Pressure just builds......

Opened the pool two weeks ago. 16x32 IG. At first would not even get suction so I replaced the O rings on the Hayward valves coming from the skimmer/main drain and also on the two port valves. This usually is my problem after the winter and that fixed the suction problem.

I have a Hayward DE filter with a multiport and grids. The filter pressure rises after a few hours. I take out the grids, clean them and for about two hours the filter will run at about 15 psi and then slowly work its way up to 24 psi which then releases a low pressure stream from the outlets to the pool. Backwashing doesn't get the same effect as removing the grids but again after two hours I am back at where I started. I only put in a 1/3 of the regular amount of DE to see what was happening but even that stops after two hours. A day later the pump basket is only filling 2/3 of the way. The pool was green when opened (very warm January, lots of rain here in the Northeast) but is now just slightly cloudy (you can almost see the main drain in the 8FT end). Any suggestions? I'm thinking it's either the grids (can they go bad and just get permanently clogged, they are at least 7 years old) or perhaps the multiport gasket.

You must get rid of the algae in your pool. Almost surely your filter is being clogged because of the algae.

Post a set of test results (FC, TC, pH, Alk, CYA) and you'll get lots of good help.

AJ, welcome to the forum. I'm almost positive that Dave is correct in his assesment, algae will clog a de filter very quickly (the reason being that individual algae cells are ~the same size as the filtering channels in the de). However, the grids may have accumulated oils or calcium build up over the course of 7 years, in which case a TSP bath and an acid bath may be in order.
Do you have sufficient water, both in the pool and available to refill the pool, to do your vacuuming to WASTE ?(no relation to me) :) As Dave said, getting rid of the algae should be your priority. If you need any help with the algae removal, take a look at the "Dealing with algae" section of this forum. Good luck and keep us posted - should you need any more help, just ask, some of us live for this stuff ;)

Thanks,

I thought it might be algae as well at first but I'm not so sure now. When I opened I put in 5gal 12.5% brushed the sides, vacumed to waste, then opened the filter, cleaned the grids. Works for two hours. Next day repeated the above minus the 5gal. Works for two hours. Next day another 5 gal vacum to waste, clean the grids (which were not green at all) and then worked for two hours. Daily after that cleaned the grids, let run.

Algae was my first thought as well but it's never taken this long to clear in the past, (first time when we bought it and another when the squirrels ate through the cover). I am on my way to the local pool store to get some fresh chemicals for my testing kit and will post those asap.

I have been around this forum for a while but this really is the first time I have had problems, the help in a friendly manner that everyone gave is really appreciated.

CYA 36
TC 3
FC 3
PH 8.2
TA 109
HARD 140

Realize I have to bring the PH down. I am also going to chemically strip the filter today.

Any other suggestions??

Use a detergent or TSP to get the oils off before acid washing the grids.

Waste...thanks for the advice. It's soaking right now in TSP overnight. In the morning I will rinse well and then do the acid.

Status Update: The water is almost totally clear but the grids still only go about three hours then I backwash and they need another three hours. Then backwash. I did the TSP soak overnight. Then the acid soak overnight. Vacumed to waste. Current test results:

TC 3
FC 3
PH 7.6
TA 109
CYA 36


20k gallon 16x32


Any other suggestions? Maybe time for new grids (they look fine)? The suction and return lines are fine because the pressue is even when on recirculate.

Help!! I'm selling this house in two weeks and don't want to spend too much more money for a pool I'm not going to enjoy.

AJ, what model filter do you have and how much de do you add after backwashing - also what is your backwashing proceedure? (The reason I ask is that there have been a few people recently that have had similar problems due to improper backwashing/ recoating). One last thing, does de come out of the return jets when you recoat the filter?

Waste, thanks for your continued help...

1. It's a Hayward DE-3600. 36 Square foot grids.

2. I turn off the pump. I hook up the backwash hose. I put the multi-port on backwash for at least 3-4 minutes. Typically, I will wait 1-2 minutes after the little jar on the valve is clear. I turn off the pump. Set the pump to rinse for a minute. Turn off the pump. Set the pump to filter. Add 4.5 lbs of DE through the skimmer.

**I haven't been using the whole 4.5 yet as it was stopping flow. I have been using about half of that does before the pressure builds.

I hope this helps you to help me and hopefully solve the mystery. Right now the pool is clear as anything so something good is happening. There was a lot of dirt (debris) on the bottom not that it was clear and I vacumed that out to waste today which cleared it up even more.

3. No DE is coming back into the pool through the return jets.

AJ, here might be the problem, Hayward makes some of the best equiptment out there, unfortunately they don't know how to use it. To backwash your unit correctly:
(Obviously, turn off the pump when changing multiport positions)
Put the multiport on backwash, and watch the sightglass for ~clear.
Rinse the filter till it is ~clear.
Repeat until the 'backwash' cycle is ~clear and rinse again. (~3-5 cycles)
Put it on filter for ~ 1 min. and do another backwash/ rinse cycle.
At this point, you've gotten ~80% of the de out, so only add 80% back in, in your case, it's a little under 4#.
Having way too much, or too little, de in the filter can cause the problem you are experiencing and hurt the unit. Try this a couple of times before you replace the grids.
Good luck in your new home - don't forget to spray-paint 'www.poolsolutions.com' on the livingroom wall, so the new owners know how to take care of the pool:) -Good luck where you are moving! , if it has a pool stay with this site. Again, Good luck!!

Thanks again! I already advised the new owners on the website. I have lurked around here for a long time but never needed to post until now. I'm usually the one giving advice to friends on how to keep their pools clear based upon the info you and others give on the site.

No pool for now at the new house but I'm going to work on my wife on that one.

Thanks!

AJ

Quote:

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Originally Posted by ajwray

**I haven't been using the whole 4.5 yet as it was stopping flow. I have been using about half of that does before the pressure builds.

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Insufficient DE can cause quick clogging of filters. This is because the grids themselves are doing the filtering because they aren't coated.

Thanks John, I just did the backwash thing today that WASTE suggested (2x) and added the 4.5 X 80% lbs of DE. We shall see.

Your help is appreciated.

AJ

AJ, my appologies for my typo last night, I meant to suggest adding ~3.75 lbs of earth to the filter. It seems to me that you have a couple of lbs of de stuck in the filter, that backwashing can't remove. The best way to correct this would be to take apart the filter, and clean the grids with a garden hose. However, as you will be moving soon and have already invested too much time and money into the pool, let the new owners deal with it, but let them know of the possible problem (I was going to suggest a white lie for you to tell them, but doing so would be unethical). Glad that the problem has resolved, though
i can see it comming back until the old de is completely removed and the method I advocated earlier is regularly used. Again, sorry for the typo :(

Waste.....thanks. I re-calculated the DE at 80% like you said and put just under 4 lbs in versus what you wrote. I backwashed like you said and voila, 12 hours (hope no jinx) and it's still staying at the baseline pressure.

Thanks Waste !!!!

I don't have a grid system Hayward filter but I do have a DE filter. Is the backwash method about the same? I have a Hayward EC-50A filter.

Thank you.

Jobeck1, welcome to the forum. Here's a link to my advice on how to clean the 'bump' syle filters http://www.poolforum.com/pf2/showthread.php?p=1671

Quote:

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Originally Posted by waste

AJ, here might be the problem, Hayward makes some of the best equiptment out there, unfortunately they don't know how to use it. To backwash your unit correctly:
(Obviously, turn off the pump when changing multiport positions)
Put the multiport on backwash, and watch the sightglass for ~clear.
Rinse the filter till it is ~clear.
Repeat until the 'backwash' cycle is ~clear and rinse again. (~3-5 cycles)
Put it on filter for ~ 1 min. and do another backwash/ rinse cycle.
At this point, you've gotten ~80% of the de out, so only add 80% back in, in your case, it's a little under 4#.
Having way too much, or too little, de in the filter can cause the problem you are experiencing and hurt the unit. Try this a couple of times before you replace the grids.

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I'm having the same problem (pressure building quickly w/ DE filter) have a few questions.

First, should I bother with the backwash process you describe or just proceed with cleaning the grids now, and use that process in the future?

Second, and more of a newbie question, I have 2 valves I turn when I backwash. The first is a "turn and pull" type valve in front of the filter (is this the multiport?) and the second is an in-line "bypass valve" between the filter and the separation tank. In your instructions, you mention the normal backwash instructions (3-5 cycles until clear), but then you say "put it on filter for 1 min." Does that mean to close both the bypass valve and the multiport valve just as you would when you finish backwashing?

Thanks in advance

Cmcq, first let me say congrats on comming here to keep money grubbing pool guys (like myself ;) ) out of your wallet!
I have very limited experience with your type of valve (it's not a multiport in the sense I was describing, I've always heard of them as 'push/pull' valves), however the process should still work - the idea is to run the water flow backwards through the filter to 'kick the crud off the grids' and out onto the lawn. I can't quite picture your set-up, but yes, before the final 'backwash' turn whichever valves you need to back to 'normal' filtering for ~ a minute.
You might want to consider starting your own thread on this topic as there are probably others here with more experience than I for your type valve and they may be able to give you better advice. However you handle it, know that I'll always make myself available to help you - Waste :)