Become a TFP Supporter Pool Math Forum Rules Pool School
Page 1 of 2 12 LastLast
Results 1 to 20 of 28

Thread: Solar Cover Question

  1. Back To Top    #1

    Join Date
    May 2012
    Location
    Altoona, Pa
    Posts
    109

    Solar Cover Question

    Does pool water get warmer on a sunny day with the solar cover on or off? I always wondered. I know the cover prevents CL burn off during the day and and prevents evaporation and heat loss during the cooler nights, but for simple heat transfer to the water does it reflect heat as well as UV rays?
    Johnny-M
    Altoona, Pa
    35,000 gallon in ground pool. Lazy L shaped
    Vinyl liner.
    300# sand filter
    3 Returns, 2 skimmers, and No bottom drain
    2hp pump

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Solar Cover Question

    With no wind and relatively high humidity, you would get more heat when the pool was in the sun with the cover off.
    The covers generally are more for maintaining heat by reducing heat loss through evaporation/radiation ... solar cover is a really bad name for them.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  3. Back To Top    #3

    Join Date
    May 2012
    Location
    Altoona, Pa
    Posts
    109

    Re: Solar Cover Question

    Thanks for the confirmation! I figured it reflected some heat as well as UV. I just didn't know if anyone did the experiment.
    Johnny-M
    Altoona, Pa
    35,000 gallon in ground pool. Lazy L shaped
    Vinyl liner.
    300# sand filter
    3 Returns, 2 skimmers, and No bottom drain
    2hp pump

  4. Back To Top    #4

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Solar Cover Question

    It depends on the clarity of the cover. If it's a very clear cover, it will let a significant amount of sunlight through, both visible and some infrared and some UV. Such covers do truly aid heating of the pool during the day. For an opaque cover, if it's white or reflective then there will be little heating of the water, but if it's a dark opaque cover then there will be some heat transfer for thin covers such as electric safety covers. For bubble-type covers, there won't be much sunlight absorption and heat transfer unless the top part of the cover is clear and only the bottom part touching the water is black or dark.

    So in order of heating, it is the following:

    Clear bubble-type cover -- passes through the most sunlight, retains heat well
    Clear-on-top, dark-on-bottom, bubble-type cover -- dark bottom heats up from sunlight and passes heat to the water, retains heat well
    Dark opaque thin cover -- dark cover absorbs heat and passes it to the water, but the thin cover doesn't retain as much heat
    White or reflective bubble-type cover -- does not absorb heat but retains heat well
    White or reflective thin cover -- does not absorb heat and the thin cover doesn't retain as much heat

    The main trade-off is that the clear covers also pass through UV so while you get heating from sunlight passing through, you also get breakdown of chlorine.

    With no cover at all, there is substantial absorption of sunlight which heats the pool where a white plaster pool with 4.5 foot average depth absorbs 60% of the sun's light energy and heats the pool at around 0.7F per hour with noontime sun. Competing with this is water evaporation where the same pool would lose about 5F if 1/4" of water evaporated. Evaporation depends not only on the water and air temperature (except for perfectly dry air), but also depends on the humidity and especially on wind at the pool water's surface. See the thread Water Absorption and Heating from Sunlight for more technical details.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  5. Back To Top    #5

    Join Date
    May 2012
    Location
    Altoona, Pa
    Posts
    109

    Re: Solar Cover Question

    Chem Geek I knew you would have a scientific explanation of my question. Which is exactly what I was looking for. Thank you very much. I appreciate the education. I knew there was a trade-off on heating vs CL burn-off, but wanted to make sure. I am just getting everything ready to open the pool tomorrow and wanted to get the water as warm as I could for the kids. I always keep the cover on while not in use to prevent CL loss. so I may compromise a bit this year on both.
    Johnny-M
    Altoona, Pa
    35,000 gallon in ground pool. Lazy L shaped
    Vinyl liner.
    300# sand filter
    3 Returns, 2 skimmers, and No bottom drain
    2hp pump

  6. Back To Top    #6

    Join Date
    May 2014
    Location
    Reynoldsville PA
    Posts
    4

    Re: Solar Cover Question

    THANK YOU ALL SO MUCH .. Great information...

  7. Back To Top    #7

    Join Date
    May 2014
    Location
    Reynoldsville PA
    Posts
    4

    Re: Solar Cover Question

    Do you have any recommendations for a solar cover, or a website recommendation to purchase one.. and how many mils thick??? Thank you so much... WHAT A GREAT PLACE FOR ANSWERS...

  8. Back To Top    #8
    pwrstrk's Avatar
    Join Date
    Aug 2012
    Location
    Elverson Pa.
    Posts
    4,758

    Re: Solar Cover Question

    Here's a good place for covers. Solar Covers
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

  9. Back To Top    #9

    Join Date
    Jul 2013
    Location
    Chandler, AZ
    Posts
    39

    Re: Solar Cover Question

    Hi, I am also looking to buy a solar cover for my pool. I ve read several suggestions to buy the lightest I can find. But, no body mentioned about 5-MIL cover. Is it ok for me to buy 5-MIL? or is it too thin? I know solar covers don't sell them. But, found on ebay vey inexpnsive. But, good reviews for the seller.

    Thanks,
    Murali
    Build in progress (Design phase), In ground, 16K Gallons, Chandler, Arizona

  10. Back To Top    #10

    TFP Guide

    Kiss4aFrog's Avatar
    Join Date
    May 2013
    Location
    Hudson, WI
    Posts
    2,602

    Re: Solar Cover Question

    Why did they suggest buying the lightest ??

    I'm in the market as mine is disintegrating and is in no condition to even go on the pool this year.
    I'm surprised to find out that a clear one would gain the most heat. Being "north" gaining and keeping heat is an important consideration.
    '70s IG Vinyl 32K gal, Lazy L, Hayward SuperPump 1.5hp 120V, S240 Sand Filter W/DE
    Solar Blanket, Well Water, Borax Added, TF-100 tester. ? too cold
    1979, 275gal Conway Emerald Spa P-100-2, ES-2 Spa Pack, bromine floater, indoor
    TF-100, Best test kit - TFTestkits.net
    Please help keep the lights on, become a TFP Supporter!

  11. Back To Top    #11
    Shelley N's Avatar
    Join Date
    May 2007
    Location
    Denver, Colorado
    Posts
    199

    Re: Solar Cover Question

    This year we are using a new, dark blue, 8ml cover (solarcovers.com $53.99 tax, tag and delivery). I would call it clear dark blue. My findings are it is protecting the chlorine in a BIG way. I have almost NO measurable CYA as I just used what was left in the bottle from last year and never got around to getting more. Might not now. Water temp is has been around 80-85 this year, which I'm also going to say may be a tad warmer than other years this early in the season. We haven't used the pool much at all with it being a cooler spring, so the cover hasn't been off much at all which also helps, but I've been through years like this and don't believe I've noticed such a dramatic saving of chlorine with thinner, clear and light blue covers. Just my $.02.
    Shelley
    Denver, CO

  12. Back To Top    #12

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Solar Cover Question

    If you have no CYA in the water, then the active chlorine level may be too strong and will degrade the cover faster and oxidize your swimsuits, skin, and hair faster when you use the pool. CYA is not just for protecting chlorine from sunlight, but also significantly moderates chlorine's strength so that it is not too strong.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  13. Back To Top    #13

    TFP Guide

    Kiss4aFrog's Avatar
    Join Date
    May 2013
    Location
    Hudson, WI
    Posts
    2,602

    Re: Solar Cover Question

    What kind of pool do you have ?? What level of FC are you keeping it at ??
    '70s IG Vinyl 32K gal, Lazy L, Hayward SuperPump 1.5hp 120V, S240 Sand Filter W/DE
    Solar Blanket, Well Water, Borax Added, TF-100 tester. ? too cold
    1979, 275gal Conway Emerald Spa P-100-2, ES-2 Spa Pack, bromine floater, indoor
    TF-100, Best test kit - TFTestkits.net
    Please help keep the lights on, become a TFP Supporter!

  14. Back To Top    #14
    Shelley N's Avatar
    Join Date
    May 2007
    Location
    Denver, Colorado
    Posts
    199

    Re: Solar Cover Question

    Well, we took the cover off over the weekend and it took about two seconds for the CL to burn off! Dramatic. In fact, the sides got slimy in an afternoon!

    I have a 15 x 30 above ground and follow the chart. Chem geek - You are right, my levels may have gotten up to the 3ppmish occasionally with the low CYA. I hope I didn't damage anything.
    Shelley
    Denver, CO

  15. Back To Top    #15

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Solar Cover Question

    So 3 ppm FC with no CYA will be around 50 times higher in active chlorine than the minimum FC for CYA level recommended here. That just means that every day your cover is exposed to this chlorine, it could degrade as much as around 2 months of exposure at a more suitable lower level. In practice, it's not quite this bad since diffusion limits the rate, but it's still noticeably higher. So since covers last 2-3 years, it would take at least 2 weeks of exposure to "ruin" the cover and probably more like 1 month of such exposure. Also realize that chlorine degradation is only part of cover degradation -- UV is also a factor and that part doesn't change.

    So I suggest getting some CYA into your pool as soon as possible. It will also prevent the chlorine from degrading so quickly from the UV in sunlight.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  16. Back To Top    #16
    Shelley N's Avatar
    Join Date
    May 2007
    Location
    Denver, Colorado
    Posts
    199

    Re: Solar Cover Question

    Agreed, chem geek. I'm at around 30 for CYA now, keeping CL at around 4 as evenly as I can and am STILL amazed at the protection this cover seems to be providing. It's 8ml dark blue for me from her on out.
    Shelley
    Denver, CO

  17. Back To Top    #17

    Join Date
    May 2015
    Location
    Louisville, KY
    Posts
    55

    Re: Solar Cover Question

    Quote Originally Posted by chem geek View Post

    So in order of heating, it is the following:

    Clear bubble-type cover -- passes through the most sunlight, retains heat well
    Clear-on-top, dark-on-bottom, bubble-type cover -- dark bottom heats up from sunlight and passes heat to the water, retains heat well
    Dark opaque thin cover -- dark cover absorbs heat and passes it to the water, but the thin cover doesn't retain as much heat
    White or reflective bubble-type cover -- does not absorb heat but retains heat well
    White or reflective thin cover -- does not absorb heat and the thin cover doesn't retain as much heat

    The main trade-off is that the clear covers also pass through UV so while you get heating from sunlight passing through, you also get breakdown of chlorine.
    Quote Originally Posted by pwrstrk View Post
    Here's a good place for covers. Solar Covers
    Just wanted to say thanks for the info, all. Based on this info I bought the 16mil 18x36 crystal clear cover. Can't wait to get it. At night my pool is around 86, and in the morning it has dropped to 82. Hoping the cover will help.
    Pool: 13,500 Gallon, San Juan StarDust Inground Fiberglass, installed May 2015
    Filter: Pentair cartridge filter, Clean and clear plus
    Main pump: Pentair Intelliflow | Booster pump: Pentair 3/4hp
    Pool Cleaner: Polaris 280 | Chlorine generator: AquaCal Autopilot Digital Nano Plus
    Filled pool with city water & using TF-100 test kit

  18. Back To Top    #18

    Join Date
    Sep 2015
    Location
    Rome, NY
    Posts
    360

    Re: Solar Cover Question

    Quote Originally Posted by guytimes View Post
    Just wanted to say thanks for the info, all. Based on this info I bought the 16mil 18x36 crystal clear cover. Can't wait to get it. At night my pool is around 86, and in the morning it has dropped to 82. Hoping the cover will help.
    Did it work?
    Pool installed 8/2015. 30' round Radiant pool. 21,000 gallons. 200# sand. Hayward Vari flow XL valve. 1.5hp Hayward Power-Flo Matrix running 10 hours/day in two periods. TF100 with speed stir. Sun all day, south side of house
    Order test kit TF-100 w/ Speed Stir and then Poolmath Calculator --- RECOMMENDED LEVELS --- POOL SCHOOL --- Algae? --- Chlorine/CYA CHART.

  19. Back To Top    #19

    Join Date
    May 2016
    Location
    Clinton, NJ
    Posts
    1

    Re: Solar Cover Question

    I have an L-shaped pool and covering the smaller part is real hassle, so I've just been covering the long part which is about 75%. Is it worth using the solar cover if it only covers 75% of the surface area, or is it like leaving the windows open with the heat on?

  20. Back To Top    #20
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,478

    Re: Solar Cover Question

    75% is better than 0%. Heat loss (via evaporation) is proportional to the coverage of the pool.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •