Led education frustration

[lpsreefer]

For LEDs it's not some much watts per gallon per say. It's more the par level and spectrum. Also if you do go DIY for a fixture I would go wel modularled over radipled just for the fact that every thing is on prefabricated board so it's quick connect. No soldiering.
As for lenses depending on the depth of your tank they are for coverage/depth. As normal led with no lenses cover I think 120 degrees.
Bottom line for more info on what you need is tank size, and what you keep or planning to keep in the tank.