without anything to stop algae from growing, it WILL show up in your tank if you leave the light on 24/7. in my "dr seuss" tank, the one with way too much light and cow manure in the substrate, there is so much UV being pushed into the tank that it creates a hostile environment for cyano and some other types of algae(most types it seems). im trying to support a very diverse "ecosystem" in the 65g bluefin killifish tank, so i need the algae there, as well as all the plants. if i want as much life as i can get, i need to encourage the growth of producers(algae, cyano, plants) as much as i can, so i leave the lights on 24/7.
why do i leave the lights on 24/7 with fish in it? is that meant to imply that it has a negative impact on the fish? i cant say that it does. they seem happy enough to be breeding like mad. so far i havent seen any negative impacts.