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Thread: Experiencing rapid chlorine loss ... Normal?

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    Experiencing rapid chlorine loss ... Normal?

    I'm using pucks right now because my CYA is on the low end (and after 1+ months seems to be holding stable) and supplementing with 8.25% (Home Depot) bleach. I know it's not the reccomended method here, but alas. My filter had been running from 10:30am to 7:30pm every day. I get home around 5:30 and that allows me to test the water and add any chlorine and allow it to circulate a bit if need be.

    For the past month the FC has been steady at 4-5ppm every time I checked it and I haven't had to supplement much at all. However, I recently noticed some mustard algae on my mostly shaded walls. We are having a party this weekend so I decided to shock it and get rid of it.

    I brushed the yellow algae off, put in some yellow klear (sodium bromide) as directed, and brought the FC up to 15 (using 12.5% car boy). I turned off my chlorinator while do this as I wanted to get the FC back down to normal before the party. This was at about 8:30pm when the sun was almost gone. I tested the water 3 hours later (filter set to run 24/7) and my FC was 15.

    8:30am the next morning I checked the FC again and it was still 15. By 3:30pm it was down to 3.5. I added a couple cups at 8.25% and turned the chlorinator back on. My filter was now set back to schedule. Next morning I checked it and the FC was down to 2. I turned the filter on and decided to check it in a few hours. At 12:30 it was down to 1.5ppm. I added a whole jug of 8.25% and at 6:30pm it as already back down to 0.75ppm. I added another entire jug.

    It has been hot and sunny all day (upper 80s). My CYA was between 30 and 40 before I shocked it. All other levels (pH CC TA CH) are in normal troublefreepool ranges.

    Im thinking that my chlorine has been burning off to drastically low levels during the day since my filter doesn't come on until 10:30am and that's how I started to get mustard algae. And then it comes back up by the time I test it in the evening.

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    needsajet's Avatar
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    Re: Experiencing rapid chlorine loss ... Normal?

    How much sodium bromide (Yellow Klear) did you put in the pool?

    Was the pool brushed regularly before the algae turned up?

    Please post all your results like this:

    FC 1
    CC ?
    pH ?
    TA ?
    CH ?
    CYA 40
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: Experiencing rapid chlorine loss ... Normal?

    You have a fairly large pool at 30,000 gallons. You may need to let your pump run longer. Also, when was the last time your DE filter was cleaned? Do you have ladders or lights in the pool that are susceptible to acquiring algae? I would keep shock levels up until you get some steady results.
    16,000 gallon Oval Vinyl Liner Pool (new liner 2014)
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    Purex Triton Model cc100 Cartridge Filter, 100 gpm flow rate, Penfair 1HP Pump
    TF-100 Test Kit

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    Re: Experiencing rapid chlorine loss ... Normal?

    No, it had not been brushed regularly. Last time we did a thorough brush was when we opened it. There is a light but no ladders.

    FC 3.5
    CC 0
    pH 7.6
    TA 100
    CH 280
    CYA 35

    edit: Missed some questions: DE filter was disassembled and thoroughly cleaned a few weeks ago. It said to add 4-8oz yellow klear per 10,000 gallons. I added about 16oz.

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    Re: Experiencing rapid chlorine loss ... Normal?

    Brushing is an often overlooked, important step.
    26' X 52" Intex Ultra Frame. Intex Sand Filter
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    Re: Experiencing rapid chlorine loss ... Normal?

    My pool likes a CYA of 45ppm, might want to bump yours up after you get clear of any algae problems. Also make sure your chlorine is fresh.
    Inground 22k gallon gunite 15x31 main pool, 15x7 wading pool/sunning deck, hot tub/with overflow (9' octagon with limestone top) & slide NSWG, Aqua Blue Pebble Sheen
    Filter dual cartridge Sta-rite 450sq/ft, TF-100 Test Kit
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    Re: Experiencing rapid chlorine loss ... Normal?

    Do you have a good test kit yet? If not order a TF-100 from TFTestkits.net. it is the best value and most tests for the money, Pool School - Test Kits Compared

    When you get the test kit then SLAM the pool. Follow all the steps until you pass all three criteria. Then follow this to kill the mustard algae, Pool School - Mustard Algae

    Then it is important to always maintain FC above minimum for your CYAFC/CYA Chart to keep the pool sanitary and prevent algae.
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    Re: Experiencing rapid chlorine loss ... Normal?

    So I'm still wondering-- is the FC loss I experienced normal or explainable?

    Yes I have a Taylor k-2006 test kit. I went to the pool store to have my water tested today since I was driving by it anyway. They have an electronic tester and their system says my pH is 8.4 and my CYA is 80. I can't believe they are anywhere near accurate.

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    Re: Experiencing rapid chlorine loss ... Normal?

    So yea pool store is bogus. Got home and did a test with two different kits from two different areas of the pool. Both had same exact results.

    C 2.8
    CC 0
    pH 7.7
    TA 90
    CH 270
    CYA 35

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    Re: Experiencing rapid chlorine loss ... Normal?

    everything looks good to me... except that your CYA could stand to come up a bit... and so can your FC ... the heat, and sun tends to eat away at FC... the CYA will buffer it for you.
    14600 gal Intex 24' Round 52" deep AG Pool (Heavily Modified)
    200lb sand filter w/2 speed 1.5/0.5hp pump
    Stenner 45MHP10 Liquid Chlorine (well... bleach) Injector. Borates added.
    K-2006 test kit w/Speedstir
    Pool School - PoolMath - HIGHLY Recommended Test Kits

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    Re: Experiencing rapid chlorine loss ... Normal?

    If you get a lot of sun I'd bring the CYA up to 50 ASAP. I run my pool at 50 and have been considering raising it to 60. This contradicts the TFP recommended maximum of 50 but there seem to be extenuating circumstances (i.e. lots of full sun) that justify it.
    20K gallon vinyl inground pool, Hayward Pro Series sand filter, 1 HP pump, Taylor K-2006

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    Re: Experiencing rapid chlorine loss ... Normal?

    If you do bump up to 50, be sure to adjust your FC to 6 accordingly.
    26' X 52" Intex Ultra Frame. Intex Sand Filter
    26' X 52 Intex Ultra Frame Install
    You can lead a horse to (clear) water, but you can't force him to swim in it!

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    Re: Experiencing rapid chlorine loss ... Normal?

    You going to need to SLAM, so think twice about raising your CYA until after that's done.

    The high chlorine loss is abnormal and largely because of the algae bloom. Only a SLAM can eliminate the algae bloom. It's also correct that part of the increased FC extinction is because of the sub-optimum CYA level, but that's not enough to explain the losses you describe.

    You sound like you're doing a great job on the testing and chemistry. Weekly brushing breaks the biofilm that forms over algae and protects it from the chlorine.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: Experiencing rapid chlorine loss ... Normal?

    Also, do not add any more sodium bromide. That is causing part of the problem. I think that you can mostly ignore it but be aware that it can increase normal chlorine loss for a while.

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    needsajet's Avatar
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    Re: Experiencing rapid chlorine loss ... Normal?

    Just a bump to let you know we're here to help if you need it.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: Experiencing rapid chlorine loss ... Normal?

    I actually think I'm good. I let the chlorine level out and increased my run times on my filter to 8am-8pm. Basically from when the sun starts hitting the pool to when it stops. I haven't seen any signs of algae again. I think what was happening before was the chlorine level was getting too low in the morning.

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    needsajet's Avatar
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    Re: Experiencing rapid chlorine loss ... Normal?

    OK, but just so ya know, we still recommend the test kit and SLAM.

    Pucks are your decision and that is respected. Be sure to determine your CYA increase and compensate by raising day to day FC levels per Pool School - Chlorine / CYA Chart

    Bare minimum FC of 3 ppm and target of 5 ppm are the correct numbers for 35 CYA (we round up to 40 and you'll be there soon anyway)

    Twice a week brushing will help as well.

    Enjoy the swimming!!
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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