i just bought some at hobby town USA today, lows does not carry it as i checked there as well as home depot. its alittle pricy but its the right stuff to use.
I keep hearing about "great stuff" breaking down, but I haven't seen any issues in my tank. Some of the stuff from my previous tank is in my sump and I can't pull it apart. I never coated it in epoxy either. Out of curiosity I cut a blob of it open out of my sump and it was full of critters. I suspect to some extent it can function at live rock over time.
As for strength. This arch is over 4' long and hasn't had trouble yet... took 2 of us to put it in the tank.
I just started a full back wall for my replacement 240 and got the becketts pond foam just from what I had heard but it also says will break down with uv rays but with epoxy and sand I think I will expire before it does. not to mention it seems I rebuild the tank for some reason every 3-5 years or so. I am not to good with build threads as I am busy and dont really keep up but I will try to post some here and there of progress.
do you guys have any updates on pics of your tanks? this is really intersting to me and i am thinking of doing some things like this for my new tank i am building.
My advice would be to go far more wild than you think you need. Overhangs, arches, nooks and crannies. I used eggcrate as a base, than zip ties and other things to get everything in place... then spray foamed the heck out of everything and cut the excess off with a kitchen knife.
a little outdated of a pic, but you get the idea..
the arch on the left is over 4' long and nothing but a little spray foam and some eggcrate
Are you guys just using dead "live rock," or is it some other type of stone? I hear that tufa stone is good to use, as well as some lava rock. Would sandstone work? Is there a list of optimal stone to use?