Jimbo - Give Chris at Nanotuners.com a call. They have a bunch of different chillers designed specifically for nanos. He's a great guy to get ideas from... and tell him I sent you. I'm sure he can give you his suggestion of which one would be best for your situation. I bought my custom 24g Nano Cube from them too, so they drilled the 2 holes above the hinges slightly larger to be able to run 1/2" tubing to the chiller. The tubing hooks directly up to the chiller without any extra fittings. I'm going to have the 144 GPH Rio pump located in the first chamber send the water out to the chiller. On the way back to the tank, I'm going to use a barbed Tee so I can tap into the loop with my Auto Top Off System. This allows me to have only 1 return running into the tank as opposed to 2 (1 from the ATO & 1 from the chiller). Obviously, I will have to use a check-valve here to prevent water from pumping down into my fresh water reserve since water will be continuously running through the loop. My house stays air-conditioned during the summer months, but my custom Nano Cube included a 2 x 70w MH + 2 x 18w Actinic PC hood, so I've got 176w running during "the heat of the day" over my little tank. I hope this helps... Dave