I bought a pretty large acro that came attached to a rock, along with a nice sponge growing above it. I'd like to attach it as-is, to an existing structure in my aquascape. But with the way I want to mount it, it isn't balanced enough for superglue gel to hold. At least I've been unable to get it to stay. Is there some type of mortar or cement that would do the job, that would have adequate holding power if I applied it and held onto the rock for a few minutes? Or any other suggestions for this type of problem?