Sealing tank decorations to keep out its toxicity

Just get a small spray bottle from woolies or bunnings, get some polyester resin from bunnings along catalyst and general purpose thinners.
Add thinners to resin at one quarter of the container you are mixing it up in, then add the catalyst., mix then add to throw away spray bottle then spray the drift wood or any in tank decorations that may leach tannins or toxins, really soak it every where.
I use a hair dryer to make the resin go off faster but in the sun works fine. The drift wood in now sealed and non toxic in anyway!
This works in saltwater and fresh on anything really that may leach or be toxic in some way!!
Oh and if you want it even more interesting, add a pigment of some kind, they come in all colours.
Use the thinners to clean the resin off you and the tools.