quick question on air pump placement

all air pump instructions say to place air pump above the water level . is this necessary if your air lines enter your rez above the water level or can you put the pump on the floor in that case? +rep

They say that because if the power goes out the water can seep up the hose and drip into the pump and ruin it. You probably could get away with it being level with the stone or even slightly below it if the hoses are long or you might just end up needing a new pump.

You can use check valves on the airline and then its safe to put the pump below the level like the aquarium guys do.

the first time you turn off your air pump it will syphon back through the hose and drain your rez...

Actually, it's a capillary action that draws the water up. A cheap check valve will maintain air pressure in the line to prevent this and allow you to put the pump on the floor where the air is coolest. Another option is to use a larger sized hose than 1/4" then reduce it at the airstone. Or just skip it. I've had this happen in my fish tank before, but never in a DWC environment. I've turned off my air pumps countless times with the buckets full for one reason or another and nothing bad has ever happened. I don't use check valves on anything but the fish tank now... but hey, it's good, cheap insurance. Maybe I just talked myself into putting one back in line. =) Perhaps the water surface tension of fish tank water is higher(or would that be lower?), but I can't say for sure.

thanks guys