The short version
A planted tank needs, in priority order: a tank (start with 20 gallons if you can; nano is harder), a light matched to your plant choices, substrate that either stores nutrients or that you can dose around, a filter that moves water without shredding plants, a heater sized to your room, and a test kit to know what’s happening. Everything else — CO2, timers, ferts, pre-filters — is situational.
Tank size
Twenty gallons is a forgiving size. Big enough to buffer parameter swings, small enough to fit most apartments, cheap enough to replace if you crack it. A ten gallon works, but beginners often underestimate how quickly nitrate climbs in a small tank. Anything under five gallons is advanced mode; skip it for a first tank.
Tall vs long: long wins for planted tanks. More surface area, more floor plant real estate, easier CO2 diffusion.
Light
Light drives everything. Too little and plants limp along; too much without CO2 and you grow algae. Match your light to your plant selection:
- Low-tech plants (Java fern, Anubias, Cryptocoryne): A budget LED like a Hygger 957 is sufficient. Run it 6–8 hours per day.
- Medium-tech (stem plants, swords, carpets on dirt): A Fluval Plant 3.0 or equivalent. Dimmable is worth paying for.
- High-tech (red plants, demanding carpets, CO2 injection): A Chihiros WRGB II or ADA-class light. These systems fight back if you under-light.
Substrate
Two schools of thought:
- Active substrate (Fluval Stratum, ADA Aqua Soil) — releases nutrients, buffers pH down. Growth is faster; shrimp like it. Breaks down over 2–3 years and must be replaced.
- Inert substrate (Eco-Complete, gravel) — doesn’t break down, doesn’t swing pH. You dose fertilizers to feed plants. More stable long-term; less convenient week-to-week.
Pick active for shrimp and fast plant growth. Pick inert for simplicity and large tanks.
Filter
For a planted tank, filter flow should turn over the water 4–6× per hour in real flow (not rated flow). That means a 20 gallon tank wants a filter rated for 100–150 GPH actual, which typically means rated 150–250 GPH.
Canisters are quieter. HOBs are cheaper and easier to maintain. Sponge filters are for shrimp and fry tanks.
Heater
Size the heater to tank volume and room temperature, not just volume. A 50-watt heater is fine for a 10 gallon in a 70°F room; the same tank in a 60°F basement needs more. Rule of thumb: 5 watts per gallon in a warm room, 7–10 in a cold one.
Preset “plug and play” heaters fail eventually and always at the wrong time. Glass heaters with external dials (Eheim Jager) are the old-reliable pick.
CO2 (only for high-tech)
Injected CO2 is the dividing line between “my plants grow” and “my plants explode.” If you want carpeting plants, red plants, or heavy pruning weekends, you want CO2. Regulator choice matters — cheap regulators do end-of-tank-dumps that kill fish. CO2Art Pro-SE is the floor; anything cheaper is a gamble.
If you’re starting out, skip CO2. Grow low-tech plants for six months, understand your tank, then upgrade.
Test kit
You need to know ammonia, nitrite, nitrate, and pH. Liquid test kits (API Master) are accurate, cheap per test, and take 3 minutes. Test strips are faster and less accurate. For a first tank, test twice a week for the first month, then weekly.
What you don’t need
- Airstones (planted tanks are oxygenated by plants during the day).
- A UV sterilizer (unless you have a specific algae outbreak).
- A chiller (unless you’re in a hot room keeping cold-water species).
- A smart controller (nice, not necessary).
Order of operations
- Buy the tank. Let it sit. Look at it. Plan.
- Add substrate.
- Install heater and filter (don’t plug in yet).
- Plant heavy. Denser than feels right. You can always remove later; filling gaps is harder.
- Fill slowly with dechlorinated water.
- Plug in heater and filter. Run for 1–4 weeks fishless with an ammonia source.
- Test until you see ammonia → 0, nitrite → 0, nitrate climbing. That’s a cycled tank.
- Add fish gradually.