Welcome to our forum.
for those of who dont know.... where can you get a scum bag?
Speaking of buying online, I clicked on one of the member's links and found a great site that i just purchased a pump that drains the spa in less than 3 hours completely for much less than the store near me. I can't remember the member, but it was Spadepot and they even threw in a cool magnet for the fridge that tells me all the proper levels as i reach for my milk each morning.
...but be sure to turn off the breaker, prior to removing your spa filters for cleaning, as we have removed many of many of these oil absorbing sponges from inside the pumps.
My dealer told me to use 1 1/2" corrugated tubing. I had a new 25' length around from when I was working on my sump pump. It drained my 400 Gallons in about 45 min. I turned my heater down, started the siphoning action from a jet (no air mixing) and turned off the tub at the breaker once the siphon took. It worked great!