Well, we had thought of that... but since the tank is a 15 long... it is only about 12" deep + substrate.
so.... even though there is around 4wpg given the depth and the price I got the clam at I thought we could try it and if we noticed problems let someone with better lights have it....
BUT ... thanks for the information... I always want to know things I'm doing wrong-- =) , but i did know that we were pushing it this time!!! lol
Thanks!