Have you considered dosing vinegar? Yes vinegar.
Apart from nitrate reduction, the use of vinegar improves the water quality of your tank in many other ways.
reduces nitrate
reduces phosphate
reduces cyanobacterial growth
reduces dissolved and suspended organics
The most recent article in Reefkeeping by Dr. Randy Holmes-Farley, an expert in water chemistry in our hobby for years.
http://reefkeeping.com/joomla/index....arine-aquarium
Why waste your money on over priced chemicals that many times negatively effect an otherwise great tank when you can save the money and buy beautiful fish like tangs, and corals?