Adhering Rock work to glass

[kfries]

I have decided that I need to add a small rock struture to my tank. I have an area on the overflow box that could really use some corals, but I want to build a rock wall along the overflow box to mount the corals. I am planning to build the structure about 3/4 of the way up the overflow. Does anyone have any suggestions on how I might secure the rock work to the overflow box under water? Can I use a silicone?

 

[docscorals]

I have decided that I need to add a small rock struture to my tank. I have an area on the overflow box that could really use some corals, but I want to build a rock wall along the overflow box to mount the corals. I am planning to build the structure about 3/4 of the way up the overflow. Does anyone have any suggestions on how I might secure the rock work to the overflow box under water? Can I use a silicone?

Reef Rookies has a great video about this on YouTube, although I don’t think it will work unless you drain the water low enough for a period of time. I think the silicone needs to dry before being submerged.

There are some magnetic options, but it may not work on your overflow. Not sure if the external magnets are sealed as well as the internal magnets.

 

[UncommonSense]

Silicone does work, you just need to be pragmatic about bead size, and wait for it to cure before submerging!

To explain:

— standard aquarium silicone adhesive is a Room Temperature Vulcanizing (RTV) formula, which means it cures at room temp, via exposure to atmospheric humidity! If you make the blobs of silicone holding the rock too large (<3/4”-1” diameter), you’ll ends up having to wait weeks for it to cure!

— RTV silicone typically has petroleum distillates in the formula, in addition to acetic acid… these off-gas over time as the silicone hardens (cures)… you want the silicone to be fully cured before you submerge it, which ideally will be 1-3 weeks after silicone application (depending on how much silicone is used/blob size)!


As an alternative, you could always silicone a bracket shaped piece(s) of glass or acrylic to the overflow box, then use the likes of 3/8”-1/2” acrylic rod like a nail to hold your rock structure to this bracket! (This would be best-bet if using live rock for the structure, as it avoids the part where the rock sits dry for >=1 week straight!)