Hi;
On topic: Many pool pumps are over-powered; circulating a lower power pump continuously can be more effective than trying to ram water through narrow diameter pipes with a big pump.
Possibly off topic, but:
I had a 40' x 20' in ground pool with a 1 hp pump, sand filter and brominator.
We ran the 1 hp pump 18-24 h/day to keep ahead of greening, and used a heavy chlorine shock at the start and end of the season in addition to the brominator. It was a ~$2000/season habit, including pump electricity
This spring I converted it to a natural vegetation biofilter, with a 1/4 horsepower immersion pump circulating continuously.
Advantages:
-less energy
-no chlorine or bromine
-much quieter
-alot more interesting to look at and be around
-much less work, with no fussing with filters or skimmers or turning the pump on or off
-no guilt over poisoning toads with bromine. I was a hypocrite buying organic vegetables and avoiding lawn treatments, while dumping ~20 kg of bromine compound into the pool every year.
Disadvantages:
It is not a crystal clear pool anymore, more of a swimming pond, but it is still surprisingly clear (I can see the 10' bottom).
It may become a fish pond once my kids are grown.
Cost:
$2700 for a 40' x 65' EPDM 45 mil pond liner (I had to replace the liner anyway)
$800 for 8 tons of pea gravel and 5 tons of river stone cobble for the biofilter (my nearest good source was a 35 min drive away)
$240 for some rubber patio pavers to make a path to the entrance
$80 for two semi-toy solar powered bubblers, that are fun but probably not doing alot.
It was about 5 weekends of work to pump out the old water, remove the old liner, dig out ~50 wheel barrows of dirt for the biofilter, place the underlay (recycled pool tarp), lay the pool liner (with 20 friends help), put in the pea gravel and river stone.
The biofilter is ~240 sq. ft, on two sides of the pool, roughly 30% of the area of the pool. It is 16" deep, filled with pea gravel, with the river cobble on top. The 1/4 hp immersion pump takes water from the bottom of the deep end and puts it into the biofilter. The water drains back over the edge of the pool in several places.
The only stressful part was that the pool is inground with steel walls and shotcrete base, but the vertical walls are supported by hydrostatic pressure. So once I took the water out, I was pushing to get water back in, to avoid a collapse.
So far there are no signs of mosquitoes, the water circulation is sufficient. There is no bad smell. As nutrients reach the pool, the vegetation filter takes them up and grows. The biofilm surface area in the vegetation filter is immense, compared to a sand filter. The entire pool volume passes through the biofilter is just under a day.
Now I am puttering away, trying different plants in the biofilter to see what grows, building floating islands to grow plants, installing pretty rocks etc.
On a strict financial basis, I think the payback will be ~2 years, on the electrical, chemical and servicing costs.
I am not sure I would do this if I had alot of dirty kids jumping in and out all day (like I had when my kids were smaller).
But for the family and friends to go for a dip, it is lovely so far, and I am really enjoying watching an ecosystem establish.
cheers, Doug