Woohoo! Thank you thank you thankyou.....
Yes, water comes in at the right, exits in the left compartment. The sand is still, but there is now a "foam" at the top. I removed the basket a couple of days ago as I felt the filter media I was using to keep the splash down was just a nitrate factory. It now has 2 indentions in the sand/macromedia where the hoses are, the rest is still, but the top has that bubbly stuff. Now the bubbles are not down low at all, where the water pump is, and it goes back into the tank is clear and still. So I dont think I will need the baffle there. But it does mean that I can add more water.!
I will do the " shut it off and see where the water level ends up" thing in the morning.
Thanks again for all the help