"Vacuum to Waste" - Separation tank

[new2poolschool]

I had an algae problem so I killed off the algae then followed up with a bottle of Sink and Sweep to clear up the water. I got a little ahead of myself. My multiport valve has a waste setting. But it appears to drain to a separation tank, not to an outlet. My question is: If I vacuum to waste, is the debris created by Sink and Sweep sufficiently large that it will be caught by the cloth bag in the separation tank? Or am I wasting my time vacuuming to waste?

I have a really old 72 sq ft DE filter. I've never backwashed or used the waste option on the multiport valve. I just change out the DE each time when it's time.

 

[Bama Rambler]

The separation tank is to catch the DE whenever you backwash. When you put the multiport in waste mode it also goes through the tank and it should either go to a drain pipe somewhere or just out on the ground. The bag should catch the stuff anyway.