u/FalconNo68

Hey guys i currently have a small tank (40cm x 23cm x 25cm) with regular black sand, a small internal filter and a cheap led tube light (10 white leds, 12 color leds).

What is the minimum amount required to make it planted (including substrate, lights, plants)?

i asked my LFS but they said that i cant maintain it and it be minimum 5k

i dont have any experience so suggest simple methods.

Thanks