Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Fresh water and salt water equipment are very similar in many ways, and most can be used for both purposes. (Just rinse the salt out really well. The trace that remains after a thorough cleaning is not a problem in most fresh water set ups.)
A few things are different:
1) A sump on a planted tank with pressurized CO2 may allow too much CO2 to leave. Tom Barr's solution is to cover the sump, perhaps with plastic sheeting, and duct tape it so there is the least air exchange.
2) Do not use a protein skimmer in fresh.
3) Lighting is indeed different. Reef lighting replicates the tropical sun pouring down into the water with no shade in sight. It copies the filtering that happens as the light passes through the water, so tends to be high in the blues. The ocean is fairly deep with respect to the light, and most of the red is filtered out. Fresh water lighting is more like the filtered light that trickles through the rain forest trees, and may be full sun only briefly as it reaches between the trees and hits the river. On the other hand, this water is often quite shallow, so a lot more reds pass through to reach the plants.