Hi Riggs,
I started in the world of marine fish keeping last September with an Orca 450 so here's some info on the tank;
Being a small water volume, the temperature can get high if the lights are on 'too long'. I had to limit mine to 8 hrs a day (10am - 6pm). Also, you'd be surprised how long it takes for the water temp to drop once the lights are turned off so the heat built up during the day by the lights is not totally lost during the night and so you get a slight increment in temperature everyday.
Wedging the lid open 10-20mm on both front corners allows a better air flow over the water and is a way of reducing your water temp if it gets too high.
My heater is set to 20 but the tank sits at 26-27 always.
Also, if the small mesh filters on the two pumps (suck into RHS rear chamber and return from LHS one - looking from the front) get clogged up then the pumps are having to work harder / are being restricted and they heat the water. The 'suck' pump is connected to the UV and skimmer so I use a long, thin artists brush to brush away the debris on the inlet filter. The return pump comes out easily since the vertical pipe to the spray bar is flexible and is easily disconnected from the elbow joint at the top - remove the inlet filter and clean.
The rear chambers can get full of all sorts of crud so I advise when you do your water changes to syphon the water out of the rear chambers to suck away all the crud. You can get a simple 'little princess / mermaid' plastic syphon from Pets at Home for £3 or you can buy the identical Bi-Orb one for £10 like me and get bugged by the fact every time you use it
. I also use a 12 inch turkey baster to agitate all the crud in the rear chambers so it's all floating around when you syphon it out. I used to have Nitrate readings of 20ppm until I started cleaning the rear chambers and now there always around 5ppm.
I closed off all but the top inlet into the RHS chamber and have a piece of filter wool behind the net. I clean the net and wool twice a week.
The spray bar will be stiff but will turn.
Finally, you need to mark your water level so you know how much has evaporated over time and hence how much to top off with RO water. The best looking way is to set your level just into the brown plastic tank rim so all you can see is water. As water evaporates the tank level drops into view and so you know when and how much to top off.
Have fun
they move very quick 
). An extra powerhead in the tank and maybe one attached to the spraybar to increase surface movement may help with the temp as well.
