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GCAT

Chronic De Filter High R Pressure

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Can the grids go bad on a 4 year old Pentair DE filter? They do not clean up during a normal BW,rinse,BW,rinse,BW,rinse cycle. If I take the filter apart after the BW rinse cycles the grids are still caked with debris. If I remove the grids, hose them off, reinstall them in order and reassemble the filter housing the R pressure comes down to 18psi. I have plenty of pump pressure, the valve appears to be switching fine. The pool stays clean, but again I cannot seem to get the grids clean during BW.

Its a salt water, 40K gallon pool and I have just recently had this problom. Yesterday I was looking at 30psi of R pressure so I BW for 3 mins, rinsed for 90 seconds and repeated 3 times but I never saw any dirty disscharge through the transparent waste water tube. The disscharge flow out of the waste water pipe was great but like I said the waste water was clear as a bell. the R pressure droped to 20PSI but I have yet to add any DE. I usually add about 8 cups of DE after BW.I just checked and I am approaching 30PSI of R pressure again. I bet if I pull the filter apart I will find stopped up grids! Again, pool water stays crystal clear. The mainfolds in the filter look OK. Any ideas

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Can the grids go bad on a 4 year old Pentair DE filter? They do not clean up during a normal BW,rinse,BW,rinse,BW,rinse cycle. If I take the filter apart after the BW rinse cycles the grids are still caked with debris. If I remove the grids, hose them off, reinstall them in order and reassemble the filter housing the R pressure comes down to 18psi. I have plenty of pump pressure, the valve appears to be switching fine. The pool stays clean, but again I cannot seem to get the grids clean during BW.

Its a salt water, 40K gallon pool and I have just recently had this problom. Yesterday I was looking at 30psi of R pressure so I BW for 3 mins, rinsed for 90 seconds and repeated 3 times but I never saw any dirty disscharge through the transparent waste water tube. The disscharge flow out of the waste water pipe was great but like I said the waste water was clear as a bell. the R pressure droped to 20PSI but I have yet to add any DE. I usually add about 8 cups of DE after BW.I just checked and I am approaching 30PSI of R pressure again. I bet if I pull the filter apart I will find stopped up grids! Again, pool water stays crystal clear. The mainfolds in the filter look OK. Any ideas

Check out this thread for a general overview and some tips and tricks pertaining to cleaning/maintaining a DE filter.

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if your not getting any dirty water thru your sight glass, the filter isn't backwashing properly. What kind of pressure are you getting while backwashing? It should be significantly lower than your normal "dirty" pressure. Your grids may be impregnated, and need to be chemically cleaned. This could have happened if you are putting in 8 actual cups (measuring) of D.E. Depending on the size (square foot) of your filter, it may not be enough. Then with the grids blocked, you can't backwash well enough to get the D.E. out, then you put more D.E. in, and thats when you get the caking. Do you think this is what could have happened? I can only guess from here, not seeing your filter first hand.

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if your not getting any dirty water thru your sight glass, the filter isn't backwashing properly. What kind of pressure are you getting while backwashing? It should be significantly lower than your normal "dirty" pressure. Your grids may be impregnated, and need to be chemically cleaned. This could have happened if you are putting in 8 actual cups (measuring) of D.E. Depending on the size (square foot) of your filter, it may not be enough. Then with the grids blocked, you can't backwash well enough to get the D.E. out, then you put more D.E. in, and thats when you get the caking. Do you think this is what could have happened? I can only guess from here, not seeing your filter first hand.

The pressure is much lower during back wash. I think I have impregnated grids, they seem to hold water a little to long when I wash them down with the hose. I bouhgt a complete new Pentair grid set (249.00), should get them in a few days out of Dallas. I will install the new set, fire the system back up,then measure out the exact amount of DE on a SCALE(6LBS as per the tag on the filter housing). Mix the 6LBS of DE in a bucket with pool water and slowly pour into the skimmer. Then buy a

case of CORONA light, drink one beer for every ten minutes the pressure stays where it should (20psi max). If all goes well that will be 24 beers in 4 hours, after that who cares about pool pressure. The article on DE filters was very helpfull, I will let you all know the results. Thanks Frank in Houston

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I posted this under the other topic as well...

Don't clean the grids with acid. After disassembling the filter and grid assy, use a good detergent/degreaser and a stiff plastic bristle brush to clean the dirt and oils off the grids. Acid isn't nice to the fabric and should only be used as a last resort.

Grids aren't normally "ruined" unless they have holes or tears in the fabric. Usually your bag of DE will have a chart for proper amount of DE. DE is measured by volume, not by weight, so a scale won't help. For a 60 square ft. filter, use a one pound coffee can (or equivalent measure) and add 12 cans slowly into the skimmer. If you buy a 25# bag of DE, half a bag is good for a 60 sq. ft. filter. This is a proper coating and you should generally use this amount after every backwash. I know, it's heavily debated about how much to add after backwashing, but you want the proper amount for coating and for depth on the grids. Many people only use half, but this isn't a good practice. DE is cheap, so don't scrimp on something that protects a more valuable item. No manufacturer of DE filters recommends less than a full coating. Since the filter manufacturers don't make/sell DE, there's no reason for them to recommend more than actually needed.

24 sq. ft. = 4.8# DE

36 sq. ft. - 7.2# DE

48 sq. ft. = 9.5# DE

60 sq. ft. = 12# DE

72 sq. ft. = 14# DE

A little over or under won't make a difference, but try to get reasonably close.

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Usually your bag of DE will have a chart for proper amount of DE.DE is measured by volume, not by weight, so a scale won't help.

Thats not true. D.E. is most certainly measured by weight! Otherwise the manufacturer would not tell you to precoat with X Lbs. of D.E.

For a 60 square ft. filter, use a one pound coffee can (or equivalent measure) and add 12 cans slowly into the skimmer.

That is correct, but, You're thinking a one pound coffee can will hold one pound of D.E.? 12 one pound coffee cans of D.E. isn't the same weight as a half of a 25# bag. You can only get about a half pound of D.E. into a one pound coffee can because coffee is denser than D.E.

Grids aren't normally "ruined" unless they have holes or tears in the fabric.

Useing too much D.E. can also ruin grids from caking. The weight of the caking breaks the skeleton that the nylon covers, and when there is nothing to separate the two sides of the nylon jacket,the water pathway gets sealed off and drives the pressure up.

If you buy a 25# bag of DE, half a bag is good for a 60 sq. ft. filter.

I believe that is twice the recommended amount.

This is a proper coating and you should generally use this amount after every backwash. I know, it's heavily debated about how much to add after backwashing, but you want the proper amount for coating and for depth on the grids. Many people only use half, but this isn't a good practice. DE is cheap, so don't scrimp on something that protects a more valuable item. No manufacturer of DE filters recommends less than a full coating.

And none (to my knowledge) recommends twice the amount.

Since the filter manufacturers don't make/sell DE, there's no reason for them to recommend more than actually needed.

24 sq. ft. = 4.8# DE

36 sq. ft. - 7.2# DE

48 sq. ft. = 9.5# DE

60 sq. ft. = 12# DE

72 sq. ft. = 14# DE

A little over or under won't make a difference, but try to get reasonably close.

If you change the # symbol to: "One pound coffee can scoops", i think that info would be accurate.

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UPDATE: PROBLEM SOLVED> The new Penatir filter grids arrived yesterday. I opened the box and it was the entire grid

asbly already bolted together with a new manifold and base. I went home to drop them in. When I arrived the R pressure was 30PSI. I shut the sys down, bleed off the pressure, opened the filter housing and lifted out the old grid asbly. I grabbed the new grid asbly, lubed up the point where the pipe meets the manifold and lowerd the new asbly into the housing. Re-installed the top of the filter housing, installed the clamp and fired the pump back up. Bleed the air off the top of the filter and was looking at 17LBS of R pressure. I let it run for 10 minutes and it stayed at 17LBS. I then maxed suction to the skimmers and fed a solution of 11#(lbs)of DE and water slowly down the skimmer. I felt 6lbs of DE was just not enouge. I then throttled back the skimmers and blended in some bottom drain. After an hour of running and a full dose of DE the R pressure rose 2LBS to around 20Psi and is holding. NO doubt the grids had been pregnated. The cost of the complete Pentair grid asbly wound up to be 249.00. Lesson learned> running deficient amounts of DE damages the grids and when determining the proper DE amount its better to have a little more than less. Thanks for all of your input, everyone had great information thanks again

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GCAT, I hate to rain on your parade, but that is just too much D.E. for that filter, if you're using a 1# scooper designed for D.E.

If you're using 12 1# coffee can scoops, you may be OK.

Not trying to argue, I just don't want you to have to buy another set before you have to.

If you will post what model, and size filter you have, i can tell you exactly how much you need (via owners manual).

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Here, i'll just post em...

If your grids are swept, with the manifold at the top

http://www.pentairpool.com/pdfs/FNSPlusOM.pdf

If they look like cartridges (still D.E.)

http://www.pentairpool.com/pdfs/QuadDEFilterIG.pdf

If they are swept, with the manifold at the bottom

http://www.pentairpool.com/pdfs/SMBW4000SeriesFilterOM.pdf

Taken from: http://www.pentairpool.com/pool-pro/subsections/filters-de-24.htm

If you have a Sta-Rite, they are on that web site as well.

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No, No, NO Thanks to all you guys, you are wonderfull sources of info and seem to know what you are talking about. I did not use a 1lb coffee can, I did use the scoope that comes in the DE bag. A single heaping scoope contains about 13 ounces of DE by weight,the actual scoop weighs 3 ounces empty. I installed 11 heaping scoops total. Do you still think its to much? It is a FNS plus vert grid, model 180009, FNSP60, salt water pool

Frank

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Not familiar with Jacuzzi filters, but if the 70 stands for 70 sq ft, i would guess 7 lbs.

Not seeing this filter, it's only a guess.

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This is good info. I have a Clearflo Stainless Steel DE 48 sq ft. filter that I believe is impregnated because I also have made the mistake of underdosing the DE. I think my normal running pressure is around 15 PSI (12 PSI without the DE) and I am currently showing 22 PSI. I have BW'd over and over and the pressure comes down to 18 PSI, but then escalates back to the 22 PSI shortly after the addition of the DE. I had the filter broke down before the season started and usually hose off the grids. I also have all fairly new gids. My old ones were original when I bought the house a few years ago and have accumulated tears over the past few years. So, my entire grid is no older than 3 years old. I have 2 questions"

1.) What is PC's opinion as to the best way to clean the impregnated grids.

2.) My manual bleed valve on top with the pressure gauge is cracked and leaks water. I can't seem to locate an on-line vendor who can replace this. Most of the time I see replacement parts for the Pentair's and Pac-Fab's, but the parts diagram does not look exactly like what I have. Any suggestions?

Much thanks!!

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There are several products out there to clean grids chemically. I have used muriatic acid before. A long long time ago, and don't remember the acid to water ratio. Perhaps someone that does this often, can chime in here and let you know.

I think this is your filter?

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There are several products out there to clean grids chemically. I have used muriatic acid before. A long long time ago, and don't remember the acid to water ratio. Perhaps someone that does this often, can chime in here and let you know.

I think this is your filter?

That diagram is similar, but the valve on top looks bigger than what I have and I have no #38. Also, my Clearflo has a brass stem (nipple) with a hole through it that protrudes through the SS tap half of the canister. My plastic valve then screws onto the brass stem (nipple). Perhaps, the replacement/aftermarket part replaces the brass stem also.

I'm confused about the acid. I thought I read somewhere not to use acid.

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To clean individual grids, see Step 1, Section H, CLEANING FILTER ELEMENT.

a. A stiffening of the fabric caused by mineral deposits is usually referred to as "liming up". It usually is due to deposits of either magnesium or calcium or both. Removal of these deposits may be accomplished by soaking the filter elements in six (6) parts water to one (1) part hydrochloric acid (muriatic acid).

b. Wear rubber gloves and eye protection when mixing the solution, and handling or rinsing the filter elements.

c. Soak for at least four (4) hours in a plastic tub or pail.

d. Rinse filter elements thoroughly in tap water.

http://www.pentairpool.com/pdfs/FNSPlusOM.pdf

D.E. filters filter the water down to 1-3 microns, every time the water passes through the filter. Maintain a balanced clear pool and this will reduce incidents of rapid pressure rise. One possibility is that the filter grids or Flex tubes are clogged with minerals or oils. You should clean your grids once a year, or season, with a degreaser and if needed an acid bath. Minerals and oils embed themselves in the fabric of the filter and reduce the available surface area used for filtering.

http://www.haywardnet.com/contactus/faqs/viewfaqs.cfm?category=3

Remove the cartridge from the filter housing following the manufacture’s instructions.

Use a garden hose with a straight flow nozzle to wash down the filter element. Work from the top down, holding the nozzle at a 45 degree angle, and wash all the pleats with emphasis between pleats.

Rinse until all dirt and debris is gone.

For all spa cartridges and elements used in swimming pools where perspiration, suntan lotions, and other oils are present, soak the element for at least one hour (over night is more effective) in (1) a commercial filter cleaner; or (2) one cup trisodium phosphate (TSP) to five gallons water; or (3) once cup dishwasher detergent to five gallons of water.

Rinse the cartridge again to remove oils and cleaning solution.

If the filter has a coating of algae, calcium carbonate (residue from calcium hypochlorite), iron, or other minerals, soak the cartridge in a solution of one part muriatic acid to twenty parts water until all bubbling stops.

WARNING: Failure to remove all oils and cleaning solution before acid soaking will result in a permanent restriction of water flow and cause premature cartridge failure.

Rinse the cartridge clean an reassemble housing.

http://www.unicelfilters.com/pool_owners/ci_chlorine_users.asp

I recommend using the Unicel filter cleaning procedure. It's for cartridges, but the procedure is the same.

You should buy a 1-pound DE scoop from the pool store to ensure that you are adding the correct amount of DE.

Note: The 1-pound Hayward DE scoop has a volume of about 48 fluid ounces. That works out to about 2.67 pounds per gallon or about 20 pounds per cubic foot (apparent bulk density).

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That diagram is similar, but the valve on top looks bigger than what I have and I have no #38. Also, my Clearflo has a brass stem (nipple) with a hole through it that protrudes through the SS tap half of the canister. My plastic valve then screws onto the brass stem (nipple). Perhaps, the replacement/aftermarket part replaces the brass stem also.

I'm confused about the acid. I thought I read somewhere not to use acid.

If you have the brass nipple, then yes, you can use the generic air relief w/gauge.

I wouldn't use strait acid, just dilute it, at least 4:1.

If you want to acid wash them, you should first follow the clensing instructions set forth by Unicel. (Quantum's' previous post)

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I would recommend starting with a 20:1 acid mix and only increasing the concentration if necessary. Acid will reduce the life of filter grid fabric so you want to minimize the exposure as much as possible.

After using acid, you should neutralize it with either sodium carbonate or baking soda before discarding it.

4.57 pounds of sodium carbonate (aka "Washing soda") will neutralize 1 gallon of 31.45 % muriatic acid.

Na2CO3 + 2HCl --> 2NaCl + H2O + CO2

7.33 pounds of baking soda will neutralize 1 gallon of 31.45 % hydrochloric acid.

NaHCO3 + HCl --> NaCl + H2O + CO2

Be careful when neutralizing. The carbon dioxide bubbling will tend to cause the mixture to foam. Add the baking soda or sodium carbonate slowly while stirring. If you add too much too fast, the mix could create enough foam to overflow the bucket and cause a big mess.

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