my friend has a 55 gal. setup for about 3or4 yrs. needs new lights can he run just t5 light? what would survive and how many do you think he needs? current 54 watt. double fixture good. two of them? or 8 54 watt. fixture a little pricey. he now has very little in there I'm sure he would love to get some acropora but I told him he may need m.h. for that. what do you think?