Did you ever get any advice? I clicked on your link and love the Mystic Grey next to it.

yeah, that makes sense re: closed circuit/air in the lines. regarding running the boiler, definitely.i have a wood stove in the house that runs 8/12 months of the year for sure - it's my primary heat source. i recently put a basement under the house and it's prepped for infloor heating, though i don't have it hooked up yet. there's a unit made by a company called "walltherm" that is certified for interior use and has a coil in it, so i don't need the outdoor boiler. it would be heating all domestic hot water as well. i will put in radiant heat in the greenhouse, but it was the hot tub that was the question.

Yes. Used it on a few jobs with no issues.

As a builder, I have personally installed this type of flooring. In the beginning, I used ti have to use a tapping block and or a small piece of the flooring (as instructed per the directions). Now, Duravana/LL Flooring has a tapping block specifically designed for installing Duravana flooring. The chipping on the edges is usually from poor installation. ALSO, I have noticed that every so often, a board will have excess lamination over hanging the edge. If you don't lightly sand that down and try to install it as is, it will chip. Duravana is a fragile product until it has been properly installed. Also, I have noticed in several photos that were posted that the boards are not even fastened together properly which tells me that it was installed improperly. As another contractor stated in the comments, read the directions. I install Duravana floors often and have had no issues. Stop watching HGTV and ask a pro.