there is a chiller because i packed as much flow into the 30gal i could. most of the heat is coming from the pumps from what i can tell . i figured the mroe flow the better. i dont think any number of pumps can re create the flow of the ocean . so i did my best. as for your comment ( ..I guess come back in a month when its full of SPS..I wouldnt do it, but ok..) i dont understand , who speaks like that. you wouldent do what? anyway . i think it will be a great place for sps to thrive.