The main concern with tap water is very hot or very cold water wil kill any bacteria in the media and so will chlorine in the water (if your water supply has chlorine in it)
I have never ever bought a lighting system or tubes from a lfs. Always bought plain stuff from trade warehouses. Just as good and a fraction of the price.
They are more sensitive than some other fish (hatchetfish, not the marbled ones specifically) so conditions must be suitable, and good, for them. They are also scared very easily.
It was my pics you saw I think. They do get hot but not enough to melt the plastic guttering. I also line the guttering with aluminium to add reflection. It makes it even brighter
Using both is a good idea but I disagree with you saying UGFs need more work. I had a tank set up for over 5 years with just an UGF and never had to touch it. Canister filters need cleaning out.
I still need permission Alan. Can't print names without it. Some have PMd me to say what they don't want put in their details in the YB.
Thought it easier to ask who didn't first, so when I try to contact others I have fewer people to message