high presure low water flow

[yourdarkesthour]

i had high presure and low water flow and i did some research and i found out that i should clean my filter. i cleaned the filter and put DE in the skimmer just like the directions siad to do. and everything was working good for about 20 minutes and the presure started to rise again and the water flow decreased through the jets.
i have a purex trinton fns plus filter.
please help thanks

[Pool Helper]

This may be caused by scaling or liming of the fabric on the grids, usually due to deposits of magnesium or calcium or both. To clean the grids soak them in six parts water to one part hydrochloric acid (muriatic acid or liquid acid).

Let the grids soak for at least 4-5 hours, then rinse thoroughly in fresh water before reassembly.

Hope this helps.