Trying to figure out my lighting....

[Eleni18]

So....this is my tank. 300 liters, 50 cm high with 8X39 T5 fixture about 20cm above water surface, so about 70 from sand bed. Live rock aquascape. I am trying to figure out how strong or weak this lighting is and what sort of corals would grow lets say on the sand bed, mid tank and around 40-45 cm from the lights.....No par meter....Thanks for any input

 

[cvrle1]

Only way to figure out how strong lights are with 100% certainty is using a PAR meter. You can rent one for a week from BRS for like $50.