Eu,
Totally agree with what recommended by Yeemiau. Their development is affected by tank size and water depth.
I saw new 4' blue plastic tub selling RM180 without filter box (before nego). U don't need the filter box for keeping TVR.
If u want used tub, try this:
WTS - 4x2.5x1.5 Poly Tub- Cheap!!
Good luck,