here are some of my experience hope it could help.
1. the size of your aquarium is important if you are planning to add co2 via yeast method. yeast method produces co2 at 2 bps max, if you are using the common yeast to sugar ratio, with 2-3 bottles of reactor running. if your tank is 10 gallons or smaller, then your co2 is fairly high level, but as the size of the tank increases the co2 level goes inversely.
2. there are different kinds of hair grass. you need to ask your supplier which hairgrass you got. the easiest hairgrass is E. acicularis
or dwarf hairgrass. this is one tough guy. in my previous set-up, which was infested by BGA, all my plants except dhg were not growing. some hairgrass as byron said are more difficult. but you need to observe your plants for a while, it probably is adjusting.
3. someone said that good flow,rich nutrient(macro and co2) are more essential than high light. so you don't have to worry much. as redchigh pointed out you can place your tank in place where it gets direct sunlight but you can't expose your tank to sunlight for long period of time. long sunlight exposure raises your tank temperature and may also cause imbalance, which may lead to algae breakout.( my tank receives direct sunlight for more or less an hour and my plants are doing well, i.e., my hygrophila polysperma green's tips are turning red, my crypts are flaming and my pearlweed sprouts new shoots 3 days after trimming.
4. lastly, you don't need much of an equipment in raising hairgrass and aquatic plants. all you need is luck and patience. i saw an all hairgrass set-up (~ 2.5 gallons) without co2, under direct sunlight that is thriving and even daphnias are living there. i just don't know if it is still running.
good luck and HPK