That's a good amount of light for practically anything I can think of.
Have you considered getting 14K halides instead?
Your tank will be VERY blue with 20K AND those actinics.
The 14K will be whiter and the actinics will balance some of that out.
The coloration is purely preference. Make sure to look at several different color temperatures before buying.
I got the 14K Hamiltons and chose not to get actinics because they bother my eyes. I'm really happy with the purity of the lights.
Of course, if you get tired of the color, you can just buy a new color of bulbs when you change them out in 12 to 18 months. Changing the coloration does not usually affect the ballast or housing.
Have fun.