I use 15 gallons of water for 3 plants and 20 for 4 which gets me through 7 days with no major PH or PPM swings. When I think Hydro I just naturally think lots of water with true high pressure aeroponic being the exception.
Upgrade you rez and watch your PH and PPM problems wash away
I really like the tough totes from Lowe's Hardware they are black, excellent for holding back light, with bright yellow tops you can't miss them. The yellow lids aren't totally light proof but if it's not directly under the light it's probally o.k. as I don't cover mine but the room it is in only has the light on when I'm in there.
Oh, larger amounts of water will hold its temp better also.
Here is the formula for finding the number of gallons in a square or rectangular container.
Measure the interior length, width, and depth of a rectangular or square container.
Calculate the container's volume in cubic inches (Find the volume of each of the pieces by multiplying the height by the width and then multiplying the product by the length. This will tell you the cubic inches in the volume.)
Divide the total number of cubic inches by 231 to get the number of gallons in the container.
Good Luck...Looking good otherwise
I don't have to chase the PH which is sooooooooooooooooooooooo nice!