Pump or siphon

Shopvac Is a great idea, gotta make sure your cleaning it out or it will grow nasties, nutrient based solution in that filter in a warm dark spot = yuck. Super useful though. Siphon is a good option as well and I'd lean towards this one as I do not own a shopvac. Another option is to raise the bed up. then put it on an incline and install a port or plugs u can open and close. water will flow towards the lower bit and drain out when you need it. Really cheap option, use a towel to mop up the extra and ring it out in the sink. takes a while and is the messiest by far. One last option is to slide a empty tray under the full one to empty it. Good Luck!

Shopvac. Thats what i use to clear out my DWC reservoirs. I have those bases and I quickly realized that that is a design over sight on their part. They should have the fill screen on a hinge of some sort so you can flip it up and stick a hose down in there to suck it out. Because sometimes the wicking action won't link between the rope and the fabric and through to the soil. Then you have a gallon of solution sitting there doing nothing. Tip: If you go the shopvac route, make sure it's not a cheap metal chamber one. Grab a Rigid one from Home Depot. They are plastic and won't rust on you.

Yes, the Italian brand pumps Sicce got small pumps with a inlet filter and they suck from the bottom so you really empty every tray all the way. Use a simple timer clock to let them pump for the time that you want. I use them with my ebb and flow system for years now.