Intex pool circulation vs. typical inground ??
I'm trying to figure out better filter size (and, possibly, better pump size) for out donut pool.
One of the parameters that comes into the decision appears to be turnover (i.e. how much time to get the volume of the pool through the pump and filter). On the Summer Escapes pools we own (1000 gallon currently set up; 6000 gallon recently purchased and not yet in use) I notice that the suction and return points are only a few feet away from each other along the pool wall, and am wondering how that plays into adequate pool circulation. On paper, the 600 gph pump we have (from the smaller pool) should turn over a 6000 gallon pool volume in 10 hours. Even if one assumes that the 600 rating is overly optimistic, it still would seem to be adequate to turn over the larger pool twice daily. However, because the suction and return fittings are so close together, it seems likely that the pool would not really be very well stirred, and that the water across the pool from the pump location might not be moving much at all (and, therefore, would not be getting cleaned effectively).
Even with the larger pump that came with the 6000 gallon pool (described as 1500 gph) it seems that this might be a problem.
I'm pretty much ignorant of the 'circulatory system' of a typical inground pool, but I'm guessing that the underground piping is set up so that suction and return points are widely separated -- is that guess accurate?
Maybe the donut pool setup necessitates a higher pump flow rate (higher than seems needed for turnover) just to stir the water semi-adequately?
Re: Intex pool circulation vs. typical inground ??
Turnover is somewhat irrelevant to pump run time. Some pools only need a 1/2 a turn per day while others require multiple turns per day so there is no one size fits all number. You just need to run the pump for as long as necessary to keep the pool clean and chlorinated. Circulation is also important for the distribution of chlorine but that can usually be done in less than 30 minutes so it is usually not a major factor in determining run time.
However, many Intex pool owners have found that the 1500 GPH pump does not deliver enough flow rate (return exit velocity) to provide adequate water movement so the skimmers can work and all parts of the pool get enough chlorinated water. So many have moved to the Intex 2500 GPH pump and found much better performance.
As for your other questions:
Quote:
I'm pretty much ignorant of the 'circulatory system' of a typical inground pool, but I'm guessing that the underground piping is set up so that suction and return points are widely separated -- is that guess accurate?
No, they are usually side by side so only one trench is required back to the equipment. If the return is separated from the suction side by the pool, they are brought together before going back to the equipment. There is no reason to keep them separated.
Quote:
Maybe the donut pool setup necessitates a higher pump flow rate (higher than seems needed for turnover) just to stir the water semi-adequately?
This issue seems to be return exit velocity. The flow rate is so low with the 1500 GPH pump that it doesn't seem to move the water very much. Based upon other Intex pool owner experiences, the 2500 GPH pump/filter should do the trick.
Re: Intex pool circulation vs. typical inground ??
Quote:
Originally Posted by
mas985
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This issue seems to be return exit velocity. The flow rate is so low with the 1500 GPH pump that it doesn't seem to move the water very much. Based upon other Intex pool owner experiences, the 2500 GPH pump/filter should do the trick.
Thank you -- this is very educational!
I wonder if exit velocity can be improved by changing the fitting at the return -- maybe narrowing the stream of water and aiming it to go more directly across the pool. Once we have the larger pool set up, we may try experimenting a bit (we're high on DIY capabilities, not so high on $$ here :) ).
Re: Intex pool circulation vs. typical inground ??
Reducing the size of the return orifice will increase the exit velocity but it will also increase head loss so flow rate is reduced some. But for most pumps, this will still increase the exit velocity. I am not entirely sure about the 1500 GPH pump.
