Super high combined chlorine

[chem geek]

It does sound like you are near the end. Just keep in mind that the easy stuff that oxidizes readily has been taken care of, but there may still be some remnants of partially oxidized CYA that will be somewhat slower to oxidize and get rid of. You are definitely close and should see your total chlorine demand go way down at this point.

So if your CYA is low, raise it so that you don't lose too much from sunlight during the day. You should have it at least at 30 ppm, but 50 ppm is fine as well and is more typical for pools in the sun (pools in a LOT of sun, such as Arizona, sometimes operate at 80 ppm to minimize chlorine loss, but you have to be very diligent about maintaining chlorine in such pools since it takes more chlorine to shock them to get rid of algae).

It's interesting (and somewhat comforting to my nerdy personality) that the total amount of chlorine needed was in the ballpark of that predicted based on the CYA loss, which was a rough guestimate to begin with.

Richard

[themaccs]

So if your CYA is low, raise it so that you don't lose too much from sunlight during the day. You should have it at least at 30 ppm, but 50 ppm is fine as well and is more typical for pools in the sun (pools in a LOT of sun, such as Arizona, sometimes operate at 80 ppm to minimize chlorine loss, but you have to be very diligent about maintaining chlorine in such pools since it takes more chlorine to shock them to get rid of algae).

It's interesting (and somewhat comforting to my nerdy personality) that the total amount of chlorine needed was in the ballpark of that predicted based on the CYA loss, which was a rough guestimate to begin with.

Richard

My CYA was at 40 when I checked it earlier today - I had to use a little stabilized chlorine yesterday morning when i ran out of bleach. So it looks like I am good there. We do get a lot of sunlight on the pool, so I will have to see how that goes once I see whether or not I am loosing any at night. I think I will be able to get home mid-day tomorrow to check on it.

I am still loosing a bit of FC, just added 1 quart + 3 1/2 cups because it had fallen to 14.5 and the CC was back up a little over 0.5. But it is nice to be adding bleach using my pint measuring cup rather than by the jug full!

I can appreciate the comfort you receive from knowing your guestimate was in the ballpark - my personality works the same way.

The cloudiness in front of the light in my pool is nearly gone as well! YAY!!

Thanks again for your support and encouragement - not to mention your willingness to share your knowledge and experience!

[themaccs]

Well, i am still fighting, but perhaps not quite so hard. FC dropped from 15 last night to 10.5 this morning. CC was at 1.0 last night, up to about 1.5 this morning. I added 1 1/2 of the large (182 oz) jugs of bleach (so about 275 oz). Rest of my numbers look like this: pH - 7.2, TA - 150, CH - 200, CYA - about 45. I plan to come home mid-day to check on it.

[aylad]

Sounds like you're almost there. You'll know for sure when the Cl stops dropping overnight, when tested in the evening and again in the morning before the sun hits the pool. Just a note--I'm one of those that keeps my CYA intentionally 80-90 because I live in Louisiana with my pool in full sun all day. If I keep my CYA below 60, I lose almost twice as much chlorine during the day as I do with my CYA at 80. It's an unusual case, I know, but I'm just saying it happens.........

Janet

[themaccs]

Mid-day not too bad - FC - 11, CC - just over 0.5 (1 drop almost cleared it). So another jug and 1/2 of bleach (about 270 oz). Seems like i haven't really lost much more FC between 6:30 am and now (1:10 pm) as I did between 11:00 pm and 6:30 am this morning - almost the same number of hours, but a LOT of HOT Sunshine today.