used it for years, no leaching, no problem other than the mess it leaves on your rocks if you need to move the coral. I say avoid it for looks simply because buying superglue gel is better if you know how to use it. I hope someone has talked about this somewhere before if not I can make a thread all about the difference in adhesives. But anyway its how you use the superglue gel that makes it better in my experience and opinion for both looks and convenience.
"
In general, cyanoacrylate is an acrylicresin that rapidly polymerises in the presence of water (specifically hydroxide ions), forming long, strong chains, joining the bonded surfaces together. Because the presence of moisture causes the glue to set, exposure to normal levels of humidity in the air causes a thin skin to start to form within seconds, which very greatly slows the reaction. Because of this cyanoacrylate is applied thinly, to ensure that the reaction proceeds rapidly and a strong bond is formed within a reasonable time."
In other words super glue gel or
cyanoacrylate is a fast acting glue when exposed to water, however if you don't twist and turn the coral a little while trying to adhere it to a rock it will set up crappy and unstable and fall. The twisting and turning allows the outer "shell" of polycarbons to be broken forcing the chain in alternate directions (making the glue adhere super fast when underwater). So glob that superglue gel, I get mine from the dollar tree, on the coral or frag plug then twist away until you feel a pull, next half a turn and you wont be moving that coral unless you want to.
just my long winded explanation and opinion hope it helped even if it was a bit off topic.
