I have a 20L with a modified aqua clear rated for 70g. Small nano pump with a 4 t5s and a 250w halide.

I used cycled water and LR from my dads 190g established tank and new sand. It took about 3 weeks for my tank to fully cycle.

I do small water changes weekly with RODI water and things have been running great. Especially since I went from just t5s to a halide setup.