I'd recommend a PAR bulb. You can stick with a "regular" bulb from Home Depot or opt for a refugium-specific PAR 30/38 from a vendor like Coral Compulsion.
My Kessil H150 Purple Spectrum is the best thing I've bought for my tank in a long time. Also for $68 shipped off eBay, I can't complain! Grows more Chaeto in a week than my old clip on light would grow in a month or 2. I can't say enough good stuff about the light!
Less than 10bucks a 100w or higher clear light bulb ge/Phillips and hd clap on light from home depot and ill give anyone or a ractor a run for there money when it come to growing macro ....there no is need for radions pro to grow cheato
i dont run a heater on my system and i also have chiller i run metal halides on my dt i know how to control my system u have look at ur set up to answer that question but as far as grown the greens thats how i grow it...... easy and simple
I've been looking into some led plant grow lights on ebay. There are a few regular screw socket bulbs that have 5 3w LEDs on the end which also give off a purple light. Trying to win the bidding ones at a low price rather than use the buy it now links for higher.:lol_large