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Thread: Another first time FAS-DPD Tester

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    Join Date
    Jun 2013
    Location
    Lazio Italy
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    Another first time FAS-DPD Tester

    I too am a first time FAS-DPD tester. I have been away for 3 weeks. Now back in Italy from the UK.
    Our pool has been looked after by a local man using the simple OTO kit. I don't think he brushed it whilst I was away as the pool walls were slightly green when I arrived.
    I have brushed it twice and hoovered it twice since my return a week ago. Washed the filters daily.
    I have upped the flow to 8 hours daily.
    I now have a LaMotte prof 7 kit. I took the first readings and FC was 6.8 - so assume he might have shocked the pool.
    TRC was 1.56
    CC therefore -5.24
    PH was off the bottom end of the scale. Have added about 25 kilos Of PH + and it now reads about 7.0. Will get some more tomorrow.
    TA 220
    CYA 100!

    Water looks sparkling.

    Air temperature is cooler than normal for this time of year, (18c) but forecast to be much warmer by the end of the week (28c). We have also had much higher than average rainfall.

    I read that I need to lower the TA as I have a vinyl pool. Any suggestions?
    I know we need to reduce the CYA. I have read that oxygenation or aeration is the only alternative to replacing the water. Again, any suggestions?

    All advice would be welcome, to help me balance the water, but please remember I am a novice, so as much as possible, please use the simplest of terms!

    Thanks. Caro
    23k, IG,Vinyl, sock, 5 years.

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    Sebring, Florida
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    Re: Another first time FAS-DPD Tester

    I am a novice, so as much as possible, please use the simplest of terms!
    I would suggest you read "The ABC's of Pool Water Chemistry" up in Pool School. It's the basic stuff and will help you understand some of the misconceptions. Post back with questions after you give that a good read.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Join Date
    Jun 2013
    Location
    Lazio Italy
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    41

    Re: Another first time FAS-DPD Tester

    Thanks for the advice Dave. Having read the ABC section, I realise that because we have such a high CYA content, we will need more FC to achieve clean water. On the FC/CYA chart it appears that with a reading of 100CYA I should keep the free chlorine between 7 and 12ppm. Assuming my PH level is perfect- it is now up to 7.4, so we are getting there - will the water be comfortable to swim in with such a high level of FC?
    Regarding the TA. Our reading is 220. I know with a vinyl pool the levels should be lower, so I have adjusted the return to break the surface and over time I hope the TA will drop. One thing I find puzzling is that our PH level is always low and yet in connection with high TA, the norm apparently, is for PH to drift higher. Why should ours be the opposite?
    Our CYA is 100 and I know that normally the max should be 50, but when in lots of hot sunshine it is apparently OK at 80. We normally have very long hot days. Do I really have to partially drain the pool to correct this?
    Thanks in advance. Caro
    23k, IG,Vinyl, sock, 5 years.

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