Hello from Wylie! Newb with filter question.

[lkalred]

First post on ANY forum. Inherited pool with new house. Algae almost gone. Water clear. Forsaking pool store as have already been subjected to sales pressure.
Last complete test done at Leslies. TF100 on the way. Currently have basic chlorine/ph test kit left by previous owner.

FC-6
ph-7.4
CH-300
CYA-50
TA-80

Question is this, have noticed that immediately post backflush pressure will drop to 16 psi, but will rise to 30 psi within 24-48 hrs. This has happened multiple times. New filter grids installed in Feb.
Unable to bleed air from filter manually after cleaning pump basket.
Will residual air pressure prevent filtration through entire grid causing pressure to rise this quickly?
If there was a blockage I would not expect pressure to decrease at all. How can I obtain a flow diagram for filter as well as grid cleaning procedure? Have opened filter housing, grid removal not immediately obvious.
The service rep who replaced the filter grids did not mention any other problems save for the apparently broken air relief valve, or does this particular unit have an automatic air bleed system? thus rendering my theory moot.


The filter is a Hayward micro-clear DE720S w/ 72 sq/ft grids. 2.5 hp AO Smith pump. 24k gal. IG. plaster. chlorine. pool built 1995. fountain. tree over deep end.


Thanks,


Keith

 

[duraleigh]

Algae almost gone

That may be the answer to your pressure rise. Since the psi drops to normal after you clean, the filter seems to still be catching stuff and slowly the psi increases as the filter gets more and more clogged with particles...even though you can't see them.

 

[lkalred]

Thanks duraleigh!
I guess I will just continue to monitor and backflush.
Previous owner left cellulose fiber instead of DE. when grids replaced, DE also replaced. As I backflush, should I use the cellulose or get some DE? How much of either should I use?

 

[duraleigh]

I guess I will just continue to monitor and backflush

When your kit gets in and you get familiar with it, perform the OCLT described in Pool School. If you lose 1ppm or more during the night, you will want to start the shock process.

 

[257WbyMag]

Welcome to TFP fellow N. Texan! great advice thus far.

 

[lkalred]

What is the advisability of using cellulose fiber instead of DE?

 

[257WbyMag]

Haven't heard too much about using cellulose. It seems to me that DE would filter out finer particles than would the cellulose. That's the main benefit of DE.

 

[Richard320]

What is the advisability of using cellulose fiber instead of DE?

I've got no complaints after using it since December 2010. However, my pool was already clear and sparkling when I made the switch. The manufacturers claim it filters to 2 microns as opposed to DE filtering to 4 microns. If true, it will load up even faster than DE in your situation.

As I see it, the big advantage is that it's biodegradable, so I can backwash onto my lawn without it creating a big crusty DE mess.

 

[BoDarville]

What is the advisability of using cellulose fiber instead of DE?

I use the cellulose fiber during the height of the swim season as an aid to my sand filter. It gives me that little extra bit of clarity that is apparent when the pool lights are on. So far, it has worked well for me. I just need to replenish it after each backwash.

The primary reason I tried the cellulose instead of DE is because of the breathing hazards of DE and that cellulose is biodegradable.

In your case, I would focus on getting rid of all the remaining algae and determine if you need to shock. After that, you could consider giving the cellulose a try and see if it works for you.

 

[lkalred]

I figured out what was causing my filter pressure to rise so quickly.
Finally did some research re: cellulose and found out that the DE and the cellulose DO NOT react well to each other and will cause high filter pressures and low flow rates if used together.
So cleaned all DE off grids and put just cellulose in filter, now getting reasonable filter pressure and no rise yet. We'll see if the water also takes on the polished look they talk about