help with remora 1200 skimmer

[Flash]

I got this about a month ago.. worked perfectly...but I came home last night and it's not skimming much of anything at all. The pump is going it's noisy, but the first chamber is almost dry, second chamber is bubbly but not enough to fill the tube to the upper container, and the third chamber is flowing normally. I can't figure out what is wrong.. I tried to adjust it for hours last night and still nothing. any ideas?