If you are feeling froggy you can always step up the pipe diameter you use just keep in mind trying to find a discharge hose for those larger diameters may take some searching and some cash. The only real limiting factors you are facing is compressor output in CFM and water depth. Also by using the PVC pipe if you feel you want to try and suck more up at once(Be careful not to overload the system as you will then get clogs) You could just use a 3' to 1 1/2' reducer on the bottom like a vacuum cleaner attachment. I don't know 100% the rules on posting links to 'Box Construction' stores so I'll send those on in the PM as well. Keep in mind going for max CFM's(Airlfow) here so bigger is usually better but no need to go overboard.

The air fittings you will have to choose yourself depending on what hoses you have for your current tank setup. The short story on what I'm thinking for your issue is probably going to be a 1 1/2' dia 6-8' section of PVC with two 90 degree fittings placed about 8' from the bottom to go through the side and then get the air heading back up the pipe (after reading this again that pipe diameter is to small for a double 90 turn see posts further on down for Rev.2 of the plan) going into say a 25' discharge hose that you can run up and over the bank or hopefully to someplace that the muck and water can go and drain and not go back into your pond. I am assuming your compressor you mentioned probably only has small hand tool air sized hoses as in 3/8' or so also any sort of regulator in line to reduce line pressure? You said you have a 2' trash pump so do you already own a water discharge hose?Īnyways I'll try and respond yet tonight and send you a PM with a shopping list and if I can a quick sketch-up using excel or paintbrush or something. I'll look into some possible cheap setups for around $50-$100 or so tonight using materials you can use on other projects if it doesn't work out. A trash pump can work I'm sure but you still would need to create either some sort of holding pool to let the sediment fall out of the water or a filtration system. I would stray away from using a water driven pump as it almost always has an impeller of some type and for suction purposes even muck/sand will start to mess with the internal bearing and seals leading to premature wear.

That water depth is going to be troublesome for a true airlift(However we have used them in as little as 4' of water but we use very large roto-screws like Ingersoll Rand 375 XP's: Which can put out around 300 to 400 something CFM).

Sandman mini hand dredge