I'm upgrading my T8 lighting on Fluval Roma 90. The length of the tank is 60 cm, existing T8 bulb is I think about 46cm long. Are there T5 bulbs of the same 46cm size? Or if not what sizes does T5 bulb come in? I seem to be unable to find any info on any website that sells them and it is a real pain. I'm planning to buy this unit, to replace my T8's link: http://www.fish4aquatics.com/en-gb/dept_58.html I cannot actually start cycling my tank without light upgrade as I'm planning keeping HC cuba plant. Thanks for help!