I may be wrong, but I'm beginning to think the marks on the glass are caused by snails or something similar. Mine are all spherical in shape and uniform in size.
yup, identical to mine Joe. They are about the size of a 5p coin and are all over the rear and sides of the tank. Cleaning just doesn't seem to remove the marks.
Aha! i done it i think, i cant feel or seel the suction from the filter bit inside the tank but waters spraying out the spray bar, does this mean its working?
erm i think so, on mine i kept pulling that starter thing to get all the air out and after it staretd getting hard to pull up and down ... then i turned it on and my spray bar was shooting out a continual stream of water.
i also went and quickly checked wether i could feel the suction on my intake .... but its too minimal to notice it actually sucking in the water!