Cause of quick filter pressure rise

[MouseMan54]

I've been struggling with a relatively quick pressure rise on my filter. I'm using cellulose instead of DE. When I clean the filter and start everything up my pressuer is 11 or 12. For the past few months, within a couple of weeks my pressure is up to 20 and everything slows down, sweep won't move, etc. Sometimes we get winds and I'll get a good amount of dirt, etc. There are always leaves blowing in. Wind makes that worse. All my test results are good.

What could be 'clogging' the filter? I'm wondering if it's algae growing on the grids/cellulose but my FC levels is holding well and I don't have any CC. I haven't done the OCLT. Any thoughts?

Current test:
FC: 10 (had a high swimmer load recently so had the cell turned up)
CC: 0
PH: 7.5
TA: 70
CH: 630
CYA: 60
Salt: 3600
Temp: 84

Water is clear and otherwise everything is working fine.

 

[mknauss]

Overnight Chlorine Loss Test

Normally, it is algae that clogs up a filter quicker than normal.

 

[MouseMan54]

So, since I suspect algae in the filter, I want to leave the filter running but the SWG off overnight, correct?

 

[mknauss]

The SWCG off. If you can recirculate (by pass filter) that would be best.

The algae in the filter is from the pool. So you are testing the pool water, not the filter.

 

[bgray9]

I was in a similar situation very recently. I had been using cellulose for 1-2 years and had liked not having to deal with DE for various reasons. Turns out the cellulose was the problem. I did the over night test and the SLAM, even though my pool was crystal clear. No change after the SLAM. I cleaned the filter again and switched back to DE and suddenly everything works great. No quick pressure rise, lack of strong flow, etc. I've read on here before that you need to backwash regularly if you use cellulose, as chlorine will start to break it down and it will block flow through the filter elements. I'm convinced this is what I experienced, and that using the cellulose was the issue.

Here is a link to my recent posting and responses:
https://www.troublefreepool.com/threads/167641-Lack-of-Flow-From-Returns

 

[MouseMan54]

I've thought of switching back just to see. The thing is, my house is up for sale so I don't want to change too much right now. Pool looks good.

I'm of the same thinking on the DE. It's just messier, harder to handle, etc. Back-washing for me is also an issue. I don't have an easy discharge area. I have to go around a building and stick a hose in a toilet. I clean my grids in the grass and just hose the cellulose into the grass.

I'll probably try to hold the course until I sell. Maybe if I get my FC down a bit it will help not break down the cellulose. (Provide that theory is true.)

 

[Saturn94]

How is washing off DE in the grass (that’s what I do, no ill effect on the lawn) any different than washing off cellulose in the grass?

 

[MouseMan54]

DE can be hazardous in certain circumstances. Here's one statement:

If breathed in, diatomaceous earth can irritate the nose and nasal passages. If an extremely large amount is inhaled, people may cough and have shortness of breath. On skin, it can cause irritation and dryness. Diatomaceous earth may also irritate the eyes, due to its abrasive nature. Any dust, including silica, can be irritating to the eyes.

From this article
This publication talks about it being regulated by OSHA.

Cellulose is just wood fiber so usually considered less hazardous. Opinions vary, so just make sure you are informed. For me, with kids and pets in the yard, I felt like cellulose was the better option.

 

[Saturn94]

Ah, I see.

 

[bgray9]

How is washing off DE in the grass (that’s what I do, no ill effect on the lawn) any different than washing off cellulose in the grass?

I found in the past with DE that over a few years the DE will build up in the lawn and, particularly with small children playing in the lawn, I don't like DE dust kicking up, given the health concerns with breathing in DE. Cellulose doesn't seem to build up, as it is biodegradable and probably just adds a little organic material to the soil in the lawn. DE doesn't dissipate in the same way.

I'm getting much better circulation now that I've switched back to DE, but due to the buildup concern, at some point down the road I plan to switch to a cartridge filter.

 

[Saturn94]

I found in the past with DE that over a few years the DE will build up in the lawn and, particularly with small children playing in the lawn, I don't like DE dust kicking up, given the health concerns with breathing in DE. Cellulose doesn't seem to build up, as it is biodegradable and probably just adds a little organic material to the soil in the lawn. DE doesn't dissipate in the same way.

I'm getting much better circulation now that I've switched back to DE, but due to the buildup concern, at some point down the road I plan to switch to a cartridge filter.

Understandable.

We haven’t had any issues in the 14 years we’ve had the pool with a DE filter. But then we have a thick lawn (regular rain here), no kids, and no pets kicking up any dirt.