Best Filter for a Planted Tank: Top Picks for Every Budget

Published 3 June 2026

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A good filter is the most important piece of equipment in any planted aquarium. It houses the beneficial bacteria that keep your water safe, maintains circulation, and keeps the tank clear. The wrong filter — too powerful, wrong type, or undersized — leads to stressed fish, uprooted plants, and water quality problems.

Here’s what actually matters when choosing a filter for a planted tank, and which options we recommend for each scenario.

What to look for in a planted tank filter

Appropriate flow rate: The general guideline is a filter that turns over 4–6x the tank volume per hour. A 40L tank needs a filter rated for at least 160–240 litres per hour. More isn’t always better — excessive flow can uproot plants and stress fish.

Gentle output: Fast-moving streams of water are damaging in a planted tank. Sponge filters, spray bars, and baffled outputs distribute flow gently. Powerheads and strong internal filters create current that disturbs fine-leaved plants and stresses fish that prefer calmer water (bettas, shrimp).

Good biological media capacity: The filter needs sufficient surface area for beneficial bacteria. Sponge and canister filters excel here. Thin cartridge-based HOBs are weakest.

Easy maintenance: A filter you avoid cleaning is a problem filter. Sponge filters take 2 minutes; canisters take longer. Match your maintenance tolerance to the filter type.

Filter types: which suits a planted tank?

Sponge filters

Best for: small tanks (up to 40–50L), shrimp tanks, betta tanks, quarantine tanks, breeding setups.

Sponge filters are air-powered and produce extremely gentle flow — ideal for shrimp, bettas, and small fish that prefer calm water. The large sponge surface provides excellent biological filtration and the gentle bubbling aerates the water adequately. They’re inexpensive, reliable, and almost impossible to clog catastrophically.

The main limitation is aesthetic: the airline and air pump aren’t invisible. Some hobbyists hide the air pump outside the tank cabinet.

Who should choose this: shrimp keepers, betta owners, anyone on a tight budget, anyone with a small tank.

Hang-on-back (HOB) filters

Best for: tanks of 20–100L, community setups, beginners who want simple maintenance.

HOB filters clip to the back of the tank and draw water up through an intake, through filter media, then cascade it back in. They’re easy to set up, easy to maintain, and widely available. For a standard community planted tank, a good HOB is often the cleanest, most practical solution.

Key consideration for planted tanks: the output waterfall creates surface agitation that looks attractive but can reduce CO2 in the water. For a low-tech planted tank this isn’t a concern (you’re not dosing CO2). For high-tech setups, an in-tank spray bar or reduced flow is preferable.

Who should choose this: beginners, community tank setups, tanks up to 100L.

Canister filters

Best for: larger tanks (75L+), setups where filtration must be hidden, aquascapes where aesthetics matter, tanks with heavy bioloads.

Canister filters sit outside the tank (usually in the cabinet below) and use a separate intake and output tube. They provide excellent filtration volume, are very quiet, and keep all equipment outside the tank for a clean look. The spray bar output is ideal for planted tanks — it distributes flow evenly across the surface without the waterfall effect.

The trade-off is maintenance: canisters are more work to clean (usually every 2–3 months) and more expensive. They’re also overkill for a simple 40L beginner setup.

Who should choose this: experienced hobbyists, larger tanks, scapers who want clean aesthetics.

Our recommendations by scenario

Best sponge filter for betta / shrimp tanks

Hygger Double Sponge Filter — reliable, good biological surface area, available in multiple sizes. Pair with a cheap air pump (Tetra Whisper or similar).

Azoo Mignon Filter 60 — a small internal HOB-style filter with very gentle output. Good option if you want a self-contained unit without external airline.

Best HOB filter for a beginner planted tank (40–75L)

Aquaclear 30 / Aquaclear 50 — consistently rated as the best value HOB filters in the hobby. The media chamber is larger than most HOBs of the same rating (meaning more beneficial bacteria), and the flow is adjustable. The Aquaclear 30 suits tanks up to 110L by manufacturer rating; for planted tanks with moderate stocking, the 30 is appropriate for 40–60L.

Seachem Tidal 35 — a strong alternative with a self-priming pump (no need to manually prime), a surface skimmer built in, and an audible alert when media needs replacing. Well-regarded for planted tanks.

Best canister filter for a planted tank (75L+)

Fluval 207 / 307 — reliable workhorse canisters with good media capacity. The 207 suits tanks up to 220L (well oversized for most home planted tanks, which improves performance). Includes spray bar.

Oase BioMaster 250 / 350 — premium option with a built-in heater chamber and easy-access media baskets. Higher upfront cost but extremely convenient maintenance.

What to avoid

Generic “starter kit” filters included with cheap tank packages — these are often underpowered, use proprietary cartridges you must replace regularly (expensive ongoing cost), and have minimal biological media capacity. If your tank came with a filter, check whether it’s adequate for your tank size before relying on it.

Filters rated for exactly your tank size — always size up slightly. A filter rated for 50L on a 50L tank is running at maximum capacity. Something rated for 75–100L on that same tank has headroom.

Very cheap internal power filters — fine for fish-only tanks; too strong and noisy for planted tanks with bettas or shrimp.

Filter maintenance: the most important thing nobody tells you

Whatever filter you choose, never clean the filter media in tap water. Tap water contains chlorine and chloramines that kill the beneficial bacteria living in the sponge or bio-media. Those bacteria are why your tank is safe.

Clean filter media by rinsing it gently in a bucket of water siphoned from the tank during a water change. Do this only when flow is noticeably reduced — not on a fixed schedule. Over-cleaning a filter causes more problems than under-cleaning.

For the full setup guide including how to cycle your filter before adding fish, see our low-tech planted tank guide.