advice on lighting, used mh or t5 glo

[Navarchus]

In my experience to get a good cover when using MH to main factors to be considered:
Length of the tank and height (if it is a very wide tank then you should re-consider)

I would recommend a MH bulb for every 24 in! If you have 50inch tank you should use 2 bulbs, one for every 24inch and so on.

To select the power of the bulb I would recommend:

For a tank up to 24inch heights a 150 will do the job.
For a tank up to 30inch heights a 250 will do the job.
For a tank above 30inch height a 400 in needed.