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Thread: Restricting waste flow rate

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    Restricting waste flow rate

    When I manually vacuum a messy pool when opening it for the year I either find myself wasting a lot of water on waste, or back washing a lot on filter. Next year I plan to restrict the waste flow with 5 ft of 1/2" or 3/4" pipe while vacuuming to waste. Has anyone tried this before or have an opinion?
    17,100 Gal 27' x 52" AGP steel wall vinyl; 44gpm Cooper sand filter; Hayward 1hp sp1580 single-speed; 1.5" plumbing, 1 skimmer/jet, inline chlorinator.
    Chlorine / CYA Chart | SLAM Process | Chlorine cost/fl. oz calculator

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    duraleigh's Avatar
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    Re: Restricting waste flow rate

    Only an opinion.....

    Your flow will decrease just like you want but I'm not sure your vac will be as effective. I would guess the net result would be neutral but it is an interesting idea.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    mas985's Avatar
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    Re: Restricting waste flow rate

    With that small of a pipe, it will clog very easily.

    What about running the backwash hose back to the pool and using a leaf net or some other strainer to capture the "big stuff"? The smaller debris will go back into the pool but that can be filtered out later.
    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

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    Re: Restricting waste flow rate

    To summarize, my problems are: 1) I waste more water than I feel is necessary for adequate vacuuming; 2) I don't like "racing" to vacuum up all the dirt as fast as I can because I'm losing water to waste so fast and I have to battle the hose to keep the head flush with the bottom when I go too fast; 3) I don't like backwashing 10 times in one day on opening.

    I acknowledge my solution doesn't eliminate my problems, but I feel reduces them all. In my opinion, if you're sucking up dirt and not producing dirt clouds when moving the head through the dirt patches, the flow is adequate and any extra flow is wasted.

    Instead of using small pipe, I will use larger pipe on the waste side and put a valve on it to restrict flow. If debris that pass the pump basket clog at the valve, I'll just open it all the way to clear the clog. I think a valve is best anyways because it allows for fine-tuning. Since I have a round pool and I can get a large portion concentrated in the center and the larger stuff always ends up there, I can open the valve more when vacuuming the center and less for the rest of the pool.
    17,100 Gal 27' x 52" AGP steel wall vinyl; 44gpm Cooper sand filter; Hayward 1hp sp1580 single-speed; 1.5" plumbing, 1 skimmer/jet, inline chlorinator.
    Chlorine / CYA Chart | SLAM Process | Chlorine cost/fl. oz calculator

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    mas985's Avatar
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    Re: Restricting waste flow rate

    You will find that when you restrict the water flow, it will significantly affect the vacuum suction because the suction is proportional to the square of the flow rate. 1/2 the flow rate is 1/4th the suction. You can try it if you want, but I really don't think the results are going to be what you want.

    What I would do is use a skimmer sock in the skimmer or leaf basket and put the filter in recirculate. That should allow you to remove most if not all the debris except for the smallest. Then that can be removed with filtering after most of the major debris is remove.
    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

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    Re: Restricting waste flow rate

    The tiny leaf debris were difficult to remove with a leaf net because it was finding it's way through and making the water cloudy. There was enough of it that vacuuming to waste was warranted. I think 1/4th suction power would have worked fine to remove what I was vacuuming, this was much easier to vacuum than the dust that turns to dirt in the pool. I shouldn't have referred to this as "dirt" in my previous post. Recirculating would have caused cloudier water. A couple times when I vacuumed too long, I could lift the vacuum head and debris and cloudy water would come out. When I went to skimmer end, the same was true, and the pump basket was cloudy and wasn't clearing after detaching the hose, and the return jet was barely trickling out with cloudy water. At some point before this near complete loss of flow, the debris were still getting sucked up until the water finally stopped flowing. I would say that's evidence that the debris I was picking up required very little flow to get sucked into the hose.

    Thank you both for your opinions and suggestions, it helped me decide on using an adjustable valve instead of guessing about how much and how small of piping and I will remember the suggestions presented and use them when I feel they are the best option. The sock could have saved me some backwashes, but I think I would still have chosen to vacuum to waste due to the amount of debris if it didn't use so much water.

    Has anyone ever tried using low speed on a 2 speed pump when vacuuming leaf debris to waste to save water?
    17,100 Gal 27' x 52" AGP steel wall vinyl; 44gpm Cooper sand filter; Hayward 1hp sp1580 single-speed; 1.5" plumbing, 1 skimmer/jet, inline chlorinator.
    Chlorine / CYA Chart | SLAM Process | Chlorine cost/fl. oz calculator

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