I stopped by local pool supplies store and was told that the Filter
grid may have a hole or manifold was broken. I did see or feel loose
plastic piece inside the individule grid. And I could not tell if DE
powder was recirculated back to pool. I thought the return water was
clean!. Since I never experience the PSI inscrese so quickly which
leads me to believe that filter assembly needs repair or replacement.
Bad thing is my backwash valve was stuck and I never had a chance to
use it. It usually takes 4 -6 month for the PSI to increase by 10 and
then I just take out entirel filter, wash and put it back. I'll cleean
it again to see if there are holes or crack any where. Thanks --pck
Pop` 寫�：

wrote:
I have this pool for a few years and never experienced many issues.
Even the Backwash valve kind of stuck and I always take out the entire
filer grids and washed that way without backwashed first. A few weeks
back, I noticed the Algar increase in the pool. After cleaning the
filter as before I added some Shock. had the pump running 8 hrs a day
for a week. I started noticing filter PSI started to increae by 10
already. I took out the filter assembly and noticed a lot of DE powder
not attached to the filter grid, instead piled up at bottome of
housing. I cleaned that and put back the assembly. Initial PSI was at
18(normal).. But PSI increased by 10 in 2 hours of running pump and
the suction power was almost gone! What is the cause? and replacing
filter grids will solve it? I really appreciate it if any one can
share similar experience. my filter is
STR-RITE 84548-2 48 sqft D.E. vertical filter.

Thanks a lot. -pck

From the sound of it, you simply have a LOT of active algae growth
since the pressure drops to normal and then goes up ten right away.
Sometimes, if the algae gets far enough ahead of you while it's growing,
especially in the sun, it can take four or five DE loads to get ahead of
it. Each cycle should be a little longer than the last after a couple
times, and then stretch out quickly as you finally get ahead of it.
Figure two days total to be back to near normal. Run the pump all
day/night while you have this; do not shut it off - that just lets the
algae regroup and grow some more.

The DE laying in the bottom is just a result of the loss of pressure;
there's nothing to make it stick to the fingers; assuming you have all
the parts indisde the filter present and in place, the DE can't lay in
the bottom when it's running. The flow pushes it up around the filters.

Pop`