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Thread: Just getting started and have a chlorine demand problem

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    Smile Just getting started and have a chlorine demand problem

    Had chlorine demand problem. Looking at test kit chart have little over 12,000 gal pool. Put 1 gal of bleach yesterday am and 2 gal at pm. Current ph is 6.8. Current chlorine is at least 5 or higher. Looking for a cheaper solution than making local chem company rich. (test srip from them as of today still showed no chlorine. Above ground pool, 2 hp sand filter that has run almost nonstop for past ten day. Water is crystal clear and stat as of last week. CYA as of 5/31 - 70, 6/3 - 100. What is my next step. God's answer to prayer finding this site!!!

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    Default Re: Just getting started and have a chlorine demand problem

    Hello and welcome! We are glad you found us and thank you for becoming a subscriber. Some pools open in the spring with a high chlorine demand that you think is never gonna end and then one day it does. The answer is to keep shocking the pool and keep the chlorine consistently high. How high your chlorine needs to be depends on your CYA level. Since yours is 70, then you need to shock it up to 20. Test as many times a day as you can and each time add enough bleach to get back to 20. There is no such thing as testing/dosing with bleach too much. The more often, the faster you'll be done. In a pool this size, each quart of 6% bleach will add about 1.2ppm of chlorine. Once you get the chlorine level to hold overnight without losing more than 1ppm of chlorine, then you can let the cl level drift down. With a CYA of 70, you'll need to keep your chlorine between 5-10 all the time or you'll risk an algae bloom. Don't use any trichlor pucks or dichlor shock powder as these are both stabilized and will cause your CYA to continue to rise, and you don't want that! Just stick with bleach.

    You're going to need to get a good test kit. Cheap test kits cannot measure chlorine levels as high as you are going to need to run. We recommend the Taylor K-2006 or 2006C which you can find in the Amazon link in my signature line. If you buy through the link, the Pool Forum makes a little money on the sale which helps us to keep this place going. Until you get the good kit, you can use a dilution method. Not super accurate, but better than nothing until that good test kit is in your hands. More about that here:

    http://www.poolsolutions.com/gd/how-...d-testkit.html

    Another issue that you have is that you need to get that pH up above 7.0 ASAP! Any reading below that is acidic and can damage your pool. Test kits cannot differentiate below 6.8, so your pH may be much lower than that actually. You can use 20 Mule Team Borax (laundry aisle at Walmart) to raise it. It is added slowly to the skimmer while the pump is running, breaking up any clumps. Start with a half a box. After a few hours, retest and redose until you get it between 7.2-7.8. High chlorine levels will give false pH results, so the best thing for you to do, is to get the pH in range before you start shocking the pool.

    One last comment --- a 2hp pump is HUGE for this size pool. Sometimes too large of a pump causes things to blow right through the filter instead of being trapped in the sand. I have a 24ft AG and I have a full-rated 1/2 hp inground pump on my pool and it is plenty big.

    Come back with more questions and keep us posted of your progress!

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    Default Re: Just getting started and have a chlorine demand problem

    OK, it looks like your FC level is 5, your pH is 6.8 (very low!), your CYA is now 100--very high.
    An 12,000 gal AG pool with a 2hp pump? I hope you have a 300# sand filter because it's 'way, 'WAY too big for your pool!

    I'm guessing you've been using Tri-chlor tabs and/or Di-Chlor powder because your CYA is very, very high and your pH is low. Both of those types of chlorine add CYA and are super-acidic, driving down pH, especially the tabs. Stop using them.

    First: Put a box of 20 Mule Team Borax in your pool TODAY--vinyl pools with pH below 6.9 can be damaged by the acidity.
    Next: You have a choice: You can drain 6,000 to 9000 gallons and refill, and lower your CYA to a more manageable 30 to 50ppm. I'd go for 6000, and maintain CYA at 50.
    Next: You need a better test kit. We recommend the Taylor K-2006 or 2006C that allows testing of very high chlorine levels.
    Next: Check out the Best Guess table for the ratios of CYA levels to chlorine levels. Start with that here: http://poolsolutions.com/gd/best-gue...ine-chart.html
    Next: Get us more details on your pump and filter. Brand and model will help and, if you know it, the size of the sand filter, either in pounds of sand used or inches.
    Plus a full spectrum of tests of your water:
    FC, CC and TC for chlorine
    pH
    Total Alkalkinty
    CYA
    Calcium levels,

    Just so we know.

    Carl
    Carl

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    Default Re: Just getting started and have a chlorine demand problem

    OOPS. Just noticed your CYA reading used to be 70, but is now 100 which means it could actually be higher than that. So, as Carl said, you might consider doing a partial drain and refill. If you choose not to do that, you'll have to shock to 25 instead of 20 and then when it is all cleared up, your maintenance level is going to be between 8-15 instead of 5-10. Let us know which is your preference and then we'll help you go from there.

  5. #5
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    Default Re: Just getting started and have a chlorine demand problem

    Ran to Home Depot and got a better test kit. Cya on June 3 was - 100. After adding borax this morning to raise PH...as of 3:15 this afternoon the ph is staying at 7.2. Alk test is 170. When you say to raise to 20 and 1 quart of bleach will 1.ppm???? Sorry, all this is very elementary to me. So do I need to lower it by adding shock (bleach) and then wait 30 minutes and work on the ALKto lower to 120. Do have muratic acid. Do I lower it with it? If so how much? In the past week......when we first uncovered the pool we had to add almost 3 gallons of muractic acid (7 cups perday for 5 days)( per chem read out) Dumped $250 in one week then was told to draint he pool.....then I found your help. Is it safe to get in the pool. since i will not have chol tabs in the filter basket, do I just add beach ever so often. How do I maintain if out of town fora few days? Please excuse my ignorance. Hopefully all of this will click and it will get easier....Thank you for yor time. bjoy1956

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    Default Re: Just getting started and have a chlorine demand problem

    You have to get past the high chlorine demand part of this pool's opening. Test your chlorine level as many times a day as you can (minimum is 2, more times per day is even better). Each time you test and find out what your chlorine level is, you'll need to add enough bleach to take the chlorine level back up to 25ppm. Each quart of 6% bleach will add 1.2ppm of chlorine, so use that to figure out how much to add to get back to 25 each time you test. Run your pump 24/7. When you get to the point where you test at sundown and then again in the morning within 2 hours of sunrise and find that your chlorine level hasn't dropped by more than ppm overnight, then you should be in good shape. At that point, you should probably go ahead and keep the chlorine level at 25 for one more day for added insurance and then you can start keeping it between 8-15 after that.

    PH at 7.2 is fine, but if it drops lower than 7.0, you'll need to add some Borax to get it back up above 7.0. Don't worry about alk right now. We'll help you tweak that after you get past needed such high chlorine numbers.

    Hopefully you won't have be out of town while you are having to test and add bleach so often. Once you get past the high chlorine demand time period (which will hopefully on be for a few days) then we can talk about maintenance while out of town.

    Hope this helps.

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