For a piece of equipment that is not electrical, digital, or highly complex, a pool filter can still cause a great deal of pool owner stress. You might be surprised how many questions we field regarding what is essentially a big tank that water passes through. But since that tank is so vital to the operation and safety of your pool, I wanted to share the some of the most common issues our techs encounter and how you might troubleshoot some basic problems.
#1 The Spider Gasket
Inside the multi-port valve on DE and sand filters, you will find this gasket which somewhat resembles a spider web, featuring a small center ring and spokes (typically 4 or 5) that connect to a larger outer ring. For a small, simple part, it can be the source of quite a few filter headaches. Signs of a worn or damaged spider gasket include leakage around the valve or water coming out of the waste line even though valve is set to “filter”. Damage to this gasket is commonly caused by moving the valve handle while the pump is running.
If you need to replace the spider gasket, look at the valve body itself (not the filter tank) for a model or part number. With a valve model number, the correct gasket can usually be cross-referenced. It is worth noting that some manufacturers include the spider gasket only as part of the diverter. In this case, you would need to purchase the entire diverter assembly. If you are unfortunate enough to find yourself in this camp of filter owners, you will want to compare the price of the diverter vs a completely new valve.
#2 True Grit
Probably the most ironic of filter problems is sand or DE powder flowing back into the pool. For sand filters, one or more cracked laterals or a broken standpipe is typically the culprit. Replacement laterals can be purchased individually or as part of a standpipe assembly. The standpipe is available separately also, if you determine all of your laterals are in good shape.
For DE filters, you are usually looking at worn grids that have developed tears. While checking the grids, also inspect the standpipe o-ring for wear and tear. Another cause of DE in the pool is simply adding too much DE powder when recharging the grids. Be sure to follow the manufacturer’s instructions; in the absence of an owner’s manual, a general rule of thumb is 1 lb of DE per 10 sq ft of filter area (this refers to the square footage of your filter, not your pool).
#3 Under Pressure
Feeling the pressure of pool ownership? Then you and your filter might have something in common. Some filter problems are caused by excessive pressure build-up inside the tank. High pressure can be caused by having a filter that is undersized for the pump; this means the pump is pushing more gallons per minute than the filter is designed to handle. Another cause is simply a dirty filter with cartridges that need to be rinsed, or sand or DE that needs to be backwashed. If after cleaning, you are still faced with high pressure, there could be a clog in the plumbing lines.
High pressure can cause laterals to crack and leak sand into the pool. It can also be the reason for a cracked tank or even more dramatic, the filter lid blowing off.
#4 Feeling a Little Low
As mentioned above, high filter pressure is a problem but so is low pressure which usually indicates some obstruction of the water going into the filter. This can negatively impact pool circulation. First step – check your pump strainer basket and impeller. If either one is clogged with leaves and other debris, clean them out to increase water flow.
Low pressure can also be linked to the pool skimmer which could have a clogged basket or a weir stuck in the open position (the weir is the flap on the skimmer that sways back and forth). Reduced water levels can also cause low pressure.
It’s worth noting that a broken pressure gauge can give a false reading, high or low. Check to make sure the gauge needle returns to zero as it should when the pump is off.
#5 The Replacements
All your filter might need is new cartridges or grids but good luck trying to figure out which ones you need. This is a very common conundrum. Frequently, the filter manufacturers place a label or plate on the filter tank that lists all the different filter sizes for that particular model. Then they put a check mark or punch out a hole next to the actual filter size. That is, in theory. I hear from many customer that there is no mark or it has worn off over time. There could also be no readable part numbers on the grids and cartridges themselves, leading to a good deal of confusion.
The easiest solution in this case is to measure the actual media. So for DE grids, you would measure the length and width of the full and the partial grids. Most DE filters have seven full grids that are the same size and one partial (shorter) grid. For cartridges, measure the length, the outside diameter of the cartridge, and the diameter of the hole. Often people don’t want to take the extra step of opening the filter to get these dimensions and they take a guess at the correct size. This makes for an awful lot of returns during pool season so I highly recommend doing it right the first time.
Replacing sand can also present a challenge or two. The main question being “how much sand do I need for my filter?” This will be in your owner’s manual but if yours has gone missing, feel free to contact us here as we have specs on many filter models. The manufacturer can also be a resource for the proper sand amount for older, more obscure filters. You will want to check on the recommended sand type as well which is typically #20 or #30 silica sand but does vary per manufacturer.
If you’ve been a pool owner for any length of time, you will not be surprised if you run into other filter problems not covered here. As customers often tell me, “It’s always something!” But rest assured, we’re happy to help you troubleshoot filter problems, find replacement parts, and get you on your way to enjoying that pool.
I’m new to using a cartridge filter. I just starting using a new cartridge and had it running all night. When I checked the cartridge just the bottom was green with algea the top was still clean white. Is that normal? Thank you
If your pump’s flow rate and filter pressure are fine, then there is likely nothing to worry about. The green stain is either from the shell of your filter being dirty, or algae settling to the bottom of the tank when the pump stops and system loses pressure. Water can get trapped in the filter, leaving the filter only partially submerged. Or, you have a high amount of copper in the water, which presents green staining
I get black cloud out of jets on first morning startup wit alot of air. Then black stops and pools runs as normal. Noone can figure it out complete pentair sytem 20k inground pool, de filter,
Have you checked our filter for signs of algae or mold? Do you have a pool heater on the system? Lastly, is the black cloud like a dust or dirt like substance or is it more liquid?
I have a Pentair Tridon II T60 sand filter, only a few days after installation of all new system, there is a hole at the bottom of the filter. The people who installed it for me said that there was a foul play, but the hole was way too big for a drill bit and it would take too much work to make a hole at the bottom instead of on the side of the tank. Please give me your opinion.
Thank you
Hi, I Just replaced my Hayward sand filter, and reconnected/ sealed the pipes because there was an air leak. I have been everything looks like is running fine, but the water is green regardless of chemicals. It is not clearing up even after running it for two days straight. I have backwashed and repeated the process without success. I checked the automatic chlorinator and the tablets had not dissolved in a couple of weeks. I added liquid shock, and after several hours added liquid chlorine. I now have too many chemicals in the pool and it looks the same. Although water is flowing into the skimmer, it doesn’t look like is going to it. I also tried vacuuming and there was suction. What else could it be?
algea???
Hi,
I just replaced my DE filter with the biggest Cartridge filter on the market (Hayward SwimClear C7030). 725 sq. feet.
My pool guy replaced it on Tuesday morning, and as of today (after about 90 of hours of filtering), the pool is still the same as it was on Tuesday, i.e. a little cloudy. I can see the bottom at the deep end, but it’s not crystal clear, and my old filter would clean that easily overnight, even though it was much smaller.
My chemistry is OK. My chlorine was around 5 on Wednesday night, and since it was raining I shocked it, and it was still around 12.5 this Saturday morning, which indicates that I don’t have algae problem.
What could possibly have gone wrong with the filter?
Thanks,
M.
I have an above ground pool with a Haywood De filter.
I am getting DE coming back into the pool from the return line. Does this mean I have an issue with some of the fingers in the filter?
Thanks
Yes. Give this a read for a list of things to check: How To Prevent DE Filter Powder Returning to Pool
My drain valve broke on my sand filer for my swimming pool can I still use it
Is water spurting out of the drain valve? If so, I would cease filtering until it is fixed?
Have you opened the filter to determine if there are any broken pieces or something jammed or blocking water flow? That would be my first move.
Hi! I have a cartridge filter. When I turn on my pump the filter makes a loud vibration sound to the point we have to turn it off. The pump still works during this time and the system still seems to be working. Any idea why the filter would vibrate and make such a loud noise?
I just hooked my filter and pump back up for the season yesterday. The hose that runs from my sand filter to my inlet has came loose twice in the last 24 hours. I have two clamps “securing” it and it still comes off, allowing the water to flow out. What causes that? I labeled all of the hoses…except for one. There’s a small chance that I mixed the skimmer-to-pump hose up with the filter-to-inlet hose…. but they look the same to me. Please help.
If you think you mixed the hoses up, remove them and check that the ends have the same diameter. The end piece you are connecting to the inlet may be warped; in that case, you would need to replace it, and maybe get new clamps as well.
When I put my pump on filter setting it does not work. It’s like it’s running but no water is flowing through it. The other settings work just fine
If the only setting the pump and filter are not working on is the regular filter; that usually means your filter is dirty and needs a thorough cleaning.
We have a DE filter, our pump runs for about 30 mins then the pressure shoots up and flow into the pool slowly goes down to nothing. We’ve bought the filter acid cleaner let the filter fingers sit over night in it. And it’s still doing the same thing. Once we bump it, the flow into the pool is harder for about 15 mins then slowly dies down again. Please help!!!
What model DE filter do you own? Is it a standard grid filter or the Hayward Perflex style?
Hayward preflex extended cycle DE filter
When was the last time the tank was was drained, the old DE and debris cleaned out of it? DE can become so caked with crud that bumping the filter doesn’t do the job anymore.
We cleaned it out the end of last yr before putting it up for the season. It did the same thing last yr but this yr is worse.
So this season we started the pool up and as soon as we got the pool filled and turned on the pump and filter and it started doing the same thing as last yr I went and bought the cleaner and cleaned the filter drained everything out of the pump maybe sure everything was sealed tight and started it back up. But nothing has worked
Put sand filter on backwash runs about ten sec. and stops takes about two min. Does it again.do I need new sand.
Dear sir,
I installed sand filter pool filtering time Why am I getting sand in my pool from the filter? Can you please explain me.
This “Sand In Your Pool?” article covers the common causes.
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Hi my pool filter does not filter but works on every other setting. It also does not make any noise
When was the last time you cleaned, backwashed or replaced the filter media?
Hi Matthew my pool filter runs dry if I attach the pool cleaner (Creepy Crawley) and then it blows back air to the skimmer box when I turn it off. All is fine until I connect the cleaner ???
The cleaner hose has a sucking air leak. Check the hose for pinhole sized air leaks. An easy way to do that is to take each section of hose, seal the end, and submerge it in the pool. Look for any bubbles coming from hose section (not the ends) for the source of the leak.
Brand new tagellus (same as old one that cracked in process of changing sand) brand new sand. Vacuuming green silty algae from pool floor. Blows right back into pool. This is after I have backwashed thoroughly and rinsed thoroughly. Pressure at 10. Only explanation I can come up with is channeling but I just 4 days ago put 300 lbs of sand in and filled tank rest of way with water so the sand settled in nice and dense. Again brand new filter too. Laterals fine. Help!
The filter is not going to get rid of the algae. You need to complete a cycle (or two… or more) of shocking, filtering, and backwashing to get rid of the algae. When the water gets hazy or cloudy white from dead algae, I suggest using a flocculant or clarifier to help the filter catch the silt.
Hi my sand filter only runs for 5 minutes the flow becomes weak and the kreepy stops,but itworks perfecty on cycle.what could it be?
Thanks
This search page gives you a few guides and articles on how to correct low water pressure.
My problem of my sand filter tank lid was frequently blowout and the sand back to the pool can you advise me what is the reason why it happened.
Many thanks,
This sounds like a pressure issue; caused by dirty sand, too much sand, or too strong of a pump.
For dirty sand, backwash the filter thoroughly. if the sand is old, and backwashing doesn’t help you will need to replace the sand. If you have recently replaced the sand and you put too much sand in, then you need to scoop some out. The normal sand level should be about halfway to two-thirds up the tank. if this problem started after installing a new pump, you may be overpowering your filter. If it is a dual or variable speed pump, try the lower speeds. if it is a single speed, then you will need to change the motor and impeller to a lower horsepower.
I have a sand filter that the gauge won’t work but the pressure is good at inlit. When I vacuum algae not sand comes out inlit
Try setting the valve to recirculate to bypass the filter. if the pressure gauge doesn’t read any pressure, then it is time to replace it. If the gauge does give a reading, then you likely have a clogged filter; the clog probably being alive/dead algae. If algae is present in the pool then you need to shock your pool, once or twice.
We have a filter that is only 3 years old. My husband cleans it religiously and maintains everything per the manuals. We recently had all the piping replaced and converted the pool to saline.
All the chemicals are in balance according to the pool store. There is some sand at the bottom of the pool and the pool is cloudy.
We put chlorine granules in the skimmer and they blew out the jets.
Do you recommend replacing the filter or is there another way we can trouble shoot the problem before replacing it?
Sand int he pool could be a of things: you need to change the sand or there is a broken lateral.
If your filter’s running PSI is high, and stays high even after backwashing then you likely need to change the sand. Old dirty sand can lead to channeling which allows dirt to bypass the sand and recirculate back to the pool. Broken laterals can happen with age.
Luckily the fix is the same for both problems, remove the sand. Replace the old sand with new sand. or, remove the old sand, check the laterals, then reuse old or replace with new sand.
It’s a filter system, not a sand one. We pulled apart the housing, took the filter out and then put it back in.
It must have been slightly loose or something because as soon as we did that the filter started working properly and the pool cleared up the same day. 🙂 YAY!
we replased the center tube with the black finger like tubes but sand is on bottom of pool i donot think we put it in right do i start over and do i put the tube in fist and then the sand or a quater of sand and then the tube and the more sand please help the water is clear but when i vaccum it looks like every thing iback becase when i back wash it is clear that inpossible for ipick up alge and it just comes back in and back wash clear HELP
I have a Crystal clear pool sand filter, the tank is made of polyethene and is cracked just under the multiport valve under the flange,. Can it be repaired ?? please
Most of the times trying to mend a filter doesn’t work, but you can give it a try. The most common product I’ve heard used in these situations is JB Weld. We actually cover this topic in a Poolside Chat Episode #20: Should I Fix My Cracked Filter Lid?