Hey all. I have a octo classic 150 S laying around that I'm thinking of adding to the sump of my reefer 170. I would like to add a drain to the cup so I don't have to remove the cup every time just to drain it. Since there is no flat bottom to drill into I'm wondering if it would be possible to place a drain down low on the side of the cup. Since it's curved would I be able to get it to seal? I'm thinking maybe tapping and using a threaded fitting but thought I would seek advise before I damage the cup and render the skimmer useless.