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De Only 20 Psi - "high" Pressure Backs Up Pump? And Filtration System?


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I've owned 3 pools and this is the first DE filter and its been a huge pain.

Bought a new liner, new filter grids, new pump, and new seals/gaskets all last year, still can't get the thing to run right.

The first year the filter didn't seem to "work" so I called out a pool place who told me the grids were bad, so I ordered new grids. with the new grids, the pump seemed to get backed up real easily so they told me to buy a new pump, so I bought a new pump. because I was moving in to the house, this first year was moving very slowly, I just bypassed the filter and ran recirc to get me through the summer, and I covered the pool up.

The liner was torn, so the next year I replaced the liner. I run the filter and it goes from 12-20 psi in about 10-15 minutes, and when it hits 20 psi it backs up and stops moving water. Frustrated, I spent an entire year trying to figure out what was wrong. I ended up getting frustrated and I closed the pool off early.

Now into year 3- I searched on here and thought the filter was impregnated, so I pulled the cells out and cleaned them with chemical cleaner. I tore apart the entire filter/pump/etc assembly and checked everything out and cleaned everything. I bought new seals/gaskets for the pump and the valve because the old one seemed bad. I put the filter grids back in, bought a 1 lb DE scoop so I could be sure I'm adding the right amount, added the DE, and it seemed to be running great, right at about 10 psi. I check it 2 hours later- still running great at 15 psi. Never got it to run this well this long, so I decide I should put in stabilizer (0 stabilizer- chlorine burnout was taking approx 12 hours to go from shock - 0). Check it 12 hours later and now its backed up at 20 psi, and no water is flowing through the filter. I thought it may be because of the stabilizer- I know it can raise filter pressure, so I say "oh well I'll add it later", backwash, clean it out, and now I'm back to the same game as before.

Everywhere I read says 20 psi is normal, 30 psi is high... I find I start out at 10psi though so I thought 20 psi was high in my system. so why is it getting backed up at 20 psi?

Whats next? the only thing I can think of now is to fill the pool in with dirt, but I hate to do that because I spent so much money on the liner, pump filter, but the pool does not work so its pretty useless right now.

36 sf DE filter, 1 hp motor, 2 inlets (skimmer and floor), 3 outlets, 27k gallons in ground with liner.

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PH 7.6, Alkalinity approx. 100 , Cyanuric Acid- 0 or darn close to it, chlorine 3 (shocked yesterday). Calcium hardness I dont test for myself, only when I bring samples in, but last week it was high, but "safe" (we have fairly hard water here, and my understanding is while you can raise it its tough to lower it so its not worth testing for regularly). Next time I'll get a number. Water was clear, its getting hazy and green now because I'm not running the filter. I can get it pretty clear by running the pump on recirc with a good dose of chlorine (thats what I was doing before), a skimmer sock, and an in-pool cleaner. I did NOT recycle the water when I replaced the liner.

Its all hayward equipment, 5 selection valve head, hayward pump, and as I said before 36 sf DE filter with new grids, 1 hp motor

Thanks!

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1) You have to get a proper, drop based, DPD-FAS (or is it FAS-DPD?) test kit, something like the Taylor K-2006 series. This is not an option. Spend the money so you KNOW the Free and Combined (or Total) chlorine, alk, pH, calcium hardness, and CYA levels. They are not hard to use and you know it is right because you did it.

2) With a residential, outdoor pool, CYA plays an important role in helping you reduce the amount of chlorine your pool needs to meet its demands for a sanitary body of water without the levels bouncing, which is one of the things I suspect may be happening. Being 0 is not an option. It should be at least 25 ppm but if you have a salt cell, can and should be in the 50 to 80 range, depending on where you live. The FC should be between 5% to 7% of the CYA level for cell based chlorination and 8% to 10% for all others.

3) High but safe doesn't cut it. You need to know what the level is. Stop using Cal-Hypo to raise the chlorine as it will only make things worse. If the pH is too high for the level of calcium in the water, scale formation may be your issue in the filter. I kind of doubt it but it is possible.

4) How do you normally chlorinate your water? Tabs, powder, bleach, or cell? If you use tabs, where to you put them?

5) You said your chlorine was 3 but didn't specify if that was free and available or total. I you used drops that made the sample turn yellow, that is an OTO test and tests Total. You don't know how much is free and how much is combined. Any combined over 0.5 ppm can cause issues and requires shocking (which is a process and NOT a product).

6) If the water temps is 75 degrees F or greater, I would use dichlor powder pre mixed in a bucket (1/4 lb per gallon) to raise the chlorine and CYA level to where needed. Use bleach and CYA granules in a white, cotton tube sock hung in front of a return if the water is below 75 so you don't have dissolving issues, as ALL powdered chlorines do, regardless of the label! The CYA will take a week or so to show fully in a test.

7) Are you using DE or a substitute? How much? A fresh five pound charge of DE does not backwash fully! Frequent backwashing will likely create a cake inside the grids. You may have to remove the grid assembly again. Remove the header, noting where the short panel is near the port of the header that fits over the stand pipe in the filter. Separate the panels and hose them off fully. Soak them in clean, 32 gallon garbage can. with a half a box of cheap, store brand powdered dishwasher detergent, overnight to remove any oils and lotions that got in the panels. Rince and reassemble the panels, saving the short panel for last. All the others are the same. Put the filter together again.. Now you can put a full charge of DE (slurried) in. Future recharges should only be about 4 pounds and slurried (4 gallons of water to 2 ponds of DE stirred up) and poured in the skimmer (drain off)

8) If it does it again, an acid bath may be called for. Similar procedure to the dishwasher detergent version but using a 5 gallons of water to 1 gallon Muraitic acid for about 6 hours. Use baking soda to neutralize the liquid first. When it stops bubbling, test the pH. It should be neutral before dumping. Always wear rubber gloves and safety eye wear! Don't spill pure Muriatic! Add acid to water! Think and practice SAFETY.

Has this pool ever seen Baquacil or Softswim?

Scott

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Oh, and BTW, get some Chlorox for the time the pump is going to be off. A 1.4 gallon jug is close to a 1 pound pouch of powdered. Add 1 jug per 10,000 gallons or any part there of. Example: 17,000 gallon pool = 2 jugs, 22, 000 gallon pool is 3 jugs, Pour it around the pool and stir it up with a scoop net a couple of time during the day.

Scott

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I certainly understand the value of CYA, and while "0" is not an option, I've been told if I can't get the filter to run 15 minutes before blocking up, the CYA is a secondary issue. (Before I drained the pool CYA was around 40 ppm).

I have a better test kit I use for maintaining my parent's pool at their house, and they are only about an hour away, so I'll get over there today to pick it up and get better numbers. I didn't know any of that stuff would effect the functionality of the filter, as I had the water in tip top shape and it didn't seem to help last year.

is it normal for a DE filter such as mine to run at 10 psi and clog up at 20 psi? everywhere I've read says the filters run at 20 psi and backup above 30.... so therefore if 20 psi was normal for a filter, then its a pump or inlet issue as opposed to the filter issue. However, if 20 psi is high then it may be a filter issue. Since I can't run the filter anyway, I can leave it on recirc like I have been for the past 3 years while I re-soak the filter grids. 5 days ago I soaked them in real TSP and then scrubbed them as well. since then I reconnected everything, dropped in 4 1/2 lbs of real DE (what the filter recommends- even though the pool place said to put in 3 because 4 1/2 "may clog it"- everywhere I read said skimping on the DE only leads to impregnation). Since then I've only backwashed twice (once 5 minutes after putting in DE and once 2 days ago before I switched back to "recirc" instead of filtering just to keep the water moving so I can keep it clean and keep proper chemicals. I have a jug of muriatic acid in the garage.

I'll work first at making sure my levels are spot on with a full quality test kit like I used to use. I'll report back, but if you or somene else could confirm the 20 psi situation above, that would be great.

I feel like the pool place I've been working with either isn't knowledgable or is taking advantage of me, so your help is appreciated!

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A tiny bit more info: I do have 1.5" plumbing, and This is actually a brand new pressure gauge, Installed when I had the liner installed, because of the problem I was having the store suggested the pressure gauge was off, but even with the new one it stalls just short of 20 psi (between 18 and 20), right where you suggest is an acceptable running pressure. I also noticed when it starts stalling (right at 18psi before 20 psi) I get air bubbles coming out of the inlets, and the water level in the pump drops down. If I run recirc I also get a lot of air bubbles the entire time. In prep for removing the grids again I put it on recirc and connected my pool cleaner to one of the inlets. Enough air bubbles came through so that my pool cleaner bag got airlocked and it started floating to the surface, which made me think maybe the DE grids are doing the same thing and getting airlocked?

Thinking air may be getting in the system I bought another set of hose clamps and double clamped all the hoses. No change.The only other places are either goign to be the valves or under ground, but oddly I can close off EITHER intake pipe (I have a floor drain and a skimmer) and with either one off it still does it. I do get some minor water leakage on some settings out of the top of the valve, but the main valve gasket was just replaced.... But I'll stop speculating.

redid the chem tests with a better test kit (not strip).

Free chlorine- 1.5 or so

total chlorine isn't much higher, I'd say Combined chlorine is under .5 or so?

PH- 7.5

Alkalinity- 100

Calcium hardness- just under 350 ppm

Stabilizer approx 5-10 ppm

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Called a reputable pool guy out. He says he has no idea what could be causing it and that I should try to buy a new valve/filter. He said it might be the valve, because the valve doesnt specifically say "DE" on it he thinks it may be for a sand filter, and that is the issue- so I could either order a new valve for DE filters and try that, or buy a new sand filter.

Does that sound like the right course of action?

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