BIG MISTAKE.

[WhistlingBadger]

Sorry for your losses--I'm glad you could save some of them. It's a good warning to all of us to read the fine print before putting anything in our tanks. Thanks for sharing and good luck going forward.

 

[Lynnzer]

I took a good look around for rock glue stuff after my last expensive mistake and have found something that seems wonderful. Coralcrete by Seachem. I bought a stick of it and placed some between some new rocks. It says on the pack that it hardens in 15 mins. Mine was still pliable the next day. Ah ...... something wrong? You bet. It says nothing on the pack that the inside of the stick has the actual hardener which has to worked into the outside layer. So I did it again and it seems great. Non toxic and appears as solid as the rocks I'm putting together.
Recommended by me. I guess it's just as good on freshwater rocks and wood etc.

 

[davros]

You do have to knead putties to mix the components, they assumed we all knew? Odd thing to leave out.

 

[Lynnzer]

Well my last impression of coralcrete seemed OK, however the rock architecture all came apart while lifting it. It seemed perfectly stable when the stuff had dried out, and I left it to fully harden overnight. In fact a couple of overnights.
Back to the drawing board. While searching my cupboards for superglue gel I discovered my wife's old glue gun with lots of sticks.
Why not? Yeah, I just had to give it a go. And you know what? It's the best thing yet. The hot glue which isn't really glue as we know it, fell into place in the joining surfaces and small crevices where they are going to be hard to pull apart. Just to top off, I also glued the edges of the joins with superglue gel too.
The Bostick glue sticks for the glue gun aren't toxic so I think I've hit on the perfect answer. Section 14.5 of this will show non toxicity.
Time will tell of course but so far it's the best solution I know of.