How much water in sea strainers?
 

I have sea stainers and noticed last week I had one engine getting a bit warm. Open the hatch while running and noticed in both stainers the water was real foamy and not full of water, but a good stream.
Should they be "full" of water?
If not, lower my intakes?
Ideas?

With my engines running the water in my strainers is swirling around the sides quite violently from coming into the top, thru the screen and out the bottom. Actually looks quite empty. Shut them off and they are full up to sea water level. Normal? Thats sitting still.

I don't know what their doing at speed however. I'm sure they are filled more by the water being forced into them from the pickups?