Clean cartridge causing too much pressure

[DMC83]

My pool is about 15' x 30' in ground concrete. I don't have the pump model, but i'm about to go outside and I will get it then and update. My pool is clear right now. If I leave the cartridge out; the pump runs perfectly and I could leave it all day. When I put the cartridge in that I just cleaned, however, the pressure and everything is good, but within 30min-2 hours; the pressure is right at 20 and the circulation is bad. I rinse this cartridge off with a garden hose attachment multiple times a day. When I pull it out; it's not even that dirty. I have a cartridge bath, and I have used dishwasher powder multiple times like I read somewhere to do. That didn't help. I used hydrochloric acid, because I read calcium can build up on the cartridge, that didn't help either. I just bought some TSP from home depot and I am about to try that now. I have a feeling that won't work either and I will still be puzzled. Any help is greatly appreciated. I just bought this cartridge not even 2 months ago, so it's still in good shape.

edit: pump is a Hayward SP2707X10un

 

[pooldv]

Welcome to TFP!

Please add your pool info to your signature so that we can better help you with your pool. More here, Pool School - Read This Before You Post

My first guess is that you have algae growing in your pool, nothing clogs a filter faster than algae. You can Perform the Overnight FC Loss Test (OCLT) to see if you have algae. Yes, it is very possible to have clear water and have algae growing.

What is your CYA level? What level do you maintain FC? How do you test your water? How do you chlorinate your water?

It isn't good to use muriatic acid on your cartridge before using TSP. You may need a new cartridge. I like Pleatco cartridges best.

More here in cleaning cartridges.
Pool School - Maintenance and Cleaning of Pool Filters

and here
Re: How to clean a cartridge filter

This is how we maintain pools, Pool School - ABCs of Pool Water Chemistry

 

[DMC83]

So tiny algae particles could be clogging it and I can't even see them? Sneaky buggers. I use test strips, but I don't really trust them. I compare the colors and only do something if they are out of the normal range. I see that I can't do that test with the strips. What kind of test equipment do you recommend? I chlorinate with tablets and I shock once a week with 1 gal of liquid shock from the pool store. I am trying to add a signature but it keeps saying "BB code font is not allowed." I have no idea what that is.

 

[Richard320]

Welcome!

What you're saying is that it starts out fine, then clogs up and restricts flow and pressure rises, and after cleaning, the pressure and flow are good again for another couple of hours. Is that correct? That is the way filters are supposed to work. The fact that you don't see piles of mud on the pleats doesn't mean it isn't loaded with microscopic stuff that is clogging the paper pores. It sounds to me like the filter is doing its job and the chemistry is out of whack. You've probably got an algae bloom going on and you're at a stalemate. You're killing and filtering out the dead algae, but more is growing to replace it. Hence the never-ending filter clogging. Dead bleached algae is going to look pretty close in color to the filter paper.

Post some test results and tell us where they came from and we'll see if something looks wrong. What we'd like to see is laid out here: Pool School - Read This BEFORE You Post

 

[DMC83]

Ok, i'm going to order one of the recommended test kits and then post the results here when I get them.

 

[pooldv]

Good plan on the test kit. I don't know what a BB code font is either.