To backwash or not to backwash -- that is the question!

singerteacher · Jun 9, 2008

Is it true that your filter (I have a sand filter) works better when it's dirty? And that you shouldn't backwash until the pressure gauge reads 10 higher than normal? I've been backwashing whenever the pressure gauge goes 5 higher than normal, but maybe I should wait. (Lots of rain here, so water level isn't a problem.) Also, if I don't backwash at least once when vacuuming, I seem to have worse suction. I always thought that was because the filter was clogged, but maybe there's another reason?

Thanks for your help ...

JohnT · Jun 9, 2008

It can filter finer particles when slightly dirty. If the flow drops, your circulation won't be as good, but it will clean the water it does filter.

giulietta1 · Jun 9, 2008

singerteacher said:
Is it true that your filter (I have a sand filter) works better when it's dirty? And that you shouldn't backwash until the pressure gauge reads 10 higher than normal? I've been backwashing whenever the pressure gauge goes 5 higher than normal, but maybe I should wait. (Lots of rain here, so water level isn't a problem.) Also, if I don't backwash at least once when vacuuming, I seem to have worse suction. I always thought that was because the filter was clogged, but maybe there's another reason?

Thanks for your help ...

A slightly dirty filter works better than a perfectly clean one. The 10 psi rule for backwashing is a rule of thumb. For your pool, it might be 5, 8, or 12. Experiment a bit; try going to a 10-psi increase before backwashing and see how your water looks. Note the pressure at the returns. Just after backwashing, your pressure at the returns should be good. When the flow from the returns becomes weak, that is a sign that your filter needs cleaning.

You might want to try vacuuming to waste. . . then what you vacuum won't go thru the filter and you won't have to backwash it. Just a thought.

Hotrod30 · Jun 9, 2008

My clean filter pressure is 7 lbs and I backwash when it hit 25 lbs. I have to backwash usually once when vacuuming to keep the vacuum strong. The first vacuum of the season is always to waste.

singerteacher · Jun 10, 2008

Thank you!

As usual, a bunch of great replies. Thanks! :-D

neckbeardus · Jun 10, 2008

Don't you lose a ton of water when you vaccum to waste? I do'nt see the value in that but I'm just a newbie so I don't know much. I just backwashed my D.E. filter last night and it was amazing how much pressure I was getting at my returns. I didn't realize how bad I needed to backwash.

JasonLion · Jun 10, 2008

Vacuuming to waste is worth it if you are vacuuming up some serious muck that would clog the filter quickly or cause chemical problems.

Hotrod30 · Jun 10, 2008

neckbeardus said:
Don't you lose a ton of water when you vaccum to waste? I do'nt see the value in that but I'm just a newbie so I don't know much. I just backwashed my D.E. filter last night and it was amazing how much pressure I was getting at my returns. I didn't realize how bad I needed to backwash.

After the cover comes off (Link-Loc), the pool is completly full from snow and spring rains. I start the pump and add a large amount of shock to the water in the evening, let the pump run for a couple of hours in recirc and then shut the pump off. Next morning I vacuum to waste; even thou I can't see the bottom; until the water level comes down to about were it should be. Even thou you can't see the bottom, you know where the main dirt piles and junk will lay. Also, I am only using the sand filter.