Thank you for your help everyone. Lija, thank you for informing me about M. Marinum as I was unaware and have had not seen any information about it when searching. The fish tank has not been used in 2 years by fish or by other animals in fact and has been washed with a diluted bleach solution twice, 2 years ago after purchase and a few days ago. It has been sitting in my garage empty and I'm hoping that there is no sign of M. Marinum left.
Paul, the 40 gallon I have is the same footprint as a 55 gallon meaning it is 48" in length, however, that also means it is only 13" in width. This to my understanding meant 2 48" t8's running the length would be enough to light it. I was also not too familiar with plexi glass and didn't know it would bow even with a support in the middle of the aquarium. I just found someone locally giving a piece of plate glass exactly the length I need for free, how lucky am I?
Carlos, the current light tubes I have purchased max out at 6,500 so it seems that I have finally done something right haha. Thank you for your information on the glass and as I said to Paul I have just found a nice sheet the right size for free in my area! I will be contacting the person later today to acquire the glass.