Yea I was thinking about two 13 watts but they aren't water proof endcaps. Also I think a single 32 watt would be easier to retro and will add more light. I'm going to continue looking but haven't found anything yet. Drsfostersmith used to have them but I guess sold out of 32 watt and only have 65 watt. On sale too for 39.99, wish it would fit.