for a relatively small tank like a 20-gallon, you need
7 watt/gallon for high light plants and 3 to 4 watt/gallon
for medium light plants

"Phil Williamson" wrote in message
...
I have a 20 gallon tank with a few live plants in it now that are growing
slowly since I only have 15watts of lighting on the tank.. How much would
i
need to get my plants to grow at a reasonable rate? Also, is it worth
building a DIY light system or is it just best to buy a new hood and duel
light stripe?

Phil..