The 6 JBJ nano has a full hood, so clip on fans won't work. Did you have this tank last summer and it was fine temp wise? Do you still have the stock pump in there? Those things run hot and we change them out every time.... I think I have 6 JBJs (or more) and have had all the different sizes and all the different lighting (PCs, HQI, LED) The fans in the hood is not doing anything for the tank, it's cooling the lights and/or heat sink. They blow directly into the lid and never hit the tank itself. Everyone knows the "ahhhhh, how nice" moment when you hook up an ATO. Hooking up a chiller is just like that. I think you could take all my equipment, but leave me my chiller. It's a beautiful beautiful thing.