Skimmer overflow

[FishyFishy!]

To be honest... Buy a new skimmer. Those things are terrible. My buddy bought one thinking it's great to save money... it never worked well for a single day that he owned it.

If the cup is overflowing, this is most likely due to water quality, a new skimmer break in, or the flow of water/bubbles needs to be turned down. If you say the valves are all open, adjust the water level adjustment on the skimmer (lower).