The 55 watt bulbs aren't that common, but they are produced by a larger company, and cost far less. These are very cheap bulbs, and will burn down in only 6 months or less. For plants, don't bother with these. Buy the coralife light bulbs.born2lovefish;760633;760633 said:I have 4 65 ballasts. Two are going on my 75 gallon and 2 on my new 40 set up. Both tanks will have plants. Seems like 55 watt bulbs are more common, which is why I was wondering if I could use them.