Can I replace the 55w bulbs with 36w bulbs? I have 3 x 55w ballast that run the 6 x bulbs. I have read on other posts that if I change the bulbs to 36w the ballast will run them just like 55w bulbs, that is the ballast will deliver 55w to the 36w bulbs.
You can run the smaller bulb but the coverage is going to be bad. If you have 3 ballasts, just unplug banks of lights until you are happier. If this is a 4" tank you could run 2 lamps for example.