Pressure buildind quickly

[kent_polk]

I have a jacuzzi filter for about three years (bought it used) and for the first three years it would run at about 15 to 18 psi. When the pressure would build to 22 to 25 I would backwash. This build-up used to take a few weeks at least. Now I backwash at 22, it will drop to about 18 at the lowest but will build back up to 22 to 25 in about two to three days. Is this a problem, is there a solution?
Thanks in advance

 

[diverman57]

if its sand, change sand
if its de, change de
if its cartridge, install new cartridge

 

[duraleigh]

Is this a problem, is there a solution?

Yes and Yes.

I think there is a good possibility you have algae.

Do you know how much FC you are losing daily? Do you know your CYA?

 

[kent_polk]

Sorry yes it is sand, and the chlorine levels hold just fine have a puck feeder on lowest level and water is crystal clear. Even the backwash water seems clear. CYA was about 40ppm last time I checked.

 

[duraleigh]

If the pressure is building, it is because particles are being trapped in the filter. It is unlikely to be dirt because that is fairly visible.

It is very likely to be algae. Algae does not have to be visible.

You still don't say how much FC you are losing daily which will give us a hint.

The best way to tell is to do an overnight FC loss test which you can only do with a precise FAS/DPD test.