DE filter pressure sits at 25, when it use to sit at 20

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patplh

patplh

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Jul 29, 2009
210
Massachusetts
For the past 2 years, the normal operating pressure of our DE Filter is 20. After opening the pool a few days ago, it stabilized at 20. Since this morning, i've been backwashing every hour or so because the pressure gets to 25. But I just noticed that, even after backwash/rinse/backwash, the pressure is still at 25. The water coming out of waste is almost clear.. and when i start it up again, it goes to 25 still. I checked all the skimmers and the filter basket.. what am i missing? fyi, at this point, there is almost no DE in the filter now that i've been backwashing/rinsing so much just to see if the pressure would go down.
 
Does the gauge go to zero when the pump is off?

If so, you might try cleaning the grids per the manufacturer's instructions. Running without DE can clog the grids requiring cleaning, so you probably need to do so anyway now.
 
What makes you say "there is almost no DE in the filter now"? Have you actually opened up the filter and looked at the grids, because if not, my guess is that it is packed full of DE and requires a thorough breakdown and cleaning (which should be done at least every year).

I actually just opened my filter up this past weekend and was shocked how much DE was still in there after only 2 backwash and recharge cycles. (Although I guess in truth, I did not get to backwash before the pump died, so I am not sure how much that would have removed.)
 
I just opened a few days ago and at that time, i had installed the cartridges, after they had been rinsed clean at closing in September 2011. I've been backwashing/rinsing for the past 2 days and saw the site window go from cloudy white, green to clear.. which i thought meant, it was clearing up the DE. Are you recommending that I open up the filter and check the cartridges for build up from the last 2 days? I added 4 lbs to start, and after each backwash, I add another 2. I've probably backwashed 8 times since i started.
 
Oh ... from your first post i interpreted it to mean you had not opened the filter in 2 years.

Although like John said, if you ran for any time with no or too little DE, then you may have to pull it apart and clean them. Have you even done an acid soak on the grids?
 
Sorry John, I didn't see your post .. yes, the gauge goes to 0 when the filter is off..

jblizzle, i haven't done an acid soak.. the cartridges looked a little brownish, but for the most part, seemed clear of DE. i had been planning to do a soak, but just haven't gotten around to it.. can i do that with dry acid+ water, or does it have to be muriatic acid? can I do the soak in the filter casing? i'm guessing no and that i need to buy a new garbage can to do the soak? plastic garbage can OK?

is there a huge harm in letting it run at 25 and to backwash at 30 for a day or so? i ask because i don't think i'll have time to go out and pick up any acid tonight. i'd hate to lose a day of filtration, but i guess if it's not effective right now, maybe i should just turn it off?

thanks for the responses!
 
There is likely no harm in running at 25psi ... If you did not know that it was 20 previously, we would think 25 was normal :)
Is there still adequate flow returning to the pool? If so, then it is certainly still filtering the water.

The acid soak can clear off any scale that may to clogging up the grid a little. Honestly I have never done it, so I can not help with the procedure.
 
i actually think something is off.. the suction from the skimmers is very low and the returns are definitely returning water, but just not as strong as before. i'm going to open the filter up later tonight .. i bet i'll find a ton of algae sludge.
since i don't feel comfortable running the filter overnight with this pressure issue and a ton of algae, can i set it to recirculate without putting the filter back together?
 

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so, i've actually never personally opened the filter while the pool is open .. :-D
i already released the pressure from the pressure gauge, do I then open the valve cover at the bottom to drain it, or can I just go ahead and open the clamp?
thanks
 
Hmmm ... seems like when I have had the pump off and open the air valve, most of the water drained back to the pool (although I am not sure what route it takes now that I think about it. Probably should open the drain at the bottom first to avoid dumping water all over yourself if it is not below the split :)
 
i only had an hour to work on this while one kid was at school and the other was napping.. so i didn't do the acid wash.. but the filter grates were green and covered in layer of algae sludge.. so i sprayed them off best i could with a hose at "jet" setting and put it back in.. turned it on.. rush to add DE because I was worried i'd get algae cover again.. i added 4 cans of DE and now it's running at 16. not 20.. 16?? cleared all the debris from the baskets.. i guess this is better than 25, right? the returns are returning water at a decent rate, so i'm not going to go nuts about this.. unless someone tells me i should.. :)
on the bright side, it looks like the pool is clearing up.. still green, but now a murky light olive, instead of a black/green. hopeflly having the filter run will pick up some of that dead algae and then i can finally start vacuuming when i can see the bottom.
 
Keep in mind that pressure is related to flow and head loss through the pipes. To illustrate: when I vacuum, flow is reduced because there is a lot of resistance in the hose. So my pressure drops. Likewise, depending on where I set the valves to draw from affects my pressure tremendously. Normal 20 psi will jump to 25 when I'm set on spa only. The pipe run is much shorter from the spa to the filter.

So... be sure you're comparing apples to apples, that the comparison readings are taken with the valves in the same position.

Of course, clogged grids will make the pressure rise no matter what else!
 
thanks john and richard..

it seems to be working, i wasn't able to completely tighten one of the bolts on the DE Filter clamp - there's a very small space in between the springs, but we've been having problems with the nut/bolt and i can't tighten it further ... gotta order another but .. and hope the problem is with the nut and not the bolt..

any chance you guys know whether it's possible to snap the loop off that holds the bolt for the clamp? i feel like when I'm screwing the nut in, that thing is going to snap off. i can see why they discontinued this clamp system ..
 
I am not sure if you have the same clamp as me, but what I do is tighten up the nut until it is snug and the use a rubber mallet to tap the clamp all the way around. Then tighten the nut a little more and tap tap tap. And Repeat. I never feel like I am putting enough torque on the nut to break anything and get the springs tight with no problem.

You have to make sure the clamp is seated all the way around and you can not do that easily by just tightening the nut and not tapping the clamp all the way around.
 
Thanks everyone!!
my pool is almost sparkling clear.. running an overnight test now, but i think i'll be all set tomorrow, woohoo. i do have one last question about what happened with my filter..
so, i probably ran it too long with just a little DE (i had run out and put what i had left into the skimmer and turned the filter back on). then about 1.5 hrs later i picked up more DE and added it to the skimmer.. then about 4 hours later, i posted about the filter pressure issue.
now, i have DE in the pool.. pics are in this post white-particles-in-pool-cleaner-see-last-few-posts-t44966.html I'm pretty sure it's DE because of how its drying up and crumbles to powder when i squeeze it between my fingers..
how exactly does DE get into the pool? the cartridge is pretty solid and i don't see how those granules could get thru and back into the pool. I don't think it's still a problem since the pool is clear, however, my pool cleaner robot is still picking the granules up from the original mishap.
any thoughts on how it happens? i just want to get a better handle of the mechanics of this thing so that i know better next time.
thanks a bunch.
 
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