Hey Shrike - it's the 25 gallon Botanicare res and cover... it is the one they use for their TurboGarden line of hydro units. It is a special order. You can find it online... let me measure it quick...Hey LionsRoor...what is the size (gal.'s & dimensions) of the reservoir you are using for your 3 post flower unit?
The res is 35 x 22 inches on the outside - but the actual interior section is 29.5 x 17 inches - it has a big lip. Also nice, it has a cut-out for the pump cord. The downside is, the cover and the res, with the porthole cover will set you back about $100.
To clarify - for those wanting to build a triple banger with this res - the outside edge of you posts must be 29.5 or less. This is pretty good... my fence posts sit 14" on center - with the holes 8" on center down each post.