The don't. They have a hole in the drain cup with a removable rubber plug in it. You could fine some rigid tubing and glue it in or carefully tap the hole in the side of the cup and add a fitting. It's a metric sized hole too. You could likely take the cup to Lowes and find some PEX tubing in the plumbing section that would fit in the hole with some persuasion.
That said, unlike most skimmers, the BK Mini cups are very heavy and just sit on the skimmer. You need need to thread them off to get them off the skimmer. Just life which makes draining the cup pretty simple. That's what I do with the Mini 160 I have on my 100 gallon at this point.
I think you will love the skimmer. I have been constantly impressed with mine. It's the best performing little skimmer I've ever had my hands on. I had a brand new Aquamaxx Co1 that I bought for this tank and it was OK. I bought a used Mini 180 which turned out to be too large for the skimmer compartment on the 100. I then found a near new Mini 160 which I jumped on. It works amazingly well and has really impressed me.
I plan on ordering a Davy Jones Locker from Avast for the skimmate, and was wondering if it comes with a drain. If so, what size is the tubing? Thanks!
