I need to replace my 8 year old pool's pump and Salt Water Chlorinator. The Salt Water Chlorinator is not a big deal although its expensive at +/- 60,000 baht but my question is about the pump: I am thinking of replacing the 2 HP pump for a 3/4 HP pump so I can run the pool for +/- 14 hrs per day (7 AM - 9 PM) which will be the same "turnover" as the existing 2 HP pump which runs for +/- 8 hrs per day. With the smaller pump, the power consumption will be the same or less and the Salt Water Chlorinator will be running for 14 hrs so will be producing more chlorine. I assume the sand (zeolite) filter should work just as well with the smaller pump. The pool is 14 m x 4.5 m x 1.5 m with +/- 80,000 liters capacity.

The other reason I want to run the pump all day is to keep the pool cleaner as we are upcountry with a 2 rai garden and on a windy day (frequent) we get a lot of leaves / dust on the surface if the pump is not running (we have 2 x infinity edges which keep the surface of the pool clean when the pump is running).

Any comments appreciated.

Generally, the basic rule is that however many daily pumping cycles are programmed in your timer, the system should be able to move the entire pool volume in a total of 6 - 8 hours every 24 hours. Normally, a 1.5 HP pum with a 650 filter unit wouldbe quite adequate for your pool. A good solution would be to replace the sand in the filter with a more performant media such as Zellbrite or DiamongKleen that are up to 30 times more efficient than sand and reduce the need backwashing which wastes the salt in the water.

The price you state for a saltwater chlorinator seems highly excessive, there are Australian models on the Thai market that are fully featured automated pool management systems, and are available from honest dealers for a pool that size from about 40,000 baht and carry extremely long guarantees. They won't pack up after only 8 years. Your current mchine may only need attention to the hydrolysis cell - particularly if it is not of the self-cleaning variety.

For more information ,see my other various posts on this forum about salt water chlorinators. The bottom line is, that your budget will decide which way to go.

Unless your pump is far away (30ft+) a 3/4 horsepower pump will be plenty. The longer the distance to and from the pool the harder the pump has to work. The return water should be coming about 60% from your skimmers and 40% from the main drain with a lot of surface debris.

EDIT: Check your filter before doing anything. Most home pools don't have too big of filters but just in case you went for the max, make sure the filter isn't too big for a 3/4 hp pump.

PS: a genuine saltwater chlorinator will not produce 'more' chlorine, it will automatically adjust the voltage in the cell to maintain the chlorine at the required level - no more, no less - however long the pump is running. DiamondKleen is better than Zeolite (independent university research paper).