This is difficult to read.
To begin with, is the reason that the temp at the bottom of the tank is dropping due to the fact that you are running a hot tap somewhere & hence cold is feeding the bottom?
It also looks as though there may be setting problems or system fault given that you have to turn off the pump - you should not have to do that.
When you say "The solar pumps comes on at 8c about the bottom of the tank and is meant to go off at 4c above" do you mean that the pump switches on when panel temp is 8 dgrs > bottom of the tank & that the pump switches of when panel & bottom temps are within 4dgrs. If this is not happening then check the settings to begin with.