Hey Trevor,
Are both skimmers connected to the same suction line, instead of being plumbed seperately all the way back to the pump.
If thats the case, the 1st skimmer is most likely robbing the suction from the farthest one. Very common occurrence.
If you dont know if they are plumbed together in a "loop" fashion, you can check to see if thats the case by plugging the hole in the bottom of the first skimmer, and look at whats happening to the suction at the second one. It will likely increase noticeably
If indeed both skimmers are plumbed independetnly, they the length of the pipes and how many bends will rob the skimmer of skimming efficiency...
of course there is always the possibility it could be clogged somewhere.
Not long ago, someone else was experiencing something similar. As it turned out, a G.I. Joe was stuck in one of the 90 deg fittings where both skimmers combined right in front of the pump. hahaha.
anyways, hope this helps
