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Thread: Set-up/Balancing Question(s)

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    Smile Set-up/Balancing Question(s)

    I'm in the process of trying to stabilize/balance the water in our new pool. I've dealt with the first round of metal precipitants from my initial FC generation (SWG system), but in the process let the FC go to zero (I didn't take the time to consider just how fast it would drop as I haven't gotten any CYA into the system yet).

    I'm receiving my TF-100 test kit tomorrow, so I'm working off test strips for now. Yesterday after having the pool covered and SWG on boost for about 20 to 22 hours, I had a FC somewhere around 15 to 20 (I guess, darkest color on test strip). Today, with the cover off, in full sun for perhaps 7 hours), zero.

    It's been a long time since I was in a chemistry class, but I've figured out the half-life of the chlorine must be around an hour (or less) in full sun (82F today maximum). Tonight I started up the SWG after vacuuming the iron precipitants out. After about 1.5 hours there was about 1 ppm FC. I added 30 ounces of 8.25% bleach to get what I assume, if I used the pool math calculator (and Richard Falk's pool chemistry spreadsheet) correctly, would be around a FC of 5 tomorrow morning (assuming no organics eating it, which I doubt at this point). But tomorrow will be sunny, so if I use 1 hour as the half-life, I will be back to basically 0.15 FC in 5 hours of full sun. The pool is getting around 8 hour of full sun right now. I understand the half-life is dependent upon a bunch of things, but if I assume only UV radiation is breaking it down, is a half-life of one hour correct? I started to read this (http://standards.nsf.org/apps/group_...lorine-CYA.pdf) and decided I'm looking for the cliff notes!

    So my questions are this:

    - What level of FC should I be maintaining when and after I add the CYA tomorrow evening (shooting for 70 to 80) as I wait for the CYA to full dissolve? Should I drive it up to 15 to 20 every night until the CYA kicks in? Should I drive it to 5 or 6 then cover it?

    Tomorrow evening, I'll be putting in around 3 lbs of solid CYA, if I used the pool math tool correctly. Questions on this are:

    - How long will it take for the CYA to fully dissolve and take affect? Does it take a week, a few hours, or? I understand it may take up to a week for it to show up in the water test.
    - But, does it start working right away?
    - The directions on the CYA say to mix it in hot water and slowly add it the suction side (i.e., the strainer). I have seen in the threads I've read to try to educate myself that people put the CYA in a sock or socks, either tied to the pool wall, or in the strainer (my strainer is currently filled with white paper towels as I anticipate more iron precipitation). Does it matter which method I use? I would think pre-dissolved stuff would ramp up to speed faster, but don't know if matters if it does or not.

    I believe the overarching idea here is to get the CYA in there, get it into the correct range for my SWG (70 to 80) and then bring the FC down (assuming I can keep the level high to begin with) to the correct level, and then run my SWC system the number hours daily need to maintain the target FC of 5 per the TFP guidance for CYA in that range, which brings up one last question:

    The manual for my Intex SWG system states I should be running the SWG system about 4 hours (really 3.5 but the system only work in hour increments) to maintain the FC level. My question is on this is: Is the run time of the SWG independent of the amount of CYA in the pool? I understand that the FC level required for sanitization is a function of the CYA level (higher CYA, higher FC), but do I need to run the system more to get a given FC for a higher given CYA? I believe the answer is "no," but am double-checking everything.

    Thanks again - I wish I could be more helpful. I'm feeling more than bit inadequate. If anyone needs help with questions on mid-year corvette or 1st generation Camaro restoration, submarine weapon systems, or mechanical engineering, I may be able to feel like a worthwhile contributor!
    Intex Ultra Frame 16 x 48 (5000 gal) - Fresh Fill on 7/13/15
    Intex Model ECO 20110 Sand Filter/SWG (2150 gph)
    Intex Deluxe Surface Skimmer
    TF-100 Test Kit, Taylor K-1766 Cloride Drop Test, LaMotte Borate Test Strips, Speed Stir

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    Re: Set-up/Balancing Question(s)

    What does your water look like? Don't mean to be brief but that's the starting point for FC advice?

    CYA is not at all soluble. Putting it in a sock and putting the sock in the skimmer basket (or dangling in front of a return is the best method.

    For all your calculations and dosages, you can assume the CYA is in there just as soon as you submerse it. Squeezing the sock frequently helps. You should have your CYA dissolved and registering on the test in just a few days.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Set-up/Balancing Question(s)

    Welcome to the forum.

    IMO your over-thinking it. With a CYA of ~40ppm I put between 3-4ppm chlorine in my pool daily, pool's in about 70% sun from sunup to noon or so, then slowing falling into complete shadow around 4:00pm or so. I check when I get home from work (4-4:30-ish), & add after dinner.

    CYA in a nylon stocking hung from the ladder for me, squeeze 1-2 times daily and it's complete gone in 3-4 days. I tried the "dissolve in hot water" routine a couple of times & not only is the sock/nylon approach easier, I think it's faster too LOL.

    If you have indeed let your FC drop to 0, or below your minimum for your CYA multiple times you may have an algae bloom starting. Organics will eat chlorine quickly, sometimes faster than UV.

    If it was me, as soon as I got my test kit I would make sure pH is good, then get my pool up to shock level for my CYA and do an OCLT.

    Once you have your proper test kit we will have a better understanding of your situation. Right now your best bet is to guarantee you do not let your FC drop low any more.

    Dom
    Dom - TFP Guide
    Intex 18' X 48" Ultra Frame AGP 6700 gallons | Two Intex CS8110 SWG's | Hayward Pro Series 21" Sandfilter | Hayward 1.5HP Power Flo Matrix pump | Hayward Thru-wall Skimmer | Wanda the Whale | 72 sq ft of Sungrabber Solar Panels with Hayward GLC-2P-A | Taylor K2006 Test Kit, Sample Sizer & Speed Stir | Click Here To Become a TFP Supporter!

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    Re: Set-up/Balancing Question(s)

    Responding to just one point, pre-dissolved does sound good for CYA. However, from everything I've read, it simply doesn't dissolve in a manageable amount of water (e.g. 5 gallon bucket), even if the water is at boiling point - I seem to remember a thread where someone actually tried that as an experiment.

    Now why it would suggest that pre-dissolving works, right in the instructions on the CYA container, is another question.
    18' x 48" ring top pool (Summer Escapes); 5500 gallons; set up June - October, stored during winter; Intex 2500 gph pump (B size cartridge filter) Hayward 21" sand filter + 1.5 hp single speed Powerflo Matrix pump (upgrade October 2016) *** K-2006 test kit, refills from tftestkits

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    Re: Set-up/Balancing Question(s)

    Duraleigh,

    The water is very clear. I vacuumed yesterday evening and this am there are only a small amount of what appear to be metal precipitates.
    Intex Ultra Frame 16 x 48 (5000 gal) - Fresh Fill on 7/13/15
    Intex Model ECO 20110 Sand Filter/SWG (2150 gph)
    Intex Deluxe Surface Skimmer
    TF-100 Test Kit, Taylor K-1766 Cloride Drop Test, LaMotte Borate Test Strips, Speed Stir

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    Scituate, RI
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    Re: Set-up/Balancing Question(s)

    Domct203,

    I'm an engineer and anal-retentive, so I overthink everything! But, I'm trying to digest all the inter-relationships amongst the chemicals, environments, contaminents, etc. I brought the FC to 5 or so overnight and added another round of bleach to bring it up to 12 or so (below shock value, so i'll have to go higher this PM). CYA going in knee-highs (I have a box of them from when I had to some filled with icemelt in them onto my roof this past winter to take out some ice dams).

    I think I'm algae free at this point. I only let the FC drop that one time and the water only went in this past Monday. Water clarity is very good and pH is about 7.5 (test strip).

    Wife just called and said the TF-100 showed up a few minutes ago, so I'll be getting better #'s tonight.
    Intex Ultra Frame 16 x 48 (5000 gal) - Fresh Fill on 7/13/15
    Intex Model ECO 20110 Sand Filter/SWG (2150 gph)
    Intex Deluxe Surface Skimmer
    TF-100 Test Kit, Taylor K-1766 Cloride Drop Test, LaMotte Borate Test Strips, Speed Stir

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