Quote Originally Posted by PoolDoc View Post
As far as 'out of service' -- I would only anticipate it being out of service for a couple of days while you were treating it with the ascorbic acid. None of the other things would be incompatible with swimming.

Let me contact Chem_Geek and Marie, and also, I need to get the chemical info page posted, so I can direct you to the exact products you need.
You only need to stay out of the pool during the time the ascorbic acid is working to remove the metal stains. The reason is that ascrobic acid will remove all the chlorine in the pool so it will be unsanitary during that time. Usually the stains will get removed within a day or two, sometimes in a matter of hours (depends on how old the stains are). Ascorbic acid works better for iron stains; not as much for copper stains.

So you would let the chlorine drop somewhat on its own before adding the ascorbic acid so you don't waste so much money on having ascorbic acid just get rid of the chlorine (you wouldn't let the chlorine drop much below Ben's minimum FC chart, but you can let it certainly get to or slightly below that minimum). If your pH isn't somewhat on the lower side (definitely below 7.5) then lower it. Then add enough ascorbic acid to get rid of the FC and have extra left over. One pound of ascorbic acid in 10,000 gallons gets rid of 5 ppm FC. So any excess beyond the amount needed to get rid of the chlorine will be used to reduce the metal stains and get them into the pool water.

The ascorbic acid will also lower the pH more which is part of how it works (it's also a reducing agent). Once the stains are gone then you'll add a metal sequestrant that has HEDP such as Ben referred to. That will keep it in solution at least for some time -- it breaks down over weeks from chlorine, but fortunately not as quickly as EDTA-based metal sequestrants that break down in days to 1 week and create a much higher chlorine demand. After you've added the metal sequestrant and had it circulate for an hour or so, you slowly add chlorine and can also slowly raise the pH over time. You can swim as soon as you've got the minimum FC level from Ben's chart for your CYA level. If the pH is still on the low side, that's OK for swimming since it's not horribly low.

As for the CuLator®, you can add that packet anytime into your skimmer, but normally would add it after you've added the metal sequestrant. The CuLator isn't fast, but will remove (absorb) metals even when bound to metal sequestrant. It will take weeks of circulation to remove most of the metal and if there is a lot of it then it could take more than one bag though as Ben points out if there isn't very much then a bag could be used again at another time.