The general guidelines is one (1) radion fixture per every 40 gallons. Each unit of Radion is able to cover an area of 24X24 inches.

When in night mode and running the LEDs below 10% its very difficult to control the current through the LEDs accurately, so due to different tolerances in the back voltage of the LEDs on different clusters, and the fact that the royal blue LEDs are on two different LED driver channels (one channel per cluster for royal blue), you may see one cluster turn on before the other at the lowest of intensities. Also due to the same tolerances, you might see some LEDs that might not turn on at the lowest intensities, which is why we demo the color while in the color selection window so that you can see what intensity works for your tank. - posted by EcoTech Marine FAQ

Clouds and Thunderstorms are random, and their probabilities of occurrence are based on the amount of time between data points in the artificial mode graph. i.e. there is a much lower chance of either of these occurring when there is only 30 min between data points than if there is 3 hours between data points. This is because if you had a 50% chance of a storm occurring during any length of time between data points, and then you had 24 different half hour segments throughout your day profile, you would end up seeing 12 thunderstorms per day every day which is not a very natural occurrence. Therefore during smaller time lengths where clouds or thunderstorms are enabled, you have a lower chance of actually seeing the storm or cloud occur. You can always force a thunderstorm to occur at any time by using the buttons on the top of the Radion. - posted by EcoTech Marine FAQ