Originally Posted by MarkA123
Ok mine has a brace but what do you mean by bow? Mines a bow front but I'm pretty sure that's not what you mean.
When the tank is full of water that water will put pressue on the glass. Water weighs in at just over 8lbs a gallon and that is a lot of pressure to be putting on the glass.
I don't know anything about older tanks and if they can hold the water without that middle brace, but the idea is to help support the glass from bowing out from the pressure because as the glass bows out, it will get weaker. My (and I'm sure other's) concern would be a catastrophic failure and all the water would come rushing out along with all the live stock.
If you are concidering using the tank without a brace then I would recommend at the minumum you fill the tank somewhere where if it does fail, you don't soak your house (like do it outside or in a garage or something). You can see the bowing by putting a straight piece of wood or a long straight edge along the side. Without water it should lay flat, see how far off it sits with water. If it doesn't bow at all, then you *MAY* be ok... if it bows even 1/8" then you could be in trouble...