co2 tanks

[BCOrchidGuy]

That's a smoking deal from OA. The bubble counter is so you can control precisely how much CO2 is going into your tank. If this is for a planted tank the wet dry removes all the CO2 you add to your system so you're having to add more CO2 than you should. The CO2 should be injected into the intake of the return pump though so it doesn't just bubble out of solution before it's used the impellor of your return pump will break the CO2 bubbles into micro bubbles which will travel all through your aquarium. You're filter media functions best in a wet dry as it's designed, adding CO2 under the media would completely change the bacteria that grows in the media. I'm not sure that the media would be saturated with CO2 either, I'd tend to think it would just bubble up and out with out doing much. Do a google search on Steve Pushak's planted tank. He really goes into CO2 and everything else plus he's local he used to host most of the Vancouver plant club meetings.
As for cost, I don't think you can build your own for $134, that's a good deal.

Doug