What is the slimy build up on pool cartridge?

[Sassy68]

What is the slimy build up on pool cartridge?
I opened pool mid May and noticed the pressure was down from outlet.
I sprayed it off and soaked it over night in pine sol and dawn in a large garbage can.
Sprayed it off again. I plan to pick up a new cartridge this week but tried to clean it for the meantime. What is this stuff and how can I prevent it?

Chlorine and ph are always good. I have been using liquid chlorine and adjust ph with muriatic acid when needed. Also have robotic pool cleaner.

 

[needsajet]

Yeh it's probably time for a new cartridge unless the cleaning returns it to somewhat normal looking. It mostly just looks like it hasn't been cleaned regularly.

It's a combination of things... dust and dirt from the air, dead skin, body oils, sunscreen, hair, insect carcasses, possibly algae, etc., etc. everything that gets in the pool.

If you haven't done one for a while, do an Overnight Chlorine Loss Test

Cheers and welcome to TFP!