how much chlorine should I need each day?

robl45

Well-known member
Oct 27, 2007
918
Parkland, FL
hey guys, my salt water generator died and without funds to fix it, I'm back to liquid chlorine. I am doing the method talked about on here to get rid of the algae thats built up for the past month as I've done a few times before when the SWG quit working. Anyway, as I've never run on a continuous basis with chlorine, my question is, how much chlorine should I add each day assuming the pool is 12000 gallons? I have 2.5 gallon jugs of 6% chlorine. Should one jug last a week, a month? This is south florida so algae tends to come quick. stabilizer is around 110. I overshot the last time i put stabilizer in. PH is right around 8.
 
With CYA (stabilizer) at 110 you're going to have to keep your FC level really high. According to the Chlorine/CYA chart it's going to be between 7 and 12. I know you have an SWG but since it's not working you're going to have to consider your pool a non-SWG pool and adjust acorrdingly. If you can't have the SWG fixed or replaced in the near furture you might want to consider draining and refilling your pool to get the CYA level down to about 50ppm.

Having said that there are several things that affect how much FC you'll lose a day. Such as, whether you cover your pool or not, what your person load is, how many hours a day your pool is in full sun, etc. I live in South Alabama and with a CYA level of between 40 & 50 I use about a quart of 6% a day during the summer.
 
Everyone's pool is a little bit different. It all depends on the level of organic crud that your pool tends to have introduced or developed, along with the amount of driect sun on the pool, the temperature in the water and out, etc. So there is no real way to know how much you will need. I would say that it is best to start out with a couple of jugs of bleach on hand.

How are the rest of your numbers right now? If your FC is high, that may account for your pH reading 8.

Yes, your CYA is high at 110, even for an SWCG pool. You might want to take steps to change some water out and that way, you won't have to maintain such a high FC.
 
well I hope to go back to SWG in the next few months, so I'm hesitant to drain it. But I thought I need to keep it at like FC of 3. So more like 7-10 I want to keep it at? good thing someone mentioned that or I would just have algae all the time. The pool gets sun all the time and is not covered. temperature I guess is usually around 86 or so.
 
Get your ph down closer to 7 and your chlorine will be more effective, but also be aware of how high chlorine affects ph readings.
Make sure that you kill all of the algae, do the overnight loss test. Having a higher CYA just means that your shock level is increased, your daily target level is increased, but, it also means that your long term chlorine usage will not be as high (thats is why SWG makers recommend higher levels.) :mrgreen: Make sure that you test at the same time each day, and that you NEVER let your FC drop below the target level (it will be lowest each day after the sun is off of it.) I think that you might find that once you wipe out the algae and establish your target level, you can maintain it with ~ 2 or 3 cups of 6%/day, or you can dose it higher every other day (so your 2.5g jug should last for at least 10 days.) Just make sure that you test it at least every day, and NEVER let your FC drop below your target.
Also, you may want to look at adding an algaecide, like borates for long term, or a poly-quat for short term. Once you have your ph (and TA) down lower, if you then add borates, it will help stabilize the ph, a big plus for when you get the SWG back.
Good Luck, and Best Wishes!
 
With CYA around 110, you can add chlorine once every other day or once every three days, but I doubt that you could go an entire week. You will end up using a little more chlorine this way than you would otherwise, but not too much.

The goal when adding chlorine is to never allow the FC level to fall below 8 (give your CYA level). Typically you test the FC level and then add enough chlorine to raise FC up to somewhere around 12 or 14, so that by the next time you get back to the pool in two or three days the FC level will still be at least 8.
 
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