high filter pressure??

[Topher55]

hi,

just bought a house with a pool. the filter pressure runs at about 22 PSI right after a backwash is this abnormally high?

my equipment is

hayward RS1500 pump with ratings of 1.5HP, 1.33 SF, 2 THP
tagelus 60D sand filter
1.5" plumbing everywhere
1 skimmer
2 returns (i noticed some fresh plaster spots at the same height as the other returns, guessing there use to be more returns)


And for what it is worth I dont feel like it filters that well, I seem to always get a poof of something out of the returns when i start up the pump. I had to drain and fill about 75% to get my CYA down and am currently slamming. i am passing everything but the clear water criteria to stop the slam.... test results below

FC=24.5
CC=0
PH=7.4 (measured before starting SLAM)
TA=180
CYA=60
CH=390

some other factors that may be of importance,

i have been doing the add some DE to your sand filter trick.

I rinsed the sand once by removing the top valve and running the hose down in the sand, water started running clear but not 100% sure I got it perfect, its difficult to get a hose and broom handle down in the top of that filter trying to break up chunks and watch out for the laterals all at the same time.

If I run the polaris and it gets really cloudy (stirs up dust), about 2 days later with polaris out of the pool dust will settle on the bottom. if i try to vacuum to filter the pressure spikes then plumes of dust come out of the returns and the pressure drops back down.

so anyway my thought was the pressure was too high which forced this dust Crud all the way through the filter and back into the pool, my next step was to change out the sand. but am really just playing guess and check at this point so figured i would ask here..


Thanks

 

[jblizzle]

That pressure is not unreasonable ... the 1.5" pipe likely is a contributing factor as it adds head loss.

That 60D is a 3.1 sqft (24" diameter) filter, for a 25k gallon pool, we would recommend at least 4.6 sqft (29") sand filter. So, given the fairly large pump and the smallish sand filter, that could contribute to your filtering ability.

Do you have the ability to vacuum the settled dust to waste instead of into the filter?

Changing the sand is not going to help.

Ideally, I would suggest a large filter and a smaller 2-speed pump ... given the choice of only 1, I would get a smaller 2-speed pump (assuming you do not have a spa or water features that need that much flow rate).

EDIT: an even cheaper option upfront would be to just replace the pump's impeller with a smaller one (~$20). That will lower the flow rate and maybe help the filter and will make the motor cheaper to run (although not nearly saving as much as a smaller pump on low speed would).

 

[Topher55]

Yes I can vacuum to waste, was going to do that sunday morning, want to let it settle as much as possible. but seems like a waste to have to dump so much water because the filter wont pick it up.....

i did find a 4 160 pentair on craigslist for $350 maybe ill grab and install that. no Spa but do have a water feature. also forgot to mention i have a booster pump which T's off to both the polaris and water feature so i dont think pressure will be an issue on a smaller/VS pump.

so it looks like the filter is quite a bit undersized..... the guy selling the pentair pump also has a DE filter maybe i should look into both, he might cut me a deal

so no Sand change thanks for the info really wasnt looking forward to disposing 325 #'s of sand

Thanks again!!

 

[jblizzle]

I would not say the filter is way undersized (like the one on-going thread that has a 90sqft cart filter where we would recommend 470 sqft ), likely it would be fine with a smaller pump.

I do not understand what a "4 160 pentair" is?

 

[Topher55]

Ok, well ill go after the pump first then

the pump i referred to is the pentair intelliflo 4x160
http://www.poolproducts.com/SPP/product ... f_id=E2850

 

[jblizzle]

$350 for the $850 Intelliflo is a great deal ... what is wrong with it

 

[Topher55]

$350 for the $850 Intelliflo is a great deal ... what is wrong with it

as far as i can tell, nothing! guy said he took it out from a house he left, only ran 1 season and was in tip top. I of course havent seen the pump but was still on the fence and would be a 2 hour round trip to get it. given my current issue ill make it a priority to go check it out. he also has a pentair 4000 series filter for $450. might consider getting both

 

[jblizzle]

Likely that DE is only 48 sqft and we would recommend the 72 sqft size for your pool ... or at least the 60sqft.

If it is a 48 sqft ... that would be the equivalent filter capacity as what you already have in the 24" sand filter.

 

[Topher55]

Good to know. Ill work on getting the pump taken care of first then look at a new filter when I have the $$ to drop.

On a brighter note my pool was noticeably clearer when I got home from work today, still not passing SLAM but will in another few days at the current rate. Maybe I just need patience with the undersized filter.

Thanks for all the help.


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[jblizzle]

How are you deciding when to backwash? We recommend doing so when the pressure rises 20-25% over the clean pressure. So about 27psi in your case.

 

[Richard320]

Good to know. Ill work on getting the pump taken care of first then look at a new filter when I have the $$ to drop.

On a brighter note my pool was noticeably clearer when I got home from work today, still not passing SLAM but will in another few days at the current rate. Maybe I just need patience with the undersized filter.

Thanks for all the help.


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Your complaint is not uncommon - sand filters do seem to be slow when clearing a swamp. Have you seen pool-school/add_de_to_a_sand_filter ?

 

[Topher55]

Yep added the DE per instructions in that thread. I found that thread and have been doing the DE trick since it turned green. Can't compare to tell if it is helping but pretty sure it doesn't hurt anything.

Thanks


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[Topher55]

How are you deciding when to backwash? We recommend doing so when the pressure rises 20-25% over the clean pressure. So about 27psi in your case.

Yep I saw that recommended in another thread, I'm back washing right in the 27 psi range. Sometimes I push it a little bit more. Noticing it filters noticeably better when pressure is > 25 psi.


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[DrHorshenschwartz]

Yes I can vacuum to waste, was going to do that sunday morning, want to let it settle as much as possible. but seems like a waste to have to dump so much water because the filter wont pick it up.....

i did find a 4 160 pentair on craigslist for $350 maybe ill grab and install that. no Spa but do have a water feature. also forgot to mention i have a booster pump which T's off to both the polaris and water feature so i dont think pressure will be an issue on a smaller/VS pump.

so it looks like the filter is quite a bit undersized..... the guy selling the pentair pump also has a DE filter maybe i should look into both, he might cut me a deal

so no Sand change thanks for the info really wasnt looking forward to disposing 325 #'s of sand

Thanks again!!

Just checking out your previous threads since you had been commenting on some I had been following.
I saw where you mentioned not looking forward to getting rid of 325# of sand. If you do ever change the sand just remember it's just sand. You could use it for lots of things. Grow some carrots. They love a very sandy soil. I've seen videos of competition growers using 55gal drums of super sandy soil to grow some massive and straight carrots. Odd transition from pool to garden but I have both and I'm always looking for ways to retain soil anything.