In the past I used led flood lights like this https://encrypted-tbn3.gstatic.com/...b1dbUo9kkzVNkuYIWLLTuQqrpp9mb7CeAfPQ&usqp=CAc
I used 2 30w 6500k flood lights on my 75g which is 22" deep and they did great. They did go out after about a year though but that is because I later found out the ones I got were not the ip65 waterproof rating. Google or even search these forums. I'm sure you can find more in depth post about them. I paid something along the lines of 15-20 dollars for the 30w.
Maybe this video will help a bit. He does par test on several aquariums.