I wasn't sure what topic this went with! Chemical, water testing, structural?
I've had some mysterious staining in my pool. Several pieces of indirect evidence pointed to metals as the cause. The local pool store lady was stubborn about testing my water for metals, so I didn't actually get my water tested for metals. However, I observed a fading endpoint on the CH test, my pH had been very low (possibly causing corrosion of metal components in equipment), and vit C tablets faded the staining when dropped in the pool. So I used ascorbic-acid based stain remover and Metal Free, and the stains cleared up beautifully.
From what I have seen, tho, there is more staining stuff coming from the solar heater return! I didn't think there was any metal in that equipment, but the staining has the same properties as before, including the response to the vit C. I have actually SEEN discolored water coming from that return when I start up the booster pump (for the solar). Also it leaves a rather concentrated deposit on the step towards which it flows.
I would love some advice on this! Offhand I don't know the mfr of my solar heater/panels. I have some info on that, so I can look it up at home later. I don't recall whether I circulated water thru the solar panels while I was running the stain treatment. Maybe that would be the solution.
I am reasonably certain the metals (if that's the problem) are not coming from my source water. I suppose it's possible that some metal-contaminated water was in my solar pipes and didn't get the benefit of the treatment. It's hard to imagine that such a small volume of water could hold enough metals to cause this degree of staining, but I don't know enough to rule out that possibility. Another possibility, mentioned previously, is that there are metal components in the solar collection system which come into contact with the water.
Should I get my own metal testing kit or strips? (I really don't want to try the pool store again.) Does anyone have other ideas re: what could be causing this? My pH hasn't tested below 7.2 since I got plenty of alk in the pool, more than a month ago. I'd appreciate comments, suggestions, and/or advice.