LED lighting power for my tank

I have a 220g tank (6' X 2.5' X 2' tall) with arowana, pBass and some other fish. It is a planted tank.
I have been having very low lighting there (normal florescent lights T8 X 3 units). Still managed to get decent growth on the amazon plants. However, this is not adequate to see the colors of my fish. I need to switch to low cost LED.
I'm looking at the LED flood lights. I've attached a picture of what I'm looking at. Probably would use 2 or 3 units of these with 6500K range. My question is what would be the ideal total power of LED lighting for my tank size and depth? Is 100W total too much? These units will be simply kept on top of the glass lid.

any ideas please? I'm now looking at two 50W units of 6500K. Need to make a decision.

Thanks for the input guys. I'm going to go with this and see the result. Acutally I have one 20W 6000K LED flood light in my 65g tank which is doing good. I get good plant growth there too. Just not sure how effective it will be in my bigger tank. As people said, I can always add more if 2 X 50W is not enough.