I assume you pics are the ones from the iPad? If so, I need bigger pics to be sure, but I believe that your cartridges are shot. Notice how the pleats are clumped together? That turns 10 pleats into 1; your EFFECTIVE filter square footage may be 1/5 of the original value!

Do NOT put the new cartridges in, till the goo is gone. (Cloudy is OK, goo-ey is not.)

The System3 cartridge filter is very badly designed in my opinion. They can work very well in arid areas with year-round pool operation -- no leaves, no thunderstorm debris, and no swamps. But if you let them get dirty, the force of the water trying to push through the filters will collapse the pleats as yours has done.

This is VERY common with System3 cartridges, so:

1. Be careful to keep the flow rate BELOW the maximum.
2. NEVER let the pressure increase more than 5 psi above the 'clean' pressure.
3. Always vacuum sludge with your OLD cartridges.

A single episode of a 10 or 15 psi filter pressure increase can ruin $400+ worth of cartridges.

Some folks here, who have them in S. Calif or Arizona love them. I utterly despise the things; I think they are hands down the WORST general use filter on the market. I suppose they'd be OK if they were ONLY sold in markets where they could work well, and with adequate warnings about correct usage.