Yes I believe flow is the most important thing both in high and low tech, there are tanks out there that seem to break the rules but I think it's widely accepted that flow is king and good flow will stop problems arising
Cover glasses on the sump and tank would help massively with evaporation also you with a bit planning on the stock side of the tank you may be able to lower the temp this will also help massively, also a cover glass on the tank will help cut light intensity so you may very well get away with 2...
This one of tims is also well worth a look and a great read
Blue jelly island :-) jelly berry pic page 5 | UK Aquatic Plant Society
And there is another one I came across recently but I cant find it now :( I think it was another of paulo's im pretty sure is was a 30l cube ?