filter with calcium carbonate particles, which are themselves VERY susceptible to being stained. When you also create an oxidizing environment (from the chlorine) you make any metal in the water READY to stain. So what happens (at least some of the time) is that the metal stains the dust on the filter, rather than the plaster on the side of the pool. And, when you clean your filter, you actually (finally!) remove those metals from your pool.

2. We don't know that the CuLator is worth it. I'd hoped we were going to get a clearer picture from MountainStone, but so far, we do not have any confirmation that it works as advertised. We *think* it does; as described the mode of operation is plausble; but we still don't have definite proof.

Oh and for reference, here's the original thread:
Ascorbic acid treatment for stains, which sequestering agent to use?