Hi Matthew;
1. Add a box of borax -- slowly, to the skimmer, with the pump on -- and 4 gallons of 6% bleach or 2 gallons of 12% bleach this evening.
2. Test your chlorine level tomorrow AM, and again tomorrow PM
3. Repeat the borax doses, till your pH is above 7.2
4. Continue the bleach doses, till your AM FC levels is more than 12 ppm AND your CC levels is less than 1 ppm
5. Skip bleach doses if your chlorine level in the PM is more than 6 ppm.
The FC = 0.2; CC = 0.4 suggests you have a fair amount of oxidizable goo in the water. It could be a little or a lot; it could residue from bacterial biodegradation of stabilizer, or it could be cheap algaecide used last fall. There are two ways that I know of to get a handle on this:
(1) you could take your water to a EPA certified lab, and have them do a COD test (Chemical Oxygen Demand) done for $$$. Then you could convert that to a estimate of total chlorine needed.
(2) you can dose with chlorine till you can (a) hold a residual overnight and (b) have a low CC relative to your FC.
I recommend the 2nd option . . . since you have to DO the same thing, in either case. Even if you know how much you have to oxidize, you could damage your pool if you try to add 125 ppm FC to your pool all at once. The only reason I mention it, is that we currently have several poster in similar situations, who are frustrated that their chlorine keeps disappearing, and that we can't tell them when they'll be done.
Let us know when things seem to stabilize. You'll also need to think about how you want to chlorinate over the summer. One possible combination -- especially if you can conveniently by FRESH 12% bleach, and have a way to carry it without messing up your vehicle (it's VERY corrosive) is to shock with bleach 1x per week and use trichlor in the skimmer or a floater in between to hold chlorine levels.
Good luck!
Bookmarks