[RocketEngineer]

Ok, While I feel this would work, there are a number of variables that will determine how well it works so lets simplify this:

1) the system works on differenetial pressure. When the ball is seated, the water under the ball and the water above the ball are both pulling the ball into the bulkhead. When the setup is initally started it will be just air under the ball.

2) The smaller, middle float is strong enough to lift the ball but isn't strong enough to overcome the differential pressure on the ball when its on the bulkhead. So, when this thing starts to fill, the length of the line between the ball and the middle float is critical because if it is too short the pressure difference won't be enough to resist the pull from the float and you will just get a small drain equal to what you are pumping in. Make it too long and the system won't produce enough surge.

3) So, the upper float provides the pull needed to pick the ball up off the bulkhead against the differential pressure. Since this one is on a longer lead, once it has triggered the ball to rise, the ball no longer requires that extra pull since the first float can hold the ball up.

This design uses the same concepts as a toilet flushing except that the flapper/ball is allowed to seat back onto the bulkhead before the tank drains. This is useful for saltwater aquariums because it means there isn't a rush of air before the surge causing microbubble problems. However, this design requires some tweeking and has several moving parts and potential failure modes. Adjusting the pull lines between the floats and the ball will determine the length of the surge. Adjusting how fast the water flows into the surge tank will determine how often the surge goes.

I would make one significan design change that I feel will allow this system to work better: Allow the ball to rise totally to the surface. You have the ball limited in how far it will move once the system is triggered but if you let the middle float go all the way to the surface you will remove the risk of too short a surge. Once you get it set up you can add a stop if you want but initally I would just use the length of line between the middle float and the ball to set how high the ball moves.

RocketEngineer