Sand filter pressure

[dannyboy]

After running the pump and sand filter for several days the pressure
will rise from 10 to 20 psi.
The question is when I shut the pump off lets say 18 psi and restart the
pump the next day the pressure may start at 12 psi. It will then take several
hours or days to get back to 18 psi. The psi values vary but the up then
down cylce is continuious. Is this normal?
New Triton II TR100 filter new sand
2 inch pipe
2 HP wisperflow pump
Consistant after back wash pressure 10/11 psi
35k inground.

[Poconos]

Never saw a noticeable change when I was running just sand. Since adding a little DE I now see the pressure creep up a few PSI during the day. Shutting down overnight and restarting next day, pressure cycle sort of starts all over. My guess, and this is only a guess, is fine stuff (DE + fine crud in my case) gets packed on the sand surface and causes the pressure to slowly rise. Shutting off flow causes this stuff to go back into suspension and then takes time to settle on the sand surface again. Just an observation and I don't worry about it.
Al

[graciec]

I am noticing the similar thing.We have a jacuzzi sand filter .I did put 1-2 cups dim.earthtoday and pressure went from about 40-45 lbs,but last year it used to run around 25 before backwashing[no eath last year].
I backwashed today in 2 sessions but it is still not back to where it used to run last year.Why? thanks!

[Poconos]

If we get off the original topic too far I'll split things apart and make a separate thread. Graciec....40-45 seems like a really high pressure for a centrifugal pool pump, which they all are. I suspect your gauge may be way off.
Al

[graciec]

Al,now you've scared me!!!! What should I do? We no longer communicate w/ the place that sold us out stuff 2 years ago.
Is it a matter of resetting the gage?

[graciec]

OK now it's running closer to 50lbs and the gauge needle didn't go back down when I shut it off.Is it supposed to go back down to zero when it's shut off?? can't remember!
I checked the filter basket and it's fine. thanks for any help.

[JohnT]

OK now it's running closer to 50lbs and the gauge needle didn't go back down when I shut it off.Is it supposed to go back down to zero when it's shut off?? can't remember!
I checked the filter basket and it's fine. thanks for any help.

You need a new gauge. It is supposed to zero.

[torsie]

Our gauge broke at the end of the summer '04
and I went to Lowe's to get another one.
The guy said "this isn't the same" but it will work.
It never goes to zero...when it's shut off it goes to 20
and when I turn it on it stays on about 24. If it goes to 30
then I start watching it and usually backwash.
Does anyone think this is a problem as long as I'm aware
of the variations?
TIA

[graciec]

do they go bad that quickly?Even after 2 years? I just tapped on it in off position and it sprang back to 20 or so but it's back up to 40 now. Are gauges available at pool stores? or do I get one from the company that makes our filter?

[JohnT]

do they go bad that quickly?Even after 2 years? I just tapped on it in off position and it sprang back to 20 or so but it's back up to 40 now. Are gauges available at pool stores? or do I get one from the company that makes our filter?

They are available in pool stores, and can fail in weeks. They are junk. I put a new one on this year, and it's already bad. Learn how much your returns ripple the water when the filter is clean, and backwash when that rippling is reduced.

[graciec]

That is an excellent tip! so can I just watch this gauge and know what it marks as normal for now? or is it better to replace? does it need that special tape in the threads that is sometimes used? I will have to see if ours has it now Didn't know they were so junky...thanks

[pj1016]

You can order very decent gauges inexpensively from www.mcmastercarr.com.

HTH,

pj

[matt4x4]

My guage also went after 2 years, just replaced it, tehn took the old guage off, ripped it appart, "reset" it by bending the mechanism inside it until the needle dropped to ) but did not bottom out completely on teh stopper peg.
After this i figured - "yeah right McGyver, I highly doubt this thing will work again". Unscrewed the new (now 15 minutes old) guage, put the old one back in, and voila, EXACTLY the same reading as the new guage gave me seconds earlier.
So, now i have 2 guages that are OK, if one goes, I switch to the other and fix the uncalibrated guage using my new McGyver calibration technique.

[graciec]

cool;i love to take things apart and it would be a good spare.Nothing to lose if it's not 'mcgyverable'......