What is meant when you say vacuum out to waste?

Answer 1

Some filter systems, especially sand filters, have a valve that allows you to exhaust the dirty water outside of the pool rather than return it back into the pool. For example, when cleaning their filter, many filter manufacturers instruct you to backflush to waste, meaning that you aren't supposed to return the dirty water to the pool but instead dispose of it outside the pool. Some other filter systems, like cartridges, do not always have this valve option. However, it is handy, regardless of which filter system you might have. There are always times when you might want to use your pump to dispose of some water (like when you're vacuuming out the really green guck on the bottom of a pool with algae). Hope this helps...

Answer 2

Every pool filter has an intake port and 2 output ports. One output port returns water to the pool; the other output port releases the water out onto the ground (or if a hose is attached to that port the water can be durected anywhere away from the pool. This output port is used to either remove excess water from the pool or to remove extremely dirty water from the pool while it is being vacuumed.