Reduced water flow after opening pool - etc

[Jeff Lebowski]

Ok Gents, here's your stumped FNG question for the day.

Background-

8-10,000 Gal, inground SWG pool in Virginia Beach. Hayward 4800 filter. New pump motor last summer. Passive solar heat on the roof of the house.

Just popped the cover and vacuumed the majority of crud. Brushed the vinyl sides. Fired up the filter, added 7 scoops of DE in the skimmer. To the pool I added a small jar of shock, 3 gallons of bleach and a half a gallon of Muriatic Acid.

Everything started clearing up and looking much better within an hour. But, then the flow just about quit. Cleared out the skimmer basket and the basket at the filter. Both contained an expected amount of pine needles and junk but nothing outrageous. A fair amount of foam present, but not crazy.

Here's my dilemma -

After about 30 mins the flow though the filter goes to ****. I did a quick backwash thinking I had trapped crud or air and got things flowing nicely again. Went to Homies Despot and upon return was greeted with the same old ****. What can cause this situation?? Initially I have good flow from the pool outputs and good suction at the skimmer. An hour later, it doesn't suck and it doesn't blow.

Can anyone toss this moron a bone?

 

[Richard320]

Your pool is green. Your DE filter is efficient. Add 'em together, you get a clogged filter in a big hurry.

 

[Jeff Lebowski]

Many thanks for the response Richard. That makes sense, but my level of understanding is so laughable that I am unclear on my next step.

I just went out and..

Turned off pump.
Moved multi port selector to backwash.
Turned on pump and ran for about 30 sec (is water supposed to flow out of the waste nozzle during backwash?).
Shut off the pump.
Put selector back to "filter" and
Turned on pump.

Things are flowing nicely now. Do I continue to repeat this step? Sorry for my intransigent ignorance, this is only my second season and my processor is very very small. Last year, things just fired up and ran and I was sucking on a Cohiba and a Martini that night. The pool was equally nasty so the difference confuses me a bit.

 

[elwood58]

Yep. Filter is doing its job, which is catching several seasons worth of crud out of your water. Make sure you are not overloading on the DE, and be prepared to backwash every few hours until it clears.

 

[jblizzle]

You can run the filter in recirculate mode for a little while at the start of the ShockLevelAndMAINTAIN Process (are you doing this correctly?). And they run on filter when you are able to babysit and watch the pressure rise (we recommend backwashing when the pressure rises 20-25% over the clean pressure).

When I backwash, I run on backwash until the site glass is clear. Then on rinse for a few minutes, then back to backwash ... I do this 3-5 times until the backwas is pretty clear. Here is a good tutorial on backwashing :http://www.troublefreepool.com/threads/3853-Use-and-care-for-DE-filters

When was the last time you took the filter apart? See: DE Filter Cleaning Tutorial

Please add your location (City, State or City, Country) to your profile and pool details to your signature as described HERE as it will help us help you.

 

[Jeff Lebowski]

Thanks again, I have amended my signature.

I took the filter apart at the end of last season. I cleaned all of the old DE and crud off and reassembled the filter. I will read your backwashing thread and get busy.

 

[jblizzle]

OK good. At least the filter is hopefully not too clogged up.

You have been adding DE after every backwash right? And not the full amount?

 

[Jeff Lebowski]

No. Just read the backwash tutorial. I surmise now that my backwash was probably far too short, and that I did not perform the rinse step. My thoughts were that I had a plumbing issue and not a filtration issue. "Dumber than a box of rocks" is what my father used to say.

OK. Running out of light and Bourbon. Will do some reading here tonight and re-attack the filter issue tomorrow with more DE and a more enlightened frame of reference. You guys and this site are the bomb. Drinks are on me.

 

[jblizzle]

 

[Jeff Lebowski]

I backwashed it again this morning. I let it blow till the site glass was mostly clear. I then switched back to FILTER and added 4 cans DE. The level of pressure is noticeably higher at the main outlet and the four "gasper" type vents.

Curiously, the pressure gauge only registered about a two needle width increase. I would have assumed that it would indicate a larger differential, but perhaps this is just a gremlin with my pump.

As this is only my second season with the pool I was having a tough time grasping what I was looking at (the low flow situation) because I was comparing it to last year when I had zero issue after the initial addition of DE. I ran the pool all season and never even backwashed it once. The flow stayed strong, the pool clean and the gauge barely moved. Now I know better. I'll also dig into the meat of the site and try and raise my level of knowledge of the pools mechanics and chemistry.

I am a bit confused about the re-addition of DE after backwashing. It sounds a bit like black magic as some peeps suggest "about 80 percent of initial charge" while others caution against adding too little. Is there a tell which confirms correct recharge?

Does DE in the water (both in suspension and lying on the bottom) suggest over charging or is it normal at initial charge? It seems to me that the mesh of the filters "lungs" isn't tight enough to hold it all in and that "some" visible DE in the pool is normal for the first day or two.

Thanks again Gents.