I personally think StephenRC45 has the best setup:

4 x 20mm holes in the front slope of the lid, with duct tape stuck to the top of the lid for covering 2 of them when it's a little extra nippy!

Jet to suit average temps (i.e. high teens/very low 20's for summer) and when needed, pop the tank off and cover 2 holes to richen it up a tad!

Just my opinion though.
_________________
Andy.
NSR-WORLD.COM

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