Lead weights are not a problem. Given their half life they are not about to decay in your aquarium even if you do no water changes for the next 100 years and live to tell the tale.
peat in a test tube won't be that bright yellow. Even if there is a pale yellow to the tank.
The soln. turning shades of red is an indication of elevated Nitrate.
It looks good. I'd personally get 2 halides or T5 VHO if you are upgrading (or thinking of).
Everything seems healthy and the corals are happy, so if you are I'd just leave it.
Getting the moss looking like that is the easy part. Finding wood like that is the hard part. :tears:
I'd love to do it. Someone find me wood like that :lol:
Here's me making an educated guess based on how it works with other animals.
If you have a juvenile fish that is born and raised in a tank with a UV filter; it's immune system will be fine given its surroundings but considerably weaker as compared to a fish that was raised under normal circumstances. Most animals (humans included) inherit a certain amount of their immune from the parents (again - not sure how this works for egg laying species) and some of the immune develops within weeks to months to even years after birth.