Thread from the WWn Wiki - originally developed by Andrew
2.1 Bottle-Based Backpack
2.2 PVC Pipe Backpack
2.3 Hydration Pack Backpack
2.4 Solar Shower Backpack
For any blaster to work it needs a source of water. There are many methods of providing a source of water for the blaster the most useful of which depends on the size and purpose of the blaster. A standard stock blaster will generally have some form of onboard reservoir which stores the water, and in some cases acts as the pressure chamber as well (see: Pressurised Reservoir Blasters). Smaller blasters with lower outputs can easily manage with an onboard reservoir only, but larger and more powerful blasters (notably elastic pressure, CPS or homemade blasters) drain their resources much faster and require a larger reservoir as a result. Due to limitations in size, cost and weight (large onboard reservoirs make blasters heavy when full), some blasters which perhaps should have larger capacity reservoirs, have to make do without.
Some blasters (notably the CPS 3000) had comfortable backpack based reservoirs which allowed the user to carry around greater quantities of water with little effort. A backpack reservoir removes the majority of the weight of the blaster to one's back, allowing the blaster to remain as light as possible.
It is possible to construct a homemade backpack, either to modify a stock blaster with a puny reservoir, or to give a homemade beast the capacity it needs.
Backpack reservoir designs can vary depending on the availability of materials, capacity required and user comfort. Below are some of the most common backpack designs.
 Bottle-Based Backpack
You will need:
One or more plastic bottles of whatever size you choose
Plastic or rubber hose
Glue / epoxy / duct tape
Threaded barb connectors / quick clip hose connectors
The bottle-based backpack is by far the most basic design of backpack reservoir. It is essentially one or more bottles of water attached to a hose which is attached to the blaster. The difficulty of this type of backpack varies depending on how you go about connecting the bottles. If you simply fit a flexible hose to the bottom of a large water bottle then the porcess is pretty simple. If you opt to cut holes in the bottles then it will be harder to make everything watertight
 PVC Pipe Backpack
 Hydration Pack Backpack
 Solar Shower Backpack