I don't plan on having coral just live rock and anemone's.
i knew that employee was wrong! i shoulda just put the anemone in my fowlr anyways
all kidding aside, you will need stronger lighting than a double bright fixture if you plan on housing anemones.
instead of double-bright, id look at their reef capable fixtures
amazon has the 18-24" reef capable fixture for around $180.
specs are as follows-
# of white leds-18
white led wattage-1w
# of blue leds-3
blue led wattage-1w
total wattage w/ b+w on- about 21 watts.
lumens-1300
price- 180.93 with free shipping
and now a similarly priced and comparable TaoTronics fixture (on amazon)
# of white leds-27
white led wattage-3w
# of blue leds-28
blue led wattage-3w
total wattage w b+w on- about 120 watts
lumens- roughly 5500
price- $179.99 with free shipping
im sure that the Marineland fixtures are decent sets and for a given need they do fairly well, but as you can see, there are other choices out there that are roughly the same price yet offer so much more growing potential and flexibility ( marinelands come preprogrammed with a light schedule, TaoTronics B and W are on separate plugs, therefore allowing timers).
im sure that the Tao unit on a 20g will need to be dialed back but the nice part about it is that you have the light on hand if you decide to house higher-light corals or decide to upgrade to a bigger tank.