Low pressure on the pump

[duraleigh]

With a normal pressure of 9psi, I doubt that the pump is forcing any sand thru the filter. Something else is going on with that.

Now, are you getting air in the pump basket when the pressure drops to 2psi or does the basket remain filled with water (completely)?

[The Raddish]

Honestly, I don't remember, but I think that there was some air in the pump basket. I can't say with 100% confidence for sure if there was or not.

The reason that I say I think my pump is too strong for my filter is because the S220T Filter is rated at 52 GPM, while the 1hp pump is closer to 60-70 GPM. Even though the pressure is only 9lbs., the flow is higher through the filter than it is designed to take, if I am reading these numbers correctly anyway.

After talking to my wife about all this, we have decided that regardless of the problem with the low pressure, we are going to replace the pump. One other thing that I haven't mentioned is that it has a slow leak that I can't seem to correct. The leak is around where the pump motor goes into the wet end of the pump. It's not much water, but it keeps the fiberglass pad the pump sits on wet.

Are there any opinions on the pumps I have listed in the OP?

[matt4x4]

I would replace the pump seals before dropping 200 bucks+ on a new one unless there are other things that you know for sure are wrong.
I'm wondering if your inpeller stops spinning (slipping on shaft) when you put the vac to it and the resistence increases....
As for the sand - how long have you had your new filter running, supposedly, they do tend to push sand out until it all compacts nicely, I'd just vac it back in for a while see if it stops. Oops - forgot, you can't vacuum

[The Raddish]

The new filter has only been running for about three weeks.

It's alright. I've bought the Pentair Dynamo 2-speed mentioned in my OP. With as much else as has been wrong with this pool, I don't mind spending the money to do it right. Besides, it will pay for itself since it is only a 2.6 Amp draw on low speed, where it will spend most of its time. Even the high speed setting is only 8.6 Amps. Compared to my current 1hp pump which draws 12 Amps, it'll pay for itself by the end of the season anyway.

With this purchase, the only parts of this pool that came with the house are the metal wall and drain. Everything else has now been replaced.

Basically, I have a new pool.

[jenpen400]

I think you will be very happy with this pump. Don't forget the O-ring lube for the lid over the strainer basket.