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Thread: Just a question about FC

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    Just a question about FC

    I am guessing most of you guys do it this way... but say you have CYA of 50, and the target FC is 6. do most of you keep the FC at 10, and let it drop? At least this is what I am doing... though my CYA is way above that... just an example..
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    Re: Just a question about FC

    I work Mon-Fri so water gets most activity on the weekend. In the mornings, long before anyone is awake I test, top off and add smidge more for the day, especially if I know I have little ones coming who may lack pool etiquette, or if I have folks coming who may be bring suits from other people's water. I am anticipating high bather load so I prepare for it. This also covers any drift from the weekend yard-work and or neighboring farm field work.

    Through the week if it is hotter than blazes, as I am gone 10-11 hours a day, I will bump it up a smidge so I don't drift to the skint side of the zone, I am in a wooded area with messy trees and 2 actively farmed fields.

    I don't "go crazy" with it. When I have little ones and we take mandatory re-lotion, potty, hydration break, I will retest while they are waiting on their sunblock to set just to make sure I am in the zone. Little ones with their sunscreen and swim diapers eat it up, my 10 year old daughter, all of her friends and their "products" ~ (yep 10 year olds now are as product crazy as those goofy reality tv women) along with their sunscreen also eat it up & just Average Joe swimmers consume it ~ so on a busy day I try and stay ahead of it.

    Once the pool has emptied for the night and every night of the week as soon as the sun falls off I test, top off and put it to bed. If I follow this procedure I don't have to SLAM through the season but for when I open it for the year. It's a time and money saver for me/us.
    AGP: 27' x 52" : 17,500 gallon
    300 lb. Sand Filter (75 gpm) / 1.5 hp pump
    Full Sun ~ All Day

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    Mod Squad pooldv's Avatar
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    Re: Just a question about FC

    I would only go about 2 ppm above target most times. 10 is fine in advance of a party or all day swim day. But, going to 10 daily will get a little wasteful. FC decays on a percentage basis, not 1 ppm at a time. But, the real key is to chlorinate so that FC will always be at or 1 above minimum the next time you test and add.
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    Re: Just a question about FC

    well.. mine drops a bit during the day as the sun is on it fully from 7am till 6pm. so leaving it only 2 above would be in danger by time I got home... It passes the over night test... just loses a lot during the day... esp if it was windy and lots of leaves get in there.

    At least this is my explanation of why i do it. I did read some one raises theirs to shock level before people swim in it... IE party or such.

    didn't realize the there was a % part to it.... it just drops 3 or 4 a day.... depending.
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    JoyfulNoise's Avatar
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    Re: Just a question about FC

    Quote Originally Posted by Puppiesonacid View Post
    well.. mine drops a bit during the day as the sun is on it fully from 7am till 6pm. so leaving it only 2 above would be in danger by time I got home... It passes the over night test... just loses a lot during the day... esp if it was windy and lots of leaves get in there.

    At least this is my explanation of why i do it. I did read some one raises theirs to shock level before people swim in it... IE party or such.

    didn't realize the there was a % part to it.... it just drops 3 or 4 a day.... depending.
    3-4ppm per day is a bit on the high side of loss rate for a pool but not unusual. Since your losses are low overnight, most of the loss you are seeing everyday is simply UV photolysis of chlorine. If your pool gets lots of sun all day this is to be expected but it can be mitigated by higher CYA levels. You still have to increase your FC to maintain the appropriate level for your CYA but higher CYA levels do improve/mitigate UV losses. So even though you are raising your FC up to a new target level, the daily loss of FC should be lower and therefore save you from having to add as much each day. As long as you are steadfast and diligent in your testing and dosing, there is no reason why you can't raise your CYA a little higher. Folks down here in the southwest and Texas experience high sun and heat all the time and so you'll find many of us that choose to have a higher CYA level to protect the chlorine from UV loss.

    Another way to keep your pool better balanced and lower UV loss is to use a bubble cover. Since you have a rectangular pool, a 20'x40' blue bubble cover (8 mil is fine) runs about $140. The plastics used to make the cover are (or should be) UV resistant so they will absorb a lot of UV light (even the clear covers absorb a significant fraction of UV). This will cut down on chlorine loss significantly. The bubble cover also arrests evaporation of water and outgassing of CO2 which creates better pH stability as well (acid demand from rising pH goes down). The down side is either purchasing or constructing a reel to make the solar cover more manageable and keeping a close eye on water temperature so as to not create a bathtub (I did that once by accident and left my cover on so long that the water heated up to 97F...not a refreshing swim at all).

    Good luck.

    Matt
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Just a question about FC

    my cya is about 100. i know i know bad bad, but being on a well, i would never be able to fill it up... so i keep it over 10... I do seem to have a handle on it... as in i can predict it somewhat where it will be at the end of the day.. just amazed at how it drops. the solar cover is a good idea. I have one... just since it is so big i have issues trying to put it on and off as we swim randomly....
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    Re: Just a question about FC

    You can always cut the cover in half to make it more manageable.
    8,500gal plaster in-ground with attached spa, two floor drains, one skimmer. Chlorine, City Water.
    Pentair WhisperFlo 1hp Pump, MagnaTek Midcentury EPlus motor, Pentair CleanNClear 200SF Cartridge filter, Purex Triton MiniMax 250 Gas Heater, Pentair SunLite, AutoFill.
    Kreepy Krauly Cruiser, TF-100 with SpeedStir. :D

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    Re: Just a question about FC

    I have thought of that.... then i read, it doesn't work cause it is cut in half, LOL. may do it... that i could manage...
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    JoyfulNoise's Avatar
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    Just a question about FC

    Consider this -

    DIY Solar Cover Roller
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Just a question about FC

    Quote Originally Posted by JoyfulNoise View Post
    Consider this -

    DIY Solar Cover Roller
    Can you buy that? I saw roller cover. now i looked at the picts... that is kind of cool.

    Ok. it is a make it yourself thing... hmmm.... may have to do that when i get time in my life again

    seems they don't sell that within 100 miles of here... the pipe that is... any other types of pipe that would work?
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

  11. Back To Top    #11
    JoyfulNoise's Avatar
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    Re: Just a question about FC

    You can buy what inspired it - The Solar Roller. Look it up on Amazon or In The Swim. Kind of pricey in my opinion.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    JoyfulNoise's Avatar
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    Re: Just a question about FC

    Nope, has to be foam core or cellular core ABS pipe. PVC sinks.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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