Top Pool Sand Filter Problems

Every seasoned pool man has a gut feeling when their pool sand filter doesn’t just feel right or if there’s a problem. But how do we develop this sixth sense of knowing when something is “off”? Well, by familiarizing ourselves with the possible problems that may pop up of course! Today we’re going to go over all of the top sand filter problems, what causes them, and what possible fixes we can do to resolve them.

Sand in your pool

Having a sand filter doesn’t mean that it’s okay to have sand in your pool! Sand constantly entering your pool could be a sign of broken sand filter internals, more specifically the laterals. To check your laterals or standpipe, you will have to empty out your sand filter of its contents. For more information on how to empty your pool sand filter, check out Mr Pool Man’s guide on how to change pool filter sand.

Now, damaged internals for your sand filter cannot be patched up, it would take more effort than is worth it (if the patch job doesn’t hold then you’ll have to empty the sand filter all over again) so getting a new set of internals is highly recommended when you come across this problem.

Note: Many online pool shops don’t sell the internals alone for sand filters as this is a very rare problem. The only time that the laterals can get damaged is when you’re replacing the sand. So if you follow our guide on how to replace the sand filter media properly, then you shouldn’t come across this problem. But if you do, do send us a note down below at our contact form, we might be able to see if we have any on stock in the warehouse.

Water coming out of waste line

Some residual water coming out of your waste line is normal, especially if you have just recently backwashed your filter. But if it’s constantly coming out, then we may have a problem. Water coming out of the waste line is a sure sign of a spider gasket problem on your multiport valve. It could be something else, but nine out of ten times, it’s a spider gasket problem. But to be absolutely sure, you can refer to Mr Pool Man’s Multiport Troubleshooting Guide to completely check your multiport to check everything at one go.

Sand Filter not filtering the water properly

A sand filter not filtering the pool properly, ie. dirt and debris flowing back into the pool even after you’ve just backwashed the pool can be caused by a number of things. Let’s see what those reasons are and how to fix them shall we?

Old and worn out sand

When was the last time you changed the sand in your filter? If the answer is around 5 years then it’s time to change the sand. See Mr Pool Man’s guide on how to change pool filter sand.


Water will always take the path of least resistance. Channeling means that the water has created a channel in your media and instead of filtering the water through the sand, it just passes through, creating its own path. Channeling is a sign that your pool pump is too large for your filter. If you have a variable speed or ECO pump, try filtering the pool on the low or ECO setting to see if that works. If you don’t have a variable speed pool pump, then the only way to fix this is either to get a smaller pump (not recommended), or to get a larger filter.

Calcified Sand

This is usually caused by high pH levels in your pool, turning your sand into something like cement. The only way to fix this problem is to replace your sand media. To prevent this, always keep your pH levels where they’re supposed to be.

Mudballing or Gunking up

If you have just replaced your filter media sand and backwashing doesn’t seem to help with the filtering power, then you may have a mudball problem in your sand filter. This is caused by excess oils, hair, and other stuff that have clumped together making some sort of gunky mess inside that backwashing can’t dislodge. The way to fix this is to treat your filter media with some filter cleaning solution.

  • There are two ways to do this. If your multiport has unions, you can simply pop it off, pour in the filter cleaning solution and let it stand for a couple of hours. After that, you can backwash the filter for a couple of minutes, rinse for a minute or two and your filter media should be as good as new!
  • If your sand filter is hard plumbed into the pipes, then you can also apply the filter cleaning solution to your pump’s basket. Add the solution directly to your pump basket, turn it on, let it run for a few seconds, once all of the solution has been sucked into the sand filter then turn it off, let it stand for a couple of hours and then do the backwashing and rinse cycles.

Sand Filter Pressure problems

Now if the pressure gauge on your sand filter is acting up or showing high or low pressure where it shouldn’t be, then you may have a number of possible problems. This is not exclusive to sand filters and we have written an extensive guide on diagnosing and troubleshooting filter pressure problems here.

Leaky Sand Filter

The last problem you may encounter is the easiest one to fix, because it’s unfixable. If your sand filter has cracks on the body, then replace the whole unit. We’ll never recommend patching up a sand filter crack because it’s extremely dangerous and may cause an explosion. Remember that sand filters are pressurised vessels and they’re designed to hold high amounts of pressure. No amount of duct tape or patchwork can safely repair a damaged sand filter body.

SEE ALSO: What is the difference between sand filters and cartridge filters?

Sand Filter Recommendation

If you need to replace your sand filter, then we highly recommend the Water TechniX Sand Filter Aspire! It is currently the best selling pool sand filter on our online shop due to the fact that it offers the best value for your money! It has all of the features that one looks for in sand filters and it’s backed by Mr Pool Man’s bulletproof 10 year tank warranty and a 3 year warranty on both the multiport valve and gauge. Not only that, but it’s also at least a hundred bucks cheaper than comparable sand filters from other brands! Talk about value!

Here's our pool Guru Tom with a little bit more information about the Water TechniX Sand Filter Aspire.


Whenever you spot any of the pool sand filter problems listed above, it’s best to try and resolve it immediately as they don’t really resolve by themselves. In fact, the longer you let sand filter problems continue, the more likely it will worsen or even cause damage not only to your sand filter, but to your other pool equipment as well!

Now if your filter repair needs parts and your sand filter doesn’t filter the water properly anymore, don’t stop circulating your water! Just set your multiport to bypass/recirculate so you don’t get even more problems associated with stagnant pool water.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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