They are schematically and functionally (in terms of light) very similar to the AI Hydra 26. They both have 2 pucks, containing 13 LEDs in each puck, spaced out a few inches. Somewhere in the 2-4 units should be about right on a standard 75 gallon, depending on what you are growing and if you are supplementing with T5.What size tank do you have them on?How many do they recommend on a 4 foot tank?
I do not have these lights.