Filter seems to clog after a couple hours

Oct 2, 2015
10
CA
We bought a new (to us) house in October and now I am finally able to get around to getting the pool functioning. The frogs we getting ready to take over. Here are the details about the pool:


33k gallong
Pentair IntelliFlo 3HP variable speed pump (I replaced the old one since it was 20 years old and all the seals were leaking)
Polaris 3/4HP booster pump for Polaris 280 cleaner (both of these are also brand new)
Nautilus NS DE filter (I cant tell what size it is but I think its around 50 sq ft)
There is also a spa that spills into the pool but there is not heater and looks to never have had one installed


If I take the filter out and rinse it off I will only get 2-3 hours out of it before I start to not get anything back through the return lines. If I look into the pump basket the water will not be to the top as if it's not drawing enough water. If I backwash the filter I will get another hour or so out of it before the same thing happens again.

Just to try it out I ran the pump without any DE after I cleaned it and it seemed to run longer, maybe 4 or 5 hours, before this happened.

So is this a filter problem or is it a suction problem? Or something else?
 
Hello and welcome to TFP! :wave: If your pump basket is not filling up to the top (priming), that's an issue that needs some attention. Folks with a suction-side air leak often see the pump basket water level drop and/or perhaps some air bubbles coming out from the return jets. Have you tried everything listed on this page: Pool School - Suction Side Air Leaks It would be good to resolve any such pump priming issues to ensure you are receiving good water flow to your filter. Once we know your filter basket is staying full and pump fully primed, we can focus on the filter.
 
Hello and welcome to TFP! :wave: If your pump basket is not filling up to the top (priming), that's an issue that needs some attention. Folks with a suction-side air leak often see the pump basket water level drop and/or perhaps some air bubbles coming out from the return jets. Have you tried everything listed on this page: Pool School - Suction Side Air Leaks It would be good to resolve any such pump priming issues to ensure you are receiving good water flow to your filter. Once we know your filter basket is staying full and pump fully primed, we can focus on the filter.

I will check around the pump for leaks tonight.

Just a note however, if I turn the pump off and back on it will prime itself and still get no flow out of the return line. It's only if I backwash and/or spray off the filter that I get flow.


Welcome to TFP. Congrats on the new pool!

Most likely it is algae clogging the filter. Nothing clogs a filter faster than algae.

Get one of the Recommended Test Kits, I use the TF100 from TFTestkits.net.

When you get it give us some test results and get ready to SLAM Your Pool.

Here are some of my fave Pool School articles to get you started.
TFPC for Beginners
ABC's of Pool Water Chemistry


Thats what I thought at first, but a lot of the algae is gone. The water is still pretty cloudy though, still cant see the bottom of the deep end.
 
  • Like
Reactions: Jessie61195
Just a thought but have you tried the air relief valve on the filter after a period of time? When you get the system running to what appears correctly make sure the air is let out of the filter. Open the air relief valve with pump on, it will expel air and spurts of water as the air is released. When you have a steady stream of water for 30-60 seconds you know it's just about all gone. Wait a half hour and open the relief valve again. If it's very minimal to no air that's expected but if you get a rush of air for 5 seconds or more it would seem that air is getting back in from somewhere. No flow out of return is troubling but if the filter is really dirty it can drastically reduce flow. I had a tough opening one year and I had to keep cleaning my cartridge filter very often (twice a day). I would have cleaned it like 3 or 4 if I was home (was working). It took several days of this to clear the pool. When it got super dirty the return line was barley pushing out water (though I had no air issues with the pump).

I did have air in my pump once and I couldn't figure for the life of me what was wrong. Turned out that it was a corner of wood molding scrap that must have flew off my upper deck, landed in the pool and floated into the skimmer. It wedged in bottom of the skimmer and was reducing flow. I couldn't see it until I stood directly over the skimmer and looked down the hole (after spending a 1/2 hour thinking it was other things). I was having my kitchen redone and they were cutting the wood on the deck. Goes to show it could be almost anything causing issues.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Keep rinsing it every 2-3 hrs (or as often as you can) to keep the pressure down. I'm assuming it's green based on the frog comment in the original post. It's gotta be so dirty and that's why is going up to 20 given that it comes back down when you backwash. But first test and post results like pooldv said. Until then it's just guessing. They will fix it with that info. :)
 
I'm late to this thread but two things come to my mind....

1. I am not a DE guy but I do not think a DE filter should be operated without DE

2. If your filter clogs very quickly with DE, it is doing exactly what it is intended to do.....filter impurities from your water. That is almost surely an algae bloom but the next step in order to progress is for you to post a full set of test results......that should confirm or at least give us a clue as to what is in your water.
I will admit that most times I just glance at the pressure gauge and I dont really remember.
the gauge will tell you a lot about your pool. check it often and learns what the changes mean.
 
I was able to get out there today and get some more cleaning done. I am just able to see the pool cleaner in the deep end now.

I started by rinsing off the filter and charging it. PSI was about 10. After about 2 hours the PSI had risen to 21 and flow had pretty much stopped. After a backwash the PSI only dropped to about 15. I didnt seem to get the air issue today though.

I feel like I am spending a fortune on DE. A friend told me to just get a cartridge filter. Anyone have thoughts on that?
 
You will get lots of thoughts on Sand vs Cartridge vs DE, but here is my personal take, would you prefer a filter like your DE filter that catches a lot of suspended particles quickly (ie clogs up in 2-3 hours) vs one that takes days to catch the same amount of suspended material.

Think of this like a vacuum cleaner, do you want one that catches tons of dirt and must the emptied often or one that catches very little and leaves a cloud of dust behind.

p.s. As to the algae issue if you still have live algae in the pool there is no way to filter it out faster than it can reproduce, it is a loosing battle. Instead you need to kill it all then filter out the remains.
 
I don't think you have a filter problem. Like Dave said, the filter is doing what it is designed to do, filter impurities. Even a little algae will clog a DE filter quickly.

No, I don't agree with your friend. When you get down to it, DE filters will filter much finer particles than other filters, that's why it's clogging - again, it's doing what it's designed to do.

Filters will never solve a problem with algae. That is what chlorine is for.

We base our pool care system on accurate testing and only adding what the pool needs, when it needs it. To do that you need your own accurate test kit. Order a TF100 and at least include the XL option. That will give you what you need while you are clearing the pool, and probably enough reagents for a couple of years normal use.

While you wait for it to get delivered, you have a homework assignment. Start with Turning Your Green Swamp Back into a Sparkling Oasis

Resist the urge to take a sample of water down to your local pool store. Not much credence is given to pool store testing around here. While you would think that a "professional" would be the best, unfortunately in most cases it is quite the opposite. Between employees who blindly trust the word of chemical sales representatives and high school kids working in the pool store for the summer you end up with poor results from their testing.

I would also recommend a little more reading, so start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool

So, welcome to TFP!!
 
I will post some test results tonight after I am able to get home and do the tests. I am still getting frogs in the pool. I tested a few days ago and FC was about 16. I didnt think they could live with that much chlorine.

The filter is still clogging up pretty quickly. However I can now make out the main drain in the deep end so I am making some progress.
 
I will post some test results tonight after I am able to get home and do the tests. I am still getting frogs in the pool. I tested a few days ago and FC was about 16. I didnt think they could live with that much chlorine.

The filter is still clogging up pretty quickly. However I can now make out the main drain in the deep end so I am making some progress.
Did you get an accurate test kit and are you following the SLAM Process?
 
For the most part. I have been slacking on checking the FC but mostly because I cant sit by the pool everyday. I have been brushing the pool and cleaning the filter daily. I have a Taylor K 2006 test kit.
It works best when you can follow the process. If you are not keeping at or slightly above shock level then you are not going to kill the algae fast enough. That allows it to reproduce, even in high chlorine. Most people who work test in the morning before work and adjust to shock level, again when they get home and again just before bed. The key to everything we do here is based on accurate testing and reacting to the levels found. Can yo post a full set of test results?

If you just have a K-2006 you may want to go ahead and order more DPD powder and reagent, but the K-2006-C may have enough.

Oh, and back to your frogs. When my CYA was in the mid 200's I kept my FC at about 23. I had a frog that visited every night for a swim. Never seemed to bother him and he was always able to leave me a nice present at the bottom of the pool.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.