How many air stones? If you could add one or two that would help performance quite a bit. My skimmer came with the used set up I purchased a couple of years ago and I'm quite content with it's performance. I did a couple of mods to the original config. It came with two air stones and I didn't add any, but changed the t-fitting hookup into a small acrylic manifold. I've seen photos elsewhere of an air stone manifold made from a pvc end cap. Drill it, tap it and then you can attach multiple air stones to it. Can probably glue the fittings as well if you don't have tap & die handy. Here are a couple of shots of mine. I added a t-fitting at the output to enable easier draining if required, also a ball valve to control water column height as well as a slip union to allow easy adjustment of the output pipe length. It is an HOB DIY design but I built a separate stand because I didn't like the weight of it on the rim of my tank. There's an AquaClear 301 ph in a pre skimmer box pushing the water (8 watts) and a Stellar W60 air pump for bubble production (3.2 watts)
