Chlorine usage

[KRAMERK34]

like i was saying:
i just checked it this morning at 630 and got around 3 via dipstick, i just checked it again when i came home for lunch and didnt get any color change on the dipstick....
i'm baffled

 

[chem geek]

As shown in this manual the Hayward Aquatrol says it is for pools up to 18,000 gallons, but according to this page it says it produces only 0.87 pounds (0.40 kg) of chlorine per day (24 hours). In 18,000 gallons that translates to only 5.8 ppm FC per day or 0.24 ppm FC per hour. In your 14,750 gallon pool that would be 0.29 ppm FC per hour. With direct noontime sun, you could lose this amount of chlorine or a little more so the SWG could have trouble keeping up. This is one of the reasons one should oversize their SWG.

Nevertheless, your loss of 3 ppm over 6 hours, or 0.5 ppm FC per hour in spite of the SWG being on, is higher than one would expect. You really need a good FAS-DPD test kit so you can do an overnight chlorine loss test since that will tell you if you've got nascent algae growth or something else consuming chlorine in your pool. You can also easily verify the output of your SWG by measuring the chlorine level accurately after the sun goes down and then measuring it again early morning before the sun hits the pool. The difference in FC divided by the number of hours in between the readings should be around 0.3 ppm FC per hour less your overnight chlorine loss (which is measured with the SWG off).

Personally, I'd shock the pool with chlorinating liquid to a high level, though without an accurate test kit even your CYA reading might be off. Getting the good test kit is really the most important thing to do to truly diagnose this problem.

 

[KRAMERK34]

Thanks for that info Chem Geek, i am definately looking into getting my own test kit!