We picked up a 30 gallon extra long to use as a frag tank. It's dimensions are 48" X 12" X 12". We plan on drilling it and building an overflow. We have a SCWD coming to use as a less expensive wave maker. Is it correct that alternating currents help the frags grow straighter?

What flow rate should we aim for?

Does anyone use substrate in their frag tanks, or is a bare bottom tank better?

And, lastly, will a dual T5 HO fixture be enough light for most corals, or should we get a quad fixture?

Any help will be greatly appreciated!