Lovefornature-- I have two of the pp209 30oz glass feeders and I rarely fill them full . When you turn the feeder upside down the base fills and the glass level goes down. So when you see none or very little in the glass part the base is still full. The key for you should be the amount of useage and since you dont want to waste sugar water, if they are not using whats in the feeder in say 3 days, you should put less in. Only in past week have I been filling my big feeders full because they were draining them in a day when I only filled them half full, but that is changing now as migration is under way and many of my hummers have moved out and now there are just a few here, but I expect that to change from day to day as its not even august yet.

Thanks hummersteve, I was worried that the base was not getting full enough for them to get any sugar water. The sugar mixture did run down into the base, but I can not tell how much went in and was worried there was some suction issue. Hope that makes sense :-)

LFN-- Actually the hummers can tip you as to wether they are getting any nectar. Sometimes I have let a feeder go empty knowing I have others for them to use , if they stick their beak in only once and leave it and go to another feeder chances are it is empty or they are not getting any, but if they stick their beak in more than once they are getting nectar, hope that makes sense to you.