I first tired to use DWC as my preferred grow method, and quickly changed over to drip. My air stones would clog constantly from the organic nutes i was using, my drippers started to do the same thing but hey were easier to clean, and if i stayed on top of it they never clogged. Like u said, take the air stones off and see how much is air is making it through the lines, your problem may be the air stones and not the pumps. Since your running a long air line u may want to get a strong pump either way, and use bigger air stones.
JackdaWack Reviewed by JackdaWack on . DWC Pump Problems Ok so I have 8 rubbermaids (2 gal or so) with 1 plant in each. I have 4 duel outlet pumps I picked up at walmart however the airline hose to some is fairly long and barely any bubbles come out after a few days of running. They say the output is 2.5 psi. I am aware that shorter hose length is a possible solution but I don't really have the option of haivng the pumps inside the area due to having nowhere to elevate them over the water level and no power source to plug em. So I guess my Rating: 5