Be VERY careful with that wood. I tried it once and it crashed a 55gal tank and took out about 2 dozen fish. The wood you are looking at is probably grape wood. It is normally fine by itself, but is known to grow mold/slime at first. It also floats. I assume that mine must have been treated cuz I don't think wood alone could of caused what I saw. Within 24 hours of adding a large piece the tank had 0 ammonia and 5.0 ppm nitrIte! My tank is densely planted and I could not believe the problems that log caused. In a 10 gallon bucket of water all by itself the log again produced 1.0 ppm Ammonia and 5.0 ppm nitrIte in 24 hours. It also clouded up the tank with a bacterial bloom. Half the fish got caught in the first spike. 5.0 ppm nitrite is brutal to fish, its basically a death sentence. The fish that I moved to other tanks only 24 hours after I added the log still died of nitrite poisoning over the coarse of a few months. My ember tetras are the only fish that actually survived and still currently alive from that incident. The log was in the tank for 48 hours during which the water was changed almost 300%(yes 300). If you do wish to try using this or any BOUGHTEN non-aquarium wood submerge it in a bucket for at least 48 hours and do a water test. Also pay attention to how it smells. I stick with aquarium wood or dead branches I collect from the woods, neither of which have given my any problems. The latter will break down within a year usually, which doesn't really matter in a densely planted tank.
