Pool Vacuum Fail: The Hidden Problems Killing Your Suction

No suction on a manual pool vacuum can turn a simple cleanup into a frustrating guessing game, especially when the skimmer looks like it’s working. We break the problem down into a field-tested troubleshooting order that saves time: confirm real skimmer suction safely, then use the filter pressure gauge (PSI) as your truth meter for flow. When pressure is high, suction is usually low, and a dirty DE filter, loaded cartridge filter, or sand filter that needs backwashing can be the whole story.

From there, we get practical about the stuff that quietly steals vacuum power. Variable speed pump settings matter more than most people think, and low RPM can make a vacuum head feel useless. We also cover suction split issues, like a suction-side cleaner on a side port, two skimmers pulling at once, and a main drain line that competes with the skimmer. You’ll hear a simple workaround pool pros use when there’s no valve to isolate lines: the tennis ball skimmer plug trick to concentrate suction where you need it.

Then we go deeper into the harder diagnoses: air leaks that only show up when you add a long vacuum hose, what PSI fluctuations mean, and an easy “plastic bag” test that can help confirm a leak at threaded fittings or unions. We also touch on impeller clogs, pump lid O-ring issues, worn filter elements, and when it makes sense to switch to vacuum alternatives like a Bottom Feeder, Vac Daddy, or portable pool filtration vacuum to get the job done even with aging equipment.

If this helped, subscribe for more pool service troubleshooting, share it with a tech who’s been fighting low suction, and leave a quick review with the weirdest vacuum problem you’ve run into.

We walk through a practical checklist for fixing weak or no suction when manually vacuuming a pool through the skimmer or a side port. We show how to spot flow problems fast by reading the skimmer, the filter pressure gauge, and the equipment pad clues that point to leaks, restrictions, or missing parts.  
• checking for real skimmer suction without risking your fingers  
• using filter PSI to diagnose low flow across DE, cartridge, and sand filters  
• increasing variable speed pump RPM for stronger vacuum pull  
• stopping suction loss to a suction-side cleaner and side port  
• concentrating suction with two skimmers using a tennis ball plug  
• turning off the main drain to maximize skimmer vacuum power  
• identifying missing diverter valves in older one-hole skimmers  
• recognizing air leaks by fluctuating PSI when the vacuum hose is connected  
• confirming a suction leak with the plastic bag sealing trick  
• clearing impeller debris and restoring prime and pressure  
• fixing vacuum loss with pump lid O-ring lube or replacement  
• upgrading worn cartridges or DE grids to restore suction  
• using Bottom Feeder, Vac Daddy, or portable filtration when equipment is weak  
Learn more at swimmingpoollearning.com.  
you can learn more at PoolGuyCoaching.com.  

Support the Pool Guy Podcast Show Sponsors! 

HASA 
https://bit.ly/HASA

The Bottom Feeder. Save $100 with Code: DVB100
https://store.thebottomfeeder.com/

Try Skimmer FREE for 30 days:
https://getskimmer.com/poolguy 

Get UPA Liability Insurance $64 a month! https://forms.gle/F9YoTWNQ8WnvT4QBA

Pool Guy Coaching: https://bit.ly/40wFE6y

Transcript

SPEAKER_00 1:02

Hey, welcome to the Pool Guy Podcast Show. In this episode, I'm going to go over some things that happen when you go to manually vacuum a pool using the pool's filtration system to the skimmer, and you have no suction or very little suction when you go to vacuum that pool using a manual vacuum hose, a vacuum head connected at the skimmer or side port of the pool. Are you a pool service pro looking to take your business to the next level? Join the pool guy coaching program. Get expert advice, business tips, exclusive content, and get direct support. From me, I'm a 35-year veteran in the industry. Whether you're starting out or scaling up, I've got the tools to help you succeed. Learn more at swimmingpoollearning.com. The first thing to note is if the pool actually has suction at the skimmer. This is really important, and you don't want to cause yourself

Welcome And The Suction Problem

SPEAKER_00 1:51

any harm by doing this either. And a lot of people will just stick their hand in the skimmer hole when the skimmer is on. Sometimes the suction is pretty strong, so you want to be careful doing this. Visually is probably the easiest way to see if the skimmer is actually working. Look at the skimmer, and you should see the water swirling and being pulled

Coaching Program Quick Mention

SPEAKER_00 2:11

into one of the skimmer holes in there. And again, a lot of pool pearls will just stick their hand in there. It's not really a careless maneuver, but it can be dangerous if there's a lot of suction and it could suck your finger down. Sometimes there's tremendous suction there. So you should be able to tell again, just visually looking at the skimmer, if

Confirm Skimmer Suction Safely

SPEAKER_00 2:31

there is suction. So that's the first thing that I would recommend doing is to make sure that there is some kind of suction going on. The other thing to check right away is the pool filter pressure. So once you turn the system on, there's a gauge on top of the filter and it's measure it measures the pressure in the filter or psi. The more pressure there is, the less flow there's going to be to the pool or back to the return line, and the less suction there's going to be also. So let's say for a D filter, typically a clean D filter would be at 20 psi. If that filter goes to 30 PSI, chances are you're not going to have a lot of water flowing and a lot of suction because of the pressure in the filter and the poor flow. Cartridge filter is a little harder to gauge, but if there's a if it's a single cartridge filter, you also will notice a big drop-off in flow and suction when it goes from you know 20 to 30 psi.

Filter Pressure And Pump Speed

SPEAKER_00 3:27

And the same thing with the sand filter. So those are the two things to note right away when you're going to vacuum a pool and you're getting no suction or it looks like no suction is happening. Check those two things, and that's the main thing that I check right away. And then I'll go and troubleshoot other aspects of it at that point. I should mention that if you are using a variable speed pump, that you're going to have a lot less suction on the low RPM. So that's something also to note. If you're at a pool and the pool is running at 2400 RPMs, you may notice that the vacuum suction is a lot lower. Then if you were to put it in maybe quick clean mode or timeout mode and turn that up to 3450 RPMs, which is the full speed of a single speed pump, this will get you a lot more suction. So if you notice that you're not pulling a lot of water because of that reason, it could be that the variable speed pump is set too low, and you want to, of course, use it at at least 3150 to 3450 RPMs or 3400-3300 RPMs, and that will give you really adequate adequate suction. Another thing that could hamper the suction when you're vacuuming is if you have an automatic suction side cleaner connected at the side port of the pool. The side port will split some of the suction. And a lot of times you can vacuum the entire pool using the side port anyway without using the skimmer. You just take the cleaner head off, put your vacuum head on, connect the cleaner hose to it, and you can vacuum with it. It won't be as full suction as with from the skimmer, but if you do need to use the skimmer with the vacuum hose and you have a suction side cleaner at the side port, it's a good idea to turn the side port off so that you have full suction at that skimmer. Another thing also to note is that if there's two skimmers at your stop, both skimmers will probably be activated at the same time. If you put the pool hose in one skimmer, you're not going to get a lot

Suction Split From Side Port

SPEAKER_00 5:21

of suction because the other skimmer is still wide open. An easy trick for this and something that a lot of pool pros use. So you're not going to look, you're not going to the equipment area and turning off a skimmer looking for the valve. And a lot of these two skimmers configurations don't even have any kind of valve to turn off one skimmer anyway. So the best thing to do is take a tennis ball. I like using a newer tennis ball, they seem a lot better than the older ones. They start to lose some of their firmness. And a new tennis ball, put it in the skimmer hole that you want to block off. The skimmer hole that's not being used by the manual vacuum hose. Put the tennis ball in there, and then you can vacuum with no problem. It's gonna put the full suction to the other

Two Skimmers And The Tennis Ball

SPEAKER_00 6:06

skimmer because one of them has a tennis ball in it, and then the other one will activate completely. And sometimes this the change in pressure is pretty tremendous when you do that. You also want to make sure the main drain is off. I had this old account that had these really old valves on it. It looks like a submarine type thing where you spin these really old valves, and you'd always have to turn the main drain off with one of these valves by spinning it. And it actually sounded like a submarine movie when you were closing the valve off. But if the main drain is open attached to a valve, maybe not quite such an old valve, but any kind of valve that is controlling the main drain, you know, any kind of Jandy valve or teger valve, you want to make sure the main drain is completely off and you go to vacuum from the skimmer. You want the skimmer to have complete power when you're sucking when you're vacuuming from the skimmer using the manual vacuum hose and vacuum head. So make sure the main drain, the suction is off at the main drain as well. If the pool that you're trying the manual vacuum

Shut Off The Main Drain

SPEAKER_00 7:04

from is pretty old, it may have an old Anthony skimmer, and there's actually a diverter valve that actually goes in there. I think it's the V34124 valve pack Anthony pool skimmer, and this is one of the ones that they have. It's kind of threaded. They also have a if you have an old Penter Admiral skimmer, they also have a valve for that as well. These are inserts that actually should be in the skimmer that actually changes the flow from the skimmer to the main drain. The Penter one is the 85002600 Penter Admiral Pool Skimmer Diverter. This one's not threaded like the other one. So those are highly necessary for you to vacuum with one of these old skimmers. If you look at the hole and there's nothing in there, but it looks like there should be something

Old Skimmer Diverters Missing

SPEAKER_00 7:50

there. Maybe there's some notches on the bottom of the skimmer. It's probably missing the diverter, the pool skimmer diverter valve that goes in there, and you're not going to get full suction because without that diverter valve, it's going to suck from the main drain as well as the skimmer at the same time. And this is really crucial if you have a suction side cleaner connected at the skimmer. You want to make sure you have this pool skimmer diverter valve in the skimmer itself. Again, this is for the older skimmers. You should have this in there, and it's usually a one-hole skimmer that holds directly in the center. And this is kind of the giveaway that it has in one of these diverter valves because the other skimmers that use the float diverter valve, which is the UFO-looking device, have two skimmer holes in it, not one skimmer hole. So if you have a one-hole skimmer and you connect the vacuum hose to it, you're not getting any suction or very little suction. My guess is that you're missing the diverter valve that belongs in the skimmer hole that controls again the suction from the main drain and skimmer. Once you put that in there and turn it, you're gonna see a tremendous amount of suction going to the skimmer. And you want to leave it probably at the full skimmer suction going forward. So that was my kind of rapid fire why your pool has no suction when you're vacuuming the pool. I wanted to do that quickly so that you can get all of these kind of main troubles out of the way, and then we can dive a little deeper into some maybe some things that are a little bit harder to diagnose that's going wrong with the pool. I'll start with the first one. So all the ones I mentioned that should solve most of the problems with not having suction to the to the pool hose vacuum head when you're manual vacuum the pool. Something else to consider is that maybe the pool has a vacuum leak or a suction leak. A good way to diagnose this is that when you plug in your pool hose into the skimmer, the PSI on the pressure gauge goes from 20 down to 10, down to 8, down to 5, back up to 15, back up to 20, then back to 10, down to 8, maybe back up to 20 for a few seconds. It kind of fluctuates, and this will indicate, in my opinion, that there's an air leak or there's some air getting into the pump somewhere, either at the pump lid, maybe at the threaded fittings, maybe at a union or the o-ring needs to be changed in there. But if there's air getting in there, what happens is that you have a 50-foot pool hose connected to the vacuum head, you have it connected to the skimmer. That extra length of pool hose is really going to exasperate the air leak, and it's going to make it pretty much impossible for the pump

Air Leaks And PSI Fluctuations

SPEAKER_00 10:51

to pull the water from the bottom of the pool from the vacuum head all the way through the pool hose into the pump. And it's you're going to see that fluctuation and suction and the pressure gauge going up and down because of that. Once you unplug the pool hose, the skimmer should activate completely and you're going to get 20 psi on the filter with no fluctuation. That indicates a small suction leak. This also will affect the suction side cleaner if you have it connected at the side port or the skimmer. A suction leak like this will also cause the ambag cleaner to work, then stop, then work again, then stop and work again. It's kind of like a little cycle that it goes through. There's a plastic bag trick that I I have a video on that I use. Now in California, the plastic bags that I like are really in, they're really pretty much gone off the market. We were not allowed to have these kind of plastic bags anymore at the grocery stores. The state has mandated it. But Home Depot still has these bags. So if you go to Home Depot and you go to check out, you can get the plastic bags that I talk about. They're really thin plastic bags. Not the thick plastic bags you would get from like Sprouts or maybe Albersons. They're kind of thin. And you can tear these and you can tie them around the inlet and outlet of a pool pump. Now, this sounds weird, but if you tie these plastic bags around the inlet and outlet, this will seal any kind of air leak and it'll allow you to have full suction. So a good way to diagnose and to really identify an air leak. Now there's other ways. I think people like matches and see if the smoke gets pulled

The Plastic Bag Leak Test

SPEAKER_00 12:23

in. Or if you spray it, you might see air bubbles. I think the plastic bag trick is probably the easiest thing to do. Just tie the threaded area coming out of the pump and coming into the pump with a plastic bag, and then attach your vacuum hose to the pool and see if it holds this suction. In most cases, it probably will, and that will indicate that that threaded area of the pipe has kind of melted a little bit, and some air is seeping in there and getting in there and causing that to happen. Another problem we may run into is that there may be some debris in the impeller. Now there are other symptoms that you'll notice right away when there's debris in the impeller, but you will also notice that you're going to have really poor suction when you go to vacuum and pool. The best way to check this is to turn off the pump, take off, take off the pumplet, take out the skimmer basket. And I like I like using a flathead screwdriver, and I'll just take the flathead screwdriver and I'll spin the impeller with it. I'll stick it in there where it's at the bottom where you remove the basket. There's a small little opening. Stick it in there and spin the impeller. And if you start to hear a gurgling noise, that means that you've loosened up some of the debris in there. Fill it back up with water, put the pump basket in. Turn it on, and you probably will get full psi at that point or full pressure from the filter. And again, you'll notice pretty much right away when you get to the equipment area. If there is

Debris Stuck In The Impeller

SPEAKER_00 13:47

something jammed in the impeller or causing it or debris stuck in there, it's gonna cause it to have lower psi in the filter. So normally if it's at 20 psi and it's at 10 or 12, just a good indication that there may be something stuck in the impeller. Also in the pump basket itself or pump pot, you won't see it totally full with water. The pump lid overing could also be a problem. Now, under normal circumstances, without the vacuum hose connected to it, the pump may be full of water. When you connect the vacuum hose to the skimmer, the pump may only be halfway full of water and you may lose some pressure in the filter. One thing that I like to do in that case is I'll just take I'll turn everything off, I'll take the pump blit off, I'll either change the O-ring if I have one that matches it, or I'll get some magic lube and I'll lube up the O-ring really good and put it back on. And a lot of times the extra 50 feet of length with a worn-out O-ring on top of the pump will cause it to lose pressure, lose suction. So once you loop up that O-ring or change the O-ring, it definitely will have a pretty good effect on it, and you should be able to get full suction when you go to vacuum the pool now. Again, I'll

Pump Lid O-Ring And Dirty Filters

SPEAKER_00 14:59

back up a little bit back to the beginning. If the filter is dirty and you backwash it, you should be able to get pretty good suction. If it's a cartridge filter, clean the filter. But a dirty filter will definitely affect the amount of suction you're gonna get at the skimmer. And then to compound that, a filter with really old elements, let's say you have a cartridge filter, a single cartridge filter, and the cartridge hasn't been changed in a year or two. I would bet that changing that cartridge filter will have a dramatic effect on the pool suction, and you're gonna see the skimmer activate tremendously at that point. Same with the quad type cartridge filters, if they're worn out, the bands are broken, all the pleats are stretched out. Changing those four cartridges is gonna really make a big difference in the suction of the pool. And with the D filter, if the D grids are really old or if the D filter is really dirty, it's gonna have the same effect. Backwashing it sometimes will cure that. Taking it apart and fully cleaning it, changing out any grids you need to change will also allow you to have a lot more suction. And I guess finally, I should say that there are alternate methods than using a manually vacuum hose and vacuum head to vacuum out a pool. There's the bottom feeder with the Carter's filter adapter or assembly, I should say, and this will allow you to vacuum dirt out of the pool down to 10 to 20 microns without using the pool's filtration system. You have the Vac Daddy with the bag that will also act very similarly. We can vacuum all the all the dirt and debris into the bag in the Vac Daddy. You can also use the Vac Daddy to vacuum the waste, but there's also portable filtration systems you can take to the pool, like the advantage porter vac, and these will allow you to use an outside system rather than plugging or connecting the vacuum hose to the skimmer and using the customer's filtration system. A lot of times the pump may be old as well, and if it's an old pump that's not running that well, no matter what you do, you're not going to get a lot

Vacuum Alternatives And Old Equipment

SPEAKER_00 16:52

of suction out of it. So a really old, you know, like you know, stay right dura glass, or I've seen some brass pumps with a similar problem where you're just not getting any kind of suction from the skimmer because the pump is just really old, that's also a factor as well. Really old, a really old pump, a really old filter can't really affect the amount of suction that's generated at the equipment for sure. And so that's also a factor that will need to be addressed. But as I mentioned, there are alternate ways to vacuum a pool without having to actually use the manual vacuum hose and vacuum head and connecting it to the skimmer. Looking for other podcasts, you can find those by going to my website, swimmingprolearning.com. On the banner, there's a podcast icon. Click on that, and there'll be over 1900 podcasts you can listen to at your leisure. And if you're interested in the coaching program that I offer, you can learn more at PoolGuyCoaching.com. Thanks for listening to this podcast. Have a rest of your week. God bless.