PentekBP-420-1 Polypropylene 1 Micron, 4.5" x 20", 1 Count (Pack of 1), White

This thing really works. Had to make a connector to attach to returns on pool. For some reason I am only having to add tablets to keep chemicals balanced. Have only shocked once since putting these on…about 8 weeks in 95 degree days.

Had problems with pollen/silt in the bottom of my pool this year. Cartridge filter not able to filter out the smaller microns and I assumed it was blowing it all back into the pool. Attached DANMAR Directional Pool Skimmer Jet Return Nozzle and then cut off the end of this filter to attach to it. Had to rig it to hold with couple of zip ties (cut holes to thread zip tie for tight fit) and clamped the open part- It WORKED!!! I was worried it would build up too much pressure on my pump but didn't raise it much. By the time I finished vacuuming I could see that it was blowing the dirt directly back into my pool like i thought. This filter caught what was blowing back into pool. After vacuuming I disconnected the vacuum and let it run for an hour to catch anything I stirred up then removed it and put regular return eyeball back on. Checked an hour later and the pool was clean- nothing settled back to the bottom. Wish I had discovered this at the beginning of the season, but ready for next year! Well worth the money and will buy more! Very pleased!!

Good solid product

I put it on my pool and worked great! Only took about 3 days of stirring/ added chemicals the pool to go from green to clear. After everything cleared up i took it off and let the cartridge filter maintain.

I found another product that said it was an exact fit. It was not even close this Pentair bag filter, the real deal one micron fit the filter housing perfectly very cost-effective way to filter your water.

Doesn’t fit my 4.5 by 20 filter casing it just falls in can’t figure out how to get it to work and since the filter I was replacing didn’t need replaced for 6 months I can’t even send this back, it’s useless. I’m very disappointed.

I have a metal frame pool for my kids. I got behind on treatments and the Algae all of a sudden took off and I couldn't keep it under control. I decided to try this experiment. I got a wooden oar and created a whirlpool. It is approx 4500 gallons. I added 4 times the shock they suggest you add every week. I cut the top of the filter off and hose clamped it to my discharge line. I attached it to my pool ladder and covered the pool with the solar cover. I left for 3 days and came back to really clean water. I couldn't believe it. It appears the water level kept going up higher in the bag do to all the filtering. I bought a couple more and plan on using them on the cheap Venturi style pool vacuum I have. 3 days later and we are back in action!

I have a 18' Intex swimming pool that had a major attack of algae at the end of last season. I was thinking I was going to have to empty it. I then found these mentioned on a YouTube video, and decided to give it a try. Man, these guys are the real deal. The amount of junk it catches that the filter misses is phenomenal.They can be used by simply throwing them in the wash. I am thinking I will continue to use these throughout this season as it works better than the paper filters, and they are reusable. Inexpensive too.Thank you whoever makes these.If you have a dirty swimming pool, get these.