I recently installed a aeration system, ECO7 pump, 3/4 inch pvc running 100 feet to water edge then weighted hose to three 9" diffusers. At 14 ft deep it will not work. Lifting it up a couple feet, works well. I assume this pump does not have enough push. The pond is down about 3-4 feet from full so when it does fill it will be running in 18 ft of water. Any recommendations on a pump for this application. I would really like to keep the diffusers in this location for the summer (close to center of pond and very near the deepest point). Any advice would be welcome. I would like to keep the cost down.
Or would results be the same if I mooved the diffusers into 10 ft of water even though the pond hopefully will fill to 18 ft
soon.
Thank you

I'm a noob and no expert, but I know that water will create 0.43 PSI per foot of depth, so at 10' I think you'll have to overcome 4.3 PSI to push air through. I'm looking at that pump for my own system right now, which shows a 5.1 PSI rating, not considering pressure loss through the length of the hose. You'd hit that pressure at 11.8 ft of water. I personally can't recommend a pump, but can guess that the EC07 is only going to push at depths not much beyond 10'. At 18' you're looking at at least 18x0.43 = 7.7PSI. Better scoot it to the shallow end for now! Good luck.