Super high combined chlorine

[aylad]

Can i ask what the extreme case was that you needed to keep you FC at almost 40 for 3 weeks?

Yeah, if you really want to....The adult son of our next door neighbor committed suicide by drowning himself in my pool about 6 years ago, fortunately it was in October and at the end of the swimming season. In all honesty, shocking it at a much lower chlorine level for a few days would have been sufficient to make sure the water was clean, but it took about 3 weeks at extraordinarily high shock levels (and several water changes after that) to kill the "ick factor".

At the beginning of the next swim season I (overdoing it, as usual) called the head of the Infectious Diseases departments for our local 3 major hospitals and described the incident and my solution, just to make sure in my mind that the water was safe to swim in, and they all three actually laughed at me, said they'd drink the water with no problem and that my pool was probably the cleanest place in the state. Shocked it again after that, and THEN we went swimming!

I know this is no help to you, and like Watermom, I understand your frustration, but unless there is something introducing large amounts of "stuff" for the chlorine to kill every night, the only thing you can do it keep it shocked and it will eventually burn off. Have you tested it for ammonia lately?



Janet

[themaccs]

I am so sorry you had to go through that horrible event. And I guess you are right - no real help for my situation. But thanks for the encouragement. And again, sorry you went through that.

"but unless there is something introducing large amounts of "stuff" for the chlorine to kill every night, the only thing you can do it keep it shocked and it will eventually burn off"

Is there something that might be able to introduce large amounts of "stuff"?

No, I never really have tested for ammonia - kind of just assumed that is what I was dealing with and that I had to do the same thing whether or not I knew the ammonia level. I am kind of wishing I had at this point. Would a really high ammonia level have smelled like ammonia? I have smelled the "chlorine" smell, but not anything I would say smells like ammonia.

[aylad]

You wouldn't necessarily smell ammonia--but there are test kits that will check for it, and they're pretty cheap--look in the aquarium section at WalMart or any pet store. Since you're been fighting this long and it still hasn't cleared, I would check to make sure that's what you're actually fighting. I guess I have been assuming all along that we knew for sure that there was ammonia in the water. It's the only reasonable explanation that I can come up with right now, but maybe we need to verify it.....

Janet

[themaccs]

Tested for ammonia today - doesn't appear to be any. I questioned whether or not there was maybe a touch of green to my sample, certainly less than .25ppm, but Hubby said no way, there's no green in there - its just yellow! From what I have been reading, several people have indicated that the pool continues to eat chlorine well after the ammonia is gone. My experience certainly mirrors many of those I have read about, except that I can't seem to get it to end! The pool is unbelievably clear, don't think I've ever really seen it this clear before. I will be out of town Saturday - Wednesday, leaving hubby in charge of the pool - he has agreed to test morning, evening, and bedtime. Readings today were a little better than yesterday, but I still have an occasional CC just over 1.0 (otherwise 0.5 and occasionally just a hint of pink). And FC still seems to be disappearing at around 1ppm/hour - that may be a touch slower than yesterday. We'll see how tonight goes!

[chem geek]

When you were adding chlorine earlier, it probably was combining with ammonia to form monochloramine which is what you were probably smelling and would have had the CC be high. You are now past that point and the ammonia and monochloramine are gone and now you've got other miscellaneous organics that you need to get through -- most likely partially oxidized CYA that won't show up on any test.

You can see from my very brief history of this problem here that I started out with measured ammonia, then CC, and then a slowly dropping chlorine demand with little CC. I caught this conversion process early and mid-stream before it had finished.

Note that if you have any CYA in the water, then that slows down the rate of chlorine getting rid of whatever is left, but protects any FC during the day from breakdown from sunlight.

Richard

[themaccs]

Just thought I would update. We finally stopped losing chlorine overnight when I was out of town a week or so ago- figures I would do all that work so Hubby could have the fun of having the first good reading!! We totaled out at about 125+ gallons of bleach. I am now trying to figure out where to aim for with my CYA level - right now we are at about 55 and losing 5-7 ppm FC per day during the day (0 loss at night). The pool is in direct sunlight for at least 8 hours a day (maybe as much as 10) and for the last week or so we have been up into the 90s every day. I added 2 lbs of Di-chlor earlier this week to get the CYA to where it is now and we put 3 tri-chlor pucks in the chlorinator today to bump it up a little more. I am not wanting to add too much because we are going on vacation in a week and our plan is to bleach it up to a high shock level and fill the chlorinator - so we will be adding CYA while we are gone. We will also have someone check on things every couple of days (we will be gone 10 days). I'm thinking my goal will be about 70-75 for the CYA - I would prefer 60, but we are almost there and still losing a lot to sunlight every day.

Current Readings:
FC - 6.0
CC - 0.2
pH - 7.5
TA - 130
CH - 260
CYA - 55

[aylad]

Hi, and thanks for the update--we like to hear the end result after helping people with their pools--we all learn from it!!

I don't remember where you live, but losing 5-7 ppm chlorine daily is an awful lot. I'm in northwest Louisiana where the air temps are in the high 90s (heat index in the 105 range due to the 97%+ humidity), and my pool is in full sun from daylight to dusk--and losing 4-5 on a very hot day with a big bather load of kids is still a lot for me. I intentionally run my CYA at 80-90 ppm for that reason--with my weather conditions, I found that I lose much, much less FC during the day with it that high than with it lower. I'm one of the few that does this, but in my climate it's necessary. I lose 2-4 ppm on a hot day with a pool full of kids all day, and 94 degree water.

It's really a decision you have to make, because if you raise it to the higher levels and it doesn't work out for you, then you need to drain/refill to lower it...but then again if you're in a similar climate to mine, you might find that you don't lose nearly as much chlorine to the sun.

If you've got trichlor in the pool now, and use the chlorinator while you're on vacation, you're going to end up at around CYA of 70 anyway, so try it at 65-70, keep track of how much you're losing, and if it's less than you're losing now, you might want to consider going a little higher. Just keep in mind two things: 1) with the trichlor, you need to keep a good eye on your pH because trichlor will drive it down, and 2) the higher CYA works well in my pool because it's open year round--remember what the CYA breakdown did to your pool in terms of CC when you opened this year, and consider that in your decision. Might be worth it to raise CYA during the summer but drain/refill before closing it for winter, or at least set it up so you can keep chlorine in it during wintertime to avoid the ammonia problem again.

Janet