What low-tech means
Low-tech is shorthand for no CO2 injection, modest light, and plants that tolerate lower CO2 and nutrient levels. It’s the easiest path to a stable, attractive planted tank.
Plant choices
Stick to Java fern, Anubias, Cryptocoryne, Vallisneria, Amazon sword, and stem plants from the Rotala and Ludwigia genera that tolerate low-tech. Avoid carpeting plants (they need CO2 to carpet), red plants (except a few hardy ones), and anything described as “demanding”.
Light
A cheap-to-midrange LED run 6 hours per day. Longer than 6 hours in a low-tech tank feeds algae more than plants. Start with less; increase only if plants stall.
Fertilizer
One all-in-one liquid fertilizer (Thrive, Easy Green, Tropica Specialised) dosed once weekly. If you have active substrate, dose less; if inert, dose the label amount.
What breaks
Low-tech tanks fail slowly, almost always from not enough plants in the first six months. Algae wins when nutrients outpace plant uptake. Fix: plant heavier than feels right, reduce light duration, add faster-growing stems.