The Siphon Stoppers, as installed in my Planet Aquariums tank... so it's possible that they were mounted a bit high, who knows. Anyway, they caused micro bubbles, as the jets of water coming down the vent guides into the tank carried surface air with them. In a freshwater tank? Fine. In a salt tank? You're just asking for salt creep to cover everything in the vicinity.
CA recommended I turn the returns to an angle, to get them below surface. In my tank, I'd have had them at over 30 degrees, and it looked bad... no thanks.
I ended up cutting the guides off and closing up the vents with silicone, and drilling a new vent just below water level. Presto, no more bubbles. Works fine, I'm still using them.
Honestly, if I had to do it again, I'd just assemble my own returns from PVC and Loc-Line. I think I could come up with something a bit more compact that would work just as well.
I do always try and mention, when complaining about Siphon Stoppers, that the two H2Overflows I bought, from the same company, I am VERY happy with. Clean, quiet, easy to service, carry a ton of water, great surface skimming capabilities, compact... I really like them. I did not get their external overflow box... my implementation required something a bit different, so I have no opinion on that one, or their sumps. Love the idea of a modular, extendable sump system, and love the idea of injection molded polyethylene as a sump, but I have to admit... they don't look very good when compared to something from Trigger, or any of the other acrylic sump makers. Me? I'm using a converted 55g tank as a sump, so I guess I shouldn't be talking about what looks good
