peppie - It's either 100 gallon or 150 gallon resevoir. It should hold 80 to 120 gallons.
Since it is up against a corner, I was planning on using a plywood and 2x6 platform that is supported 3 different ways:
1. 5 Bottom braces pushing down and back on the wall studs. These are on both walls (1 on the short wall, 5 on the long wall). The long wall has a header made of 2 2x12s and this is currently carrying the weight of the ceiling and the floor above.
2. 4 heavy duty chains bolted through the ceiling studs.
3. Two 2x6 studs connected to the 2x6 frame of the platform.
My concern is balancing the distribution of the load between the three mechanisms so none experience the full weight of the resevoir.
wood color code: pink = 2x4s, yellow = 2x6, brown = 2x12