just a quick note, smooth rocks are key, sharp pointy rocks can and will crack the glass! I use a thin layer of sand in my vivs so there's a buffer under the rocks in my glass vivs. wooden or otherwise constructed vivs i wouldn't worry about.
and be careful heating a wet rock over 212 degrees they can and do explode if trapped water expands inside them! i usually set my oven to 200. that way it doesn't get tooo hot.
:!: :shock: dont take that quite so literally, remember that weight in water is displace over the entire surface area of the 4 sides and the bottom of the tank. so there is actually less pressure on any given point on the tank. not like with rock where the pressure is concentrated on to one or a few points. so the analogy that you can have 8lbs. for every gallon that your tank is rated doesn't exactly apply :? . but glass is very strong, and you should be okay.
however, in response to another post where it sounded like they had their tank on a stand w/o a flat surface completely underneath, i would advise them to find a better stand or place wood underneath the tank. but maybe i read that wrong, hehe. :dontknow:
after soaking the rocks to clean, you want to let them dry for an hour or two prior to baking them. Setting the oven at 275 is not a problem then, plus, you only need to heat the rocks long enough to reach 145 to 165 degrees, at these temps, all parasites, mites, etc will die. It's not necessary for the rocks temp to go higher. This takes approx 1/2 hour for a dry rock. I don't think that water will expand in heat, it will actually evaporate as the rock increases in temp, the rock itself heated to over 250 or 275 internal temp may weaken, but that would also depend on the type of rock, and it may shatter, but again, it's not necessary for the rock to reach those temps, and wouldn't be due to water content in the rock.