On those eductors, the vendor site said;
Water enters the Eductor through the nozzle creating water pressure that in turn develops a vacuum, drawing additional water into its body for increased circulation.
If I'm reading that right, it sounds like it's pulling in additional tank water to expell along with the pumped water. Is that right?
Also, If i put one on my main return, which is always underwater except when if shut down the pump to do a water change. Then, when I turn the pump back on, it's in air for a couple of minutes till the water level rises high enough to cover it again. In that case, would the eductor suck air? Or what?
Thanks!!!