Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: Tecniques for remove a large, but measured amount of water

  1. Back To Top    #1

    Join Date
    Jun 2008
    Location
    Thornton, PA
    Posts
    76

    Tecniques for remove a large, but measured amount of water

    OK, so I'm resigned to replacing ~12,000 gallons of water in my 28K pool to lower my CH from 600 to a more mid-range number.

    What's the best technique? I could drop a garden hose in, start a siphon, measure how long it takes to fill a 5 gallon bucket and multiply when to stop the siphon. But as the water get's lower, won't the flow rate decrease? Are my accuracy concerns unwarranted?

    I thought about renting a commercial 3" garbage pump -that would certainly be faster, but again, I have concerns about calculating accurately.

    Is there an easy way to do this? Do some of these pumps have a gallon-age meter?

    Any help would be appreciated.

    Thanks!

    Dan
    28K Gal. 802 Sq Ft., Free Form, IG, Gunnite with Midnight Maui Hydrazzo Carlton Pool. Exposed Aggregate Decking. Jandy DE Filter, 1.5 HP Jandy Pump, SWCG. Zodiac 380 pressure-side cleaner. Completed Construction: May 2008.

  2. Back To Top    #2
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,482

    Re: Tecniques for remove a large, but measured amount of water

    This year I replaced about half of my water "in place" so both draining and filling at the same time. I set the suction up to draw only from the main drain in the deep end and at the same time I added water via the opposite skimmer so as to keep the new and old water somewhat separated. I set up the plumbing so that the pump discharges through a garden hose directly into the drain but I also had to set the pump on low speed so the drain rate would not exceed the fill rate. Plus a garden hose has a lot of head loss so low speed was really the only option. This setup drains the pool at about 10 GPM and the fill rate was about the same. I used a 5 gallon bucket to measure both and since the water level remains constant, the flow rates of both should be about the same throughout the process. After 24 hours, I had about 1/2 the pool water replaced. Based upon salt level measurements afterwards, there did not seem to be a lot of mixing going on so it seemed to work ok. However, the more water that is replaced, the harder it will be to keep the new and old water separated.

    You don't seem to have a similar setup but instead you could use a small drain pump found at the local hardware store instead of your main pump. If you can match the drain and fill rates plus get a good estimate of both, you can then calculate about how long it will take to replace the desired amount of water. You just need to make sure you fill and drain from opposite ends of the pool and water is fairly still with not a lot of mixing going on.

    BTW, this technique is a much safer way to replace water and does not put the pool at risk for lifting should there be any ground water.
    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

  3. Back To Top    #3
    another one's Avatar
    Join Date
    Jul 2010
    Location
    Seattle area, WA
    Posts
    49

    Re: Tecniques for remove a large, but measured amount of water

    AT 802 square foot, if you lower the water 1 inch, you remove 500 gallons. Lowering the water 2 feet will remove 12,000 gallons. So, if you pump, you can measure the rate from the pump, or just watch the water level and when you reach the down 2 foot mark, start filling.
    29,000 gallon, 18' x 44' Indoor plaster pool - 8'x'8 spa in corner. Well water, TF-100,
    pool cover, Pentair MasterTemp 400k btu heater, Jandy RS-4, 4 x 105 sq ft cartridge filters,
    Wisperflow WFE-4 1.0 HP pump for pool, WFE-6 1.5 HP pump for spa jets, MagnaSweep.

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,342

    Re: Tecniques for remove a large, but measured amount of water

    I use my vacuum hose to siphon water out our pool. That 1½" hose will drain a lot of water in a hurry. As A.O. said, 2' of water is about what you need to empty. You could even tie the hose end 2' below the surface and it'll act as an automatic shutoff.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  5. Back To Top    #5

    Join Date
    Jun 2008
    Location
    Thornton, PA
    Posts
    76

    Re: Tecniques for remove a large, but measured amount of water

    Perfect. Thanks folks.

    Dan
    28K Gal. 802 Sq Ft., Free Form, IG, Gunnite with Midnight Maui Hydrazzo Carlton Pool. Exposed Aggregate Decking. Jandy DE Filter, 1.5 HP Jandy Pump, SWCG. Zodiac 380 pressure-side cleaner. Completed Construction: May 2008.

  6. Back To Top    #6
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Tecniques for remove a large, but measured amount of water

    600 ppm is too high?

    Hah! There's folks in California and Arizona who would love to have water that soft!
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  7. Back To Top    #7

    Join Date
    Jun 2008
    Location
    Thornton, PA
    Posts
    76

    Re: Tecniques for remove a large, but measured amount of water

    OK, I really appreciated the water level input, it made it easy to just simply drain to a particular depth. Thanks.

    So in the end, I used the vacuum hose, in conjunction with the pool pump. I had to close the skimmer inputs, and use the main drain only, and pump to waste, but it work really well. It only took a few hours, double teaming it like that. I'm in the process of refilling with two hoses, but, as you might imagine, it's going in slower than it came out.

    Again, thanks again for this input.

    Dan
    28K Gal. 802 Sq Ft., Free Form, IG, Gunnite with Midnight Maui Hydrazzo Carlton Pool. Exposed Aggregate Decking. Jandy DE Filter, 1.5 HP Jandy Pump, SWCG. Zodiac 380 pressure-side cleaner. Completed Construction: May 2008.

Posting Permissions

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