Upon further inspection, I see that you've incorporated a clear view tube. I'm sure that you can figure out some way of using the fitting above using a short length of hose to the exit barb and then to a T adapter. Companies like General Hydroponics use a view/drain tube that's tinted blue to minimize algae but it's really not enough to prevent it. What I do is get a cheapo pool noodle from the $ store and cut it to be slightly shorter than the view tube. I then slide it over the tube to block the light and remove it to check the level and/or drain.