Re: Question about oxidized copper
Have you tried to get a read on your copper level? If its approaching .3 ppm, save yourself some hassle and do a partial drain if you're able. Then control the rest with sequestrant.
I've recently tried testing the copper level and it's either nonexistent or very low. There are a lot of questions concerning what has happened to the pool which is why I'm having to make educated guesses. The upshot of my guesswork being that there is/has been a combination of scale, copper and organics. The guesswork is based on the following:
* The green and blue-green color of the stains (indicating copper + organics)
* The high CH level (scale)
* Obvious rough plaster in places (scale)
* The oldest stains mirror where plant debris fell/settled in the pool (organics)
* The dark-then-light reaction of one stain to the Vitamin C tablet (copper)
* The copper plumbing in our system (copper)
* The fact that PG ran our pool at about 6.8 pH and one pipe eventually was so corroded it had to be replaced (We're now in agreement to keep it at 7.2) (copper)
* An incident which I still don't know what the reason was, but PG put something in the pool and shortly thereafter, there was both an algae bloom and green water. I've been thinking the green water was copper rather than algae since the limited algae we've gotten in the past has been powdery mustard algae that hasn't affected water color. (organics from algae + copper)
I may be wrong, but most of the evidence points to copper being in the pool in the past, and possibly still in the pool given that we still have copper pipes. However, I can't pick up the copper in any tests and we've been keeping the pH in the 7's.
Do note though, that if you use a sequestrant like Metal Magic when you have high ch, you will get a few days of cloudiness until it filters out...but that may help on the ch level as well
I've been wondering whether I should use a sequesterent when I can't get a copper reading in the water. That's partly why I decided to try Culater. Twenty bucks for a one-month supply seems like an inexpensive experiment (but may seem ridiculous in light of the zero/near-zero copper reading). Draining the pool is not an option at this time since we spent a fortune getting the pipe placed as well as in water bills when the pipe was leaking. We did get a partial replace of the water, however, as part of the pipe-replacement process.
The pool is very old and will eventually need to be replastered. In the interim, I'm basically trying to make it as aesthecially appealing as possible without spending too much money.
So, the question that comes out of all this is do I need a sequesterent given that there does not appear to be detectable copper in the water at this time.