Filter/Pump size

[mackeeg]

Bought a new sand filter 16" down from the 18" that cracked after 6 years of use and we have a 1.5hp Hayward Matrix pump also a solar heater connected to our 18 foot AG pool. Should we have bought a bigger sand filter or will we be fine.

The 16" filter GPM is 35 no idea about the GPM on the pump.

A 22" filter is 55 GPM should I get this one instead??

[aylad]

It's usually much better to have an oversized filter than to have an oversized pump.....if your pump is too strong for the filter, you'll end up just blowing the stuff through the filter and back into your pool, along with a lot of extra sand. I have a 29K IG pool and my pump is only 1 hp and that's plenty. With a 1.5 hp pump on an 18 foot pool, I would go with the bigger filter.

Janet

[mas985]

That pump could easily deliver 60 GPM so a 22" is barely large enough but it would probably work ok.

Also, the 18" may of cracked because of the excess stress put on it by the pump. What was the filter pressure before?

[mackeeg]

That pump could easily deliver 60 GPM so a 22" is barely large enough but it would probably work ok.

Also, the 18" may of cracked because of the excess stress put on it by the pump. What was the filter pressure before?

The gauge didn't work so no idea.

The stress is caused by the water trying to go through the sand? Would it be better to leave the solar heater on all the time since it has to go through more pipe? Would that relieve the stress? The bigger the sand filter = less stress?

Thanks

[mas985]

Yes, having the solar engaged would add head loss and reduce flow rates so it would help some. Also, if you plumb a ball valve in the return somewhere, you can have some extra control over the flow rates if you ever need it.

Also, a large pump on a smallish filter will cause stress in many different ways. First, the excess flow rate can cause the sand in the filter to exit out the returns. It can also cause blow by, a condition where the dirt gets pushed all the way through the filter and back out the returns. So the filter effectivenes is greatly reduced when the flow rate specification is exceeded.

Also, a small filter will have more head loss than a large filter so the pressure in the filter will be higher and will tend to stress the body as well as the internal components a bit more although most filters should be able to handle fairly high pressures. Over time though, higher pressure may result in a shorter life span.

[mackeeg]

Well I ended up taking the 16" back and getting the Hayward 21" sand filter. Did I read somewhere that the filter should sit below your waterline? With such a big filter I should only have to run the pump for a few hours to keep 7600 gallons clean

[mackeeg]

Well new filter is in. The pressure is at 20 and with the solar panels on it is 22. Seems like pretty high numbers, I hope they are close to the norm!

[aylad]

Well, how does your water look? Are you having any problems with stuff blowing back into the pool? I know you'll be happy with the bigger filter--I was afraid the other one was too small.

Janet

[mackeeg]

Well, how does your water look? Are you having any problems with stuff blowing back into the pool? I know you'll be happy with the bigger filter--I was afraid the other one was too small.

Janet

water, so far so good Haven't noticed anything so far but will keep an eye open for blow back!

[mickey4paws]

Well new filter is in. The pressure is at 20 and with the solar panels on it is 22. Seems like pretty high numbers, I hope they are close to the norm!

My filter runs at 20, so you should be fine.