DE Filter Needs To Be Backwashed Every Hour

I have a Hayward DE pool filter and I have to backwash the filter every hour.

After backwashing in runs well and within fifteen minutes it clogs up and I have to do it again.

What could be the problem? I have a professional working on it but it's not working right.

Thanks for the question

I will assume when the filter clogs up the pressure rises. It could be a few things. Here are related posts about that:

Pressure Builds Up In 30 minutes And DE Flowing Back Into The Pool

Too Much DE Filter Pressure

D.E.Filter High Pressure

Here's a summary of the pages above:

- Use a real DE scoop and not a coffee can. Using anything other than a DE scoop will give you either too much or too little DE.

- Be sure the impeller is not jammed up with debris

- Check the pressure gauge and be sure it's working properly

- Is the water dirty or in the middle of an algae bloom? This will clog up a DE filter quickly, but it's normal. A DE filter will catch alot of debris.

- Be sure the grids are properly cleaned and free of tears and rips

- Make a slurry of DE BEFORE putting it in the skimmer. Many people just dump the DE in. This can cause big chunks of DE sticking to the grids.

- Important... Use the right amount of DE. With the filter pump running, slowly add about 1 pound of DE for every 10-12 square feet of filter space. Basically it's this: 48sf. DE filter = about 4 pounds of DE. (check your owner's manual for details and exact specifications)

Again, and this is important...use a DE scoop, NOT a coffee can or something similar

If your pool guy is using a coffee can, either tell him to use a DE scoop or get rid of him and get someone else in there. If he gives you the "It's the same thing" routine, he's not a real pool guy. The real pool guys like myself will take an extra 30 - 45 seconds and do it right.

Look over the pages and information above and if you still have questions please feel free to contact me through this post.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "DE Pool Filter" category.

Swimming Pool Questions & Answers

Check back to this post for updates or answers.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of your choice and I'll answer your questions by phone.

Contact Me


Hope this helps and have a great Summer.


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Backwash Valve

by Rachel

The backwash valve has open > and < close. What does this mean?

I know you raise the valve to begin backwashing, however, you can also turn it.

Thanks for the question Rachel

My first question is do you have a push/pull valve?

Many of these you need to hold the T-handle, give a slight twist, and pull up. This allows the water to enter the top pipe, or bulkhead, in order to backwash. The bottom goes out to waste.

To close, you simply push down on the valve, twist, and close. I believe those are the arrows you're referring to.

When in doubt you can also check with the manufacturer of the valve or your owner's manual.

As long as you're doing a proper backwash by pulling up on the handle, turning off the pump, then pushing down to filter, you shouldn't have any problems.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "DE Pool Filter" category.

Swimming Pool Questions & Answers

Check back to this post for updates or answers.

Hope this helps.


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Totally Basic DE Filter And Valves For A Swimming Pool

by Carolyn
(Dartmouth, MA USA)

Last year my opening my pool took forever and the problem ended up being broken ribs in the filter. Eventually everything was taken care of, but I find myself second guessing everything this year. My pool is inground with a vinyl liner. 20' by 40'.

I have a Haywood pump and use DE. I have a main drain and three skimmers. The pool holds 35,000 gallons. I feel a bit foolish going back over this, but would you please go over which skimmers need to be open or closed for cleaning, vacuming to waste, general running etc.

Thank you

As foolish as this sounds, this is really what I need. Love this site!!!

Thanks for the question Carolyn and I'm glad you like my site.

I will assume you have a good understanding of pool chemistry and how to balance out the chemicals. so I'll just stick to the filtration side, as the question says. A answered a similar question about valve positions in this post:

Bottom Drain Valve And Pool Water Pressure

It's worth a read. Like the above post says, it's difficult to say which skimmers need to be open all the way, which ones only 1/2 way, etc... because each situation is different.

I had a pool in Arizona that had 1 large palm tree right over the deep end. All the bird dropping and everything else that can fall from palm trees fell into the deep end of the pool, so the skimmer in the deep end got a good work out. The one nearest the shallow end stayed pretty clean, so I increase the suction to the deep end skimmer.

I had another pool with barely any landscaping, but lots of rocks and dirt, and it had pop-up floor cleaners. I decreased the skimmers and increased the bottom drain because the skimmers didn't have much debris from week to week. It's all about what balance your pool needs for cleaning and proper water flow.

On the filtration side, you can close all but one skimmer when vacuuming to WASTE. This will give the vacuum the most suction and speed up the vacuuming process. You might not need to go over the same spot 2 - 3 times before it's clean. But remember to keep an eye on the water level as it will drop quickly when you do vacuum to WASTE.

Keep the level between 1/3 - 1/2 up from the bottom of the skimmer. I wouldn't suggest closing the bottom drain. The smaller the hole, the faster the water goes through. A simple law of physics. You run the risk of tearing your DE grids or not having enough water flow through the system.

Again, it's about balance. If it's just normal weekly cleaning, I would recommend vacuuming to FILTER, but if you have heavy cleaning or a bad windstorm, going to WASTE would probably be the best bet. Your main time will be on the FILTER cycle. Run it 10 - 12 hours in the Summer.

I know in Mass. you close the pool for the Winter. If your system is equipped, after backwashing you'll need to RINSE. This gets out the left over dirt and debris in the line after you backwash. Some good pages for DE filters are these:

DE Pool Filters

DE Pool Filter Maintenance

You might want to see which skimmers need to be open 1/2 way or all the way, including the bottom drain valve. Take a look at your pool. Look at the landscaping. Where is the dirt coming from? Where is it settling? Are there any flowering plants around? Where are they in relation to the skimmers?

Are the trees closer to the shallow end or the deep end? Ask yourself these and similar questions, then make the right adjustments to your valves. It may take a few days to get it right, but you will. Hope this helps and if there's anything else, please feel free to contact me.


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FSN O-Ring...Band Assembly/Belly Band Clamp Leaking On DE Pool Filter

by Bob Proietto
(Guilford ct)

I have a Pac Fab FSN 60 DE pool filter.

I have a leak at the O ring band assembly.
The O ring has no nicks and I use a magic lube lube.

How often should these be replaced?

It was fine and then I disassembled to clean and now cannot stop it from leaking.

Thanks for the question Bob

Most DE filters have a belly band clamp with a large O-ring/gasket between top tank and bottom tank.

The O-ring can loosen, come out of the track, become distended or flattened if it's not placed correctly. It may need to be replaced if water is leaking from the center clamp.

Be sure you're putting the top of the tank on the bottom exactly as it should be. Sometimes I had to wiggle it a bit, or slide the top back and forth just a hair to allow the top of the tank to seat correctly on the bottom.

Having a pinched O-ring is the most probable answer, or it's not seated correctly.

There's no harm in replacing the O-ring, but you want to be sure the one you have is in good condition before spending any money. No tears or rips.

Be sure to clean the O-ring very well. Any dirt particles and you might not get a good seal.

If your DE filter tank is leaking, not the belly band, bulkhead fittings or air bleed assembly, you'll probably need to replace the leaking tank half or the entire filter.

Unfortunately there's no way to repair tank damage.

Hope this helps and have a fun and safe swimming season.


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