Will Impeller Upgrades or HP upgrades solve this?

[sjpdallas]

Hi all,

I moved into a house that has a 21K gallon pool. It has an old Stainless steel StaRite/Swimquip DE filter and a 1HP pump motor. When the original pump ran, it had excellent water flow through the jets and through BOTH skimmer baskets.

Soon after I moved in, the pump motor failed. It took it in and got a replacement 1HP that was identical to the original motor. The pool folks told me that it had a mis-matched 1.5 HP impeller so I also got a new 1HP matching impeller and seal.

Things work... but not as well.

When I do a full cleaning of the filter, the pump runs at 9 psi and I have excellent water flow through the jets. However, I only get good flow through 1 of the 2 skimmers. The other skimmer has dismal flow.

When the filter pressure reaches 14 to 15 psi, I have almost no water flow through the pool jets (surface of pool appears smooth) and the water quickly fogs up. At this point, I can do a super brief backwash (15 seconds) and I get great flow again and 1 skimmer works. Pressure will drop to around 10 psi.

My understanding is that I need to backwash when the pressure is around 19psi (10 psi over clean level). At 15 psi, I have no water flow.

I would like to be able to go longer between backwashing and I would like for both of my skimmers to work.

Any thoughts on why this occurs? Do I need to get a 1.5 motor and 1.5 impeller? Do I need to get a 1.5 impeller and stick with my 1HP motor?

Thoughts appreciated!

- Steve

[mas985]

My understanding is that I need to backwash when the pressure is around 19psi (10 psi over clean level). At 15 psi, I have no water flow

That is often a recommendation by manufactures but IMHO, it is a very poor recommendation. I would never ever allow a filter to rise that much in pressure before cleaning it. That is extra 23' of head loss and for most pumps, it will significantly reduce flow rates as you seeing. However, this doesn't mean you need a bigger pump. Quite the opposite. A bigger pump will risk damage to the filter when allowing it rise that much in pressure.

So my recommendation is keep your current pump but to clean the filter at a 25% PSI rise. So if your clean filter pressure is 9 PSI, you should cleaning the filter before it reaches 12 PSI.

You are much better off with a smaller pump because the filter works better and it will save you a lot in energy costs.