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Setup

Canister Filter Setup

Setting up a canister filter is one of those things that, when done incorrectly, can really do damage to your tank — but when done correctly, makes everything significantly easier to take care of. For some reason, it was really hard to find a consistent answer when I started this hobby — it's very easy to find a hundred different ways to do it.

I've tried practically every combination possible, and what I'm sharing here is the best combination of both simple and effective that will work in 99% of cases. It's exactly what I do on every single tank I set up.

What to Look For

  1. 1
    Size
    Get the largest one you can while keeping tubing size consistent across all your tanks. I personally run 16/22mm on everything.
  2. 2
    Self-priming
    One button to start it. No sucking water through a tube.
  3. 3
    Quick disconnect
    So you can pull it for cleaning without making a mess every time.
  4. 4
    Adjustable flow valve (Optional)
    It's preferred that it's built into the filter. Otherwise, no worries — you can buy an adjustable flow valve to put into the tubing, like the UNS Delta Double Valve Connect.
  5. 5
    Pre-filter (Optional)
    Makes maintenance slightly easier. This is helpful, but largely overrated in my opinion — if you over-filter your water like I do (using a more powerful filter than needed, or running two filters on larger tanks), you won't need to do maintenance often anyway.

What Size Canister Filter Do I Need?

No more accidentally swallowing tank water sucking from tubing.

A simple rule of thumb: aim for 5–10x your tank's volume in gallons per hour (GPH).

100–200 GPH
Recommended filter flow rate

The number above is your total filter flow — it doesn't need to come from a single filter. For example, an 80-gallon tank needs 400–800 GPH total, which you could get from two 400 GPH filters running together instead of one large one.

Media Calculator

Figure out exactly what goes in each basket, bottom to top — first is always mechanical, last is always chemical, everything in between is biological.

By default, this shows flow from the bottom basket to the top, which is how most canister filters run. If yours flows top to bottom instead, hit Reverse Flow below to match your setup.

Flow

A few rough rules of thumb

  • Fill each basket to about the 75% mark — don't pack it 100% full. Water needs room to flow through.
  • Chemical (Purigen): roughly 200g for a 20-gallon tank, at least 400g for anything larger.
  • Biological (Matrix): given the 75% rule above, put in as much as you're able to.
  • Mechanical: pillow stuffing instead of filter floss — it does the same job, costs less, and doesn't need to be cut to size like floss does.

My Recommendation — Fluval 407

The Fluval 407 hits every one of those criteria at the lowest price point with solid build quality.

It's not the most expensive filter on the market — but you're never going to see it anyway. It sits under your tank and does its job. There's no reason to spend more.

Other options

Any other 16/22mm filter that hits those five criteria is generally fine too.

Other recommended brands: the UNS Delta 120 and the Oase Biomaster series are both solid options. They're all about the same, so I just buy whichever one I can get for the cheapest price.

Pro tip

Look on Facebook Marketplace for people selling used canister filters or new, unused ones — both usually go for a steep discount. I get most of my filters used to save money.