Sunday, June 17, 2012

How to clean a Sta-rite System 3 cartridge filter

How to clean a Sta-Rite System 3 cartridge filter

The following is a how-to guide on cleaning a Sta-Rite System 3 SM (S8M150 and S8M500 specifically  series cartridge filter. What makes the Sta-Rite System 3 cartridge filter system unique is the eight clamp assemblies that hold the filter together. Most full sized pool filters have a single metal band to hold the top and bottom halves.
This filter system has 2 large cartridges inside that are held together with eight screws in side clamps. (The  Sta-Rite System 3 SMD is almost the same except it has one large cartridge)
From start to finish, this takes about an hour.

Click on any image to see a larger version.

Note: A pool filter operates under a tremendous amount of pressure and could cause fatal injuries if the system came on while the lid was loose. Wine Country Pools & Supplies is not responsible for any damaged caused from the use of this guide. If you are unsure about turning off your system pump or any part in this guide, hire a professional to clean your filter.

What you will need to clean this filter:
-  A garden hose with water pressure.

What you may need:
- A filter tank O-ring (if the lid won’t fit or if the system leaks water from its midsection while the pump is on)

- A filter lubricant for the O-ring gasket
- A flat head screw driver

Turn off the breaker to the pump so there is no chance the system will turn on while cleaning.

Open the air release valve at the top of the filter to start relieving pressure.

Opening the filter lid:
Each of the clamp assemblies will need to be completely removed.

Start by unscrewing one of the eight round plastic knobs. Once the screw is sticking out about an inch, the large rectangle case of the assembly can be pulled back.

A flat head screw driver might be needed to pry this off.

Now pull the assembly up and off.

(It is also possible to completely remove the screw knob and then pry the assembly cover off alone.)

Note: There is a washer inside the assembly cover that can get jammed. Use the flat head screw driver to push the washer out and away from the filters center to free it.

Remove all eight clamp assemblies.
Lift the filter lid straight up and off the filter.

Removing and cleaning the cartridges:

Inside are two large cartridges. Pull the center cartridge straight up and out of the filter.

Now pull the larger outer cartridge up and out of the filter.

Use a garden hose to rinse off each cartridge, cleaning both the inside and outside of each. The goal is to clean off not only dirt but also any debris that has gottem stuck in between the folds of the cartridges.

Note: The better these are cleaned, the longer they will go before they will need to be cleaned again.

Note: If there are any cracks in the cartridge molds or tears in the cartridge fabric, the cartridge will need to be replaced.

Cleaning the inside of the filter tank:
To clean the inside of the lower tank, first remove the drain plug from the bottom of the filter.

Rinse the tank out with the garden hose, removing all dirt.

Also, take this time to clean the filter tank O-ring area as this can help reduce the chance for leaks and later help the lid to go back on smoothly.

Reattach the drain plug.

Reinserting the cartridges:
Place the larger cartridge in the filter first. Notice that there is an arrow on top of the cartridge that should line up with the direction of the in/out pipes of the filter.

Each cartridge has a single opening on the bottom that sits on an opening inside the filter and holds it in place.

Place the smaller cartridge inside while also lining up the top arrow with the direction of the in/out pipes of the filter and sitting it on its bottom connecting slot.

Closing the filter:
Place the filter lid back onto the bottom half of the filter. Notice the position of the pressure gauge and the direction it is facing. Twist the lid to get the gauge face to where it’s easiest for you to see.

Now, adjust the filter lid so that the top halves of each assembly line up with one of the bottom half’s assembly housing.

If the lid will not go down flush with the bottom half, the filter O-ring could have expanded. First, try some filter lubricant on the O-ring.

If the lid will still not go down, the O-ring will need to be replaced.

Reattach one of the assembly clamps. If you are unsure of how to place them over and on, use the following steps on each:
1) Remove the round plastic screw from the assembly housing.
2) Place the clamp bolt over the top and bottom connecting halves so that it sits on its own sticking out.
3) Push the assembly housing cover on over the top and bottom connecting halves with the screw in its middle section.
4) Now screw on the plastic handle to the center bolt in the middle of the assembly housing cover.

Attach a 2nd assembly clamp on the opposite side of the clamp you just set in place.

Attach the 3rd and 4th clamp assemblies in between the first and second but on opposite sides.

Attach the remaining four clamps in any order.
Once all eight are in, retighten each in a clock-wise direction starting from any clamp.

Restarting the filter:
With the top air relief valve still open, turn on the filter system (the pump). Once the system catches prime and blows out all of the air from inside, close the relief valve.

If the filter leaks water from its midsection, turn off the pump, tighten the clamp assemblies, and turn back on the pump. If the system still leaks, the filter O-ring could have shrank and will need to be replaced.

While the system is running, take note of filter pressure; this is the “clean” running pressure. When the pressure goes up more than 10 psi from this number, the filter should be cleaned again.

Note: The pressure can change when valves are moved on both the suction and the return sides of the pipes (i.e. pool mode, spa mode, spa fill and spa drain modes). Therefore, you should also take note of what “mode” your pool is in when recording its pressure.

Note: When the system is first turned on, it is common for some dirt to be blown in to the pool. This is from dirt that had gotten into the pipes during the removal of the cartridges or dirt that was dislodged but not remove from the cartridge during its cleaning.

Final notes:

There is no set amount of time that goes by when a filter needs to be opened and cleaned. However, a general rule is cleaning once or twice a year.
There are times when a filter will need to be cleaned even if it had been done recently.  A dirty filter can reduce water flow, hurting the filter’s ability to clean the water effectively. A dirty filter can also contain dead algae that will be used as food for new algae. 

Below are a few example situations of when a filter should be cleaned.
- After a major algae bloom in the pool.
- When the filter pressure goes up more than 10 psi from its clean running pressure.
- If you are not sure what the system clean running pressure is.
- If the pool water remains cloudy while the chemical levels are good.
- If the returning water to the pool from the filter system has visibly slowed.
- If the automatic pool cleaner has stopped moving and everything else has been checked (in relation to the pool cleaner)

If you are unsure, just clean the filter as a filter can never be to clean.


  1. You have described all the steps very well. Thank you for sharing it with us. Now I can clean Sta-Rite filter myself. Sta-rite is one of the best pool filtration systems that efficiently works and provides clean and hygienic pool water.

  2. Is there a tool that can be used to unloosen the 8 knobs

  3. Is there a tool that can be used to unloosen the 8 knobs

    1. Yes, its made by Multi Tork. It is an attachment that connects to a drill for quickly removing the filter knobs. I havnt seen one in years but if you try their website they might have details on getting one

  4. I have a question. I just cleaned my filters and reassembled my filter and I have leaking in the midsection. My o ring is only 2years old I retighten the clamps 4 times and still leaks I lubricated the o ring but to no avail. Do you have any solutions? Am I missing maybe be a washer in the clamps?