OK, I put in the polyquat and brushed again and it looks like there is/was some algae growing on the surface, it came up when I brushed. So I probably have both copper and algae. Since the last backwash before the 2- 10%chlorine gallons and the polyquat, the pressure on the DE filter has risen a few points; from the 20-24psi it usually runs, to about 29psi. That happens when it's gettng clogged I think, so it may be fitering out the dead algea. We will back wash again this afternoon after the brushed algea/whatever goes thru it for a while. We are adding couple inches of water at the same time as it went down a bit with the cover off so long; it's been pretty warm the last few days.

Then after the brush, and backwash, we'll add another gallon 10% liquid chlorine and keep the filter on and shut the cover for tonight. I'll test again in the morning.

We have 32oz of Leslie's Super Metal X which according to it's MSDS sheet is 2-phosphono-1,2,4-butanetricarboxylic acid (28%). Sound similar to the HEDP you mentioned, but not exactly. Do you think this is the same thing? If not, I'll get the HEDP.

We do have some pretty bad staining on the steps and a few other places, so I wouldn't be surprised that we would have copper in the water. Also the fill line is galvinized steel and does dump rust water for the first couple gallons. We hold a bucket under it until it comes out clear, but I bet previous owners may not have done that.

Those CuLator packs sound great! I don't care if they work slowly, as long as they get rid of the metal instead of just dissolve it. I'll get some of those too.

Since the polyquat and brushing all the algae(?)stuff(?) Copper(?) or combo has made the water cloudy, but I think it will filter out. So that's my plan until I get the test kit. Thanks again for the great advice. I feel like maybe we can get a handle on this now. And I now realize how lax we have been about maintenence. We fired the pool guy three years ago cause we caught him billing for days he didn't come, and ironically we're pretty much doing the same thing up til now. That's going to change.