All I was trying to emphasis was the fact that even though these LEDs don't project much heat into the water, they do require a heat sink and /or a fan to keep cool enough to run for long periods. Same with the drivers. And provisions should be made to make electrical connections safe from salt spray.
I don't want to change out my panels that often, so I try to keep the system cool. Don't want to compare credentials but my background has been in high temperature laser diodes that create a lot of heat and require massive heat sinks to last more than minutes. Keeping the devices cool will increase their efficiency as well as life span.
The advice to use commercial LED
mounting frames is right on the money.
We should move this to it's own topic as there is a lot more to discuss.