Some ornaments can be very large and/or have a lot of small crannies in them that are difficult to completely seal. to address this problem:
I have often taken the cheaper small gravel (aquarium gravel left over from other projects) and filled the ornament. Then I pour food quality wax (used for canning and such) in to seal all the gravel in place and fill all the spaces. When this is completely cool (it melts at a low temp), I seal the very top of each with the aquarium sealant to make a final seal. It would be fine to leave just the wax, but I always feel that it is better to do a permanant job. It is much cheaper and easier than using 100% sealant - it flows well, fills completely, and is non-toxic and easy to use. I found a 10 pound block of it that was "chipped" and sold for about $1.00. It was a find.
Check to make sure that you have filled all the little holes at the top of the ornament with a dab of sealant ahead of time, so the wax cannot flow out. It rarely does, but could, potentially. Any that is spilled is easy to rub or scrape away, anyway.
You will have a solid ornament that will stay on the bottom of the tank, the filler is non-toxic and much cheaper and easier to use than 100% aquarium sealant. |