i think even 4 of them wouldn't be enough light, unless you are growing low light plants. i have yet to see high light tank setup with these fixture.I'm starting up a new 125g (72in long x 18in wide x 24in high) and going all out on it. C02, RO/DI topoff, dosing everything, organic topsoil substrate, and I'm going to try and include some red plants. Probably going to be heavily planted dutch style planting. Height of the tank is 24in, and substrate is going to be 6in high.
I've decided I'd like to hang 36" Finnex Planted+ 24/7 LEDs. The only question I have, is if 2 side-by-side will be enough? Do I need 4? How high should I hang them from the top of the tank?