No woriies about the seaclone,
but no matter what mods you do to it, it will still be crap. Been there, done that.
That T that is on the output of the pump, before the ball valve, what the H^&L is that for? you should cap it if it isn't already. You can make a slide of some sorts to keep the water fall from being an issue from the crapclone(I had one also once.
). Additionally, not having a bubble trap before a return pump IMO is a bad move. You are witness to it. When the flow is slow, it isn't much of an issue, but when you flow much faster it is. Additionally, having the water just water fall into the return pump section is not good. Top it off higher if your backwash will allow. This will stop the waterfall from being an issue.
This is why I say there is more to a sump than just a box with some baffles in it. Not only getting the water to flow through it non-problematically, but also effectively. They don t have to be real complex, but there is some degree of thought that needs to go into it.