[mike31154]

Each scenario has its pros & cons. Set ups with fans need the fans to work, or else. Set ups with large heatsinks & no fans are heavy & tend to be overbuilt to ensure there is sufficient mass for cooling without fans. You can also hybridize with a moderately sized heatsink and a couple of larger fans to move air over the heatsink. Not many people actually do the math as to how much heat each LED produces & what is required to sufficiently cool them based on the actual mass of the heatsink without fan. Some folks go as far as installing temperature sensors to control fans. That gets a little more involved & complex for the average DIYer. As far as the tube set up, a fan blows into one end of the tube & as the air moves along, each LED adds heat & the one(s) at the ends of the tube(s) will tend to benefit less from the air flow since that air is already heated up from the LEDs upstream. Works fine for a shorter run of tubing, but a long run could spell disaster for the LEDs at the end of the tube. All depends on your particular needs & preferences.