Is my filter undersized?

[cherylt327]

Bought house with pool last fall and kept pool up for a month. Was miserable trying to clear the water with "help" from 2 different pool stores until I found TTP. Opened this spring and all is great after a few hiccups. One of those hiccups was accidentally pulling the laterals out of the sand trying to get top off to deep clean sand. Ended up replacing sand to put laterals back in place but they all seemed in great shape. When I went to buy sand was looking for the amount and found it only takes 100lbs according the manufacturer. Based on something pool guy said since I bought the sand at the pool store and reading forums and pool school like crazy wanted to make sure my filter and pump are not undersized. It is a 20 in round Pentair Meteor sand filter and on label for 20 in it states 100lbs so that is what we put in.
Most of the labels on the pump are worn off and unreadable.

Here is the info I can gather on the pump.
Pentair Part: 0-193262-20 FR: W48Y Type: SP Form: PHM
HP RPM:3450 HZ: 60 PH: 1 SF: Code: H

I tried to do some searches but the info confused me so wasn't sure what was needed for my pool -- Above ground 18x33x4

I know the equipment is older so wanted to be prepared in buying the right size if or when it fails instead of just replacing it with the same size that is there just because.

 

[woodyp]

I'd say a minimum 250 lb. sand filter for that size pool. As is, you'll just have to backwash it more often mostly.

 

[Bama Rambler]

I agree with Woody, WHEN you have to replace it go with a 250lb sand or a 200sqft cartridge.

Having said that I wouldn't replace it until it needed it.

The numbers on the motor lead me to believe that it's a 1hp Dynamo pump. A pic would help, but you can look at them online and see if they match what you have.