Just one tunze 6040 in my 40 gallon softy tank, seems enough for them.Water movement in a saltwater reef aquarium is important on so many levels so using the right powerheads in the right configuration for your tank is a pretty big deal! That being said there is not a "one size fits all" solution when it comes to the number of powerheads you need, which brands you use or where they should be placed. For the most part anyway. But it should still be interesting to see how many powerheads are members are using!
1. How many powerheads do you have in your saltwater aquarium? (what size tank do you have)
2. Which powerheads are you using?