Backwashing multiple times a day?

[ICSVortex912]

Hello! First I'd like to send a blanket "thank you" to the pool wizards here. Your seemingly endless wealth of knowledge has gotten me started, and I'm excited to learn more!

Here's the scoop: my wife and I just bought our first house. It was built in 1956 and we are only the second owners, and from what my neighbors tell me the pool had not been opened for a good 7-8 years. It's a monster, in-ground concrete pool - 20' x 40', about 35,000 gallons. To add to the fun, the "cover" that was on the pool had gigantic rips running through its center, so it was not actually preventing debris of all kinds from getting into the pool. Needless to say, we had a serious swamp on our hands (and still do).

I am currently SLAMing the pool following this forum's advice, and things are clearing up slowly but surely. In the last few days, however, the pressure on my filter has been skyrocketing to the point of needing to be backwashed 2-3 times per day. (Normal pressure is around 20, and I am backwashing at 28-30.) Is this normal? If not, what's the next step? It's an old sand filter -- is it possible that the sand needs to be changed? I have no idea when it was last changed, if ever.

Current numbers, if they help, are roughly:

pH - 7.2
CYA - 30
FC - 12 (SLAMing level)
CC - 1

(All measured with a Taylor K-2006 kit)

Thank you in advance for your advice!

Sam

 

[zea3]

Hi, welcome to TFP! The sand is doing its job filtering out all the dead algae and debris. Since you don't know when it was last cleaned you may want to open up the filter and deep clean the sand filter. That will ensure the sand is clean, loose, and not channeled.

 

[Mr Bruce]

Have you removed as much debris as possible first with a leaf rake (looks like a net)?

Doubt the sand needs changing, but it might be worth an hour to do this: Deep Cleaning a Sand Filter

 

[Richard320]

That's pretty normal.

If there's still a lot of fine stuff settling out in the bottom -- and you'll see it get stirred up when you brush -- you could try letting it settle for a couple hours and then vacuum with the multiport on waste. That'll bypass the filter and send all that crud out the waste pipe. You'll lose a lot of water, but probably no more than all the backwashing has cost.

If it's just cloudy, then vacuuming to waste won't help.

And a deep cleaning is probably a good idea.

 

[ICSVortex912]

There is definitely quite a bit of fine stuff still on the bottom of the pool. I can finally see the shallow end of the pool and it is almost entirely clear, but quite a bit of stuff gets churned up when I brush on the deep end, which is still very cloudy.

I've been hesitant to vacuum to waste, simply because I don't want to lose a ton of water, but I may consider it. In the meantime, I will definitely look into doing a deep clean of my sand filter.

Thanks!

 

[Richard320]

There is definitely quite a bit of fine stuff still on the bottom of the pool. I can finally see the shallow end of the pool and it is almost entirely clear, but quite a bit of stuff gets churned up when I brush on the deep end, which is still very cloudy.

I've been hesitant to vacuum to waste, simply because I don't want to lose a ton of water, but I may consider it. In the meantime, I will definitely look into doing a deep clean of my sand filter.

Thanks!

Just a thought... If the debris you see is good-sized, like disintegrating leaves and twigs... could you stretch a knee-high nylon over the end of your vacuum head connection and cram the hose on over it? The nylon would fill up with any debris too big to pass, which should slow down the rate of the filter clogging.

A nylon over the skimmer basket wil do the same, if you can coerce the big stuff to rise to skimmer level.

 

[ICSVortex912]

Just a thought... If the debris you see is good-sized, like disintegrating leaves and twigs... could you stretch a knee-high nylon over the end of your vacuum head connection and cram the hose on over it? The nylon would fill up with any debris too big to pass, which should slow down the rate of the filter clogging.

A nylon over the skimmer basket wil do the same, if you can coerce the big stuff to rise to skimmer level.

That is an excellent idea. I will definitely try that out, as disintegrating leaves seem to be the main issue that's leading to so much backwashing. Thank you!