newbie sump idea take a look

i have a general idea on this sump using two rubbermaid tubs please comment on some advise or tips to make it better or if you see a fault or anything along with good external overflow ideas to keep siphon or to improve one to make it where it wont loose siphon thank you along with some good things to put in them

 

Put one above the other then connect with pvc so you don't have to worry about siphoning.

I do have a comment about your water change line... I don't think that will work the way you want it to because once your tank level drops below overflow box level it will start pulling from the sump and you won't be able to get enough water from the sump to do a large enough water change...

 

I don't think the first chamber is really necessary. It may just limit usable space in the sump. You may want to think about creating a section that is not effected by evaporation to house your skimmer. As skimmers are effected by fluctuations in the sump levels. This would also help in isolating the evaporation to 1 section of the sump to better control tank level.
this is done by putting baffles into the sump so that water flows up and over 1 then under another and so on.
Like this

 

thank you for the comments let me see if i can change it around a little an see what you think along with the siphon comment please explain a little thank you

 

new design for sump

i updated it tell me what you think and if it will work along with a good way for an overflow an pump, and tell me if there is any faults or ways to improve thank you very much please comment and the line that dumps water in will be underwater sorry messed up the drawing