Surge idea with dual 3-way ball valves

[WhiteRat]

Bear with me guys, still no scanner.

 

I am trying to design some reversing surge-type flow near the top of my tank-to-be. I don't have a lot of room above the tank so I can't really use a dump-tank.

 

Please note that I have never used motorized three-way ball valves before. If what I'm suggesting is unreasonable, well...that's why I'm asking you folks who hopefully have more plumbing experience.

 

Valve A is on the pump intake, and Valve B is on the pump outflow. When both valves are in position 1, Valve A is connected to an intake on the left side of the tank and Valve B is connected to an outflow on the right side of the tank. When both valves are in position 2, Valve A is connected to an intake on the right side of the tank, and Valve B is connected to an outflow on the left side. This should create a back-and-forth surge as the pump spends (guessing here) five or six seconds pumping water right to left, then five or six seconds pumping water back left to right. Hopefully some bright engineering type can convey to me a means of keeping the two pumps rotating in synch, perhaps both being driven by one motor via pulleys/belt?

 

Options:

 

Intake and outflow entrances on each side are totally separated (perhaps one is below the other).

 

Intake and outflow entrances on each side are the same piping with the Y-valves just creating a criss-cross between the two. This worries me a bit.

 

Thoughts? Opinions? Malignant curses?

 

This isn't going into a nano, I'm trying to plan a big 150g, but I hope you all will bear with my queries.

 

Hmmmm. If I could find a reversible quiet, reliable, fluid pump then I could just make it all one big loop from left of tank to pump to right of tank, and just reverse the direction of the pump every several seconds...?

 

Thanks in advance for any thought at all,

 

Ratty

Ratty's Reef