BRS Reef Calculator: Every Saltwater Supplement Calculations In One Place

I remember my first "real" aquarium. It was a 20-gallon long. I was therefore excited. I went to the pet growth and motto a filter rated for 75 gallons. I thought, "Hey, more is better, right?" Wrong. I turned that situation upon and my needy neon tetras were pinned adjoining the glass following they were in a Category 5 hurricane. That was my first lesson in the indefinite world of aquatic hardware. Everyone asks, What Size Aquarium Filter do I Need?, but the reply is rarely as easy as looking at the box.


If you are staring at a shelf of plastic boxes and glowing lights, wondering which one will keep your fish from swimming in their own filth, you aren't alone. It is a jungle out there. You desire positive water. You want healthy fish. You afterward don't want to spend $300 upon a canister filter for a single Siamese combat fish. Lets rupture next to how to pick the best aquarium filter size without losing your mind or your paycheck.

Understanding the GPH Myth and Reality

When you begin browsing, you will see a number called GPH or Gallons Per Hour. This is the holy grail of marketing. Most "experts" will say you that you dependence a turnover rate of 4 to 6 period your tank volume. So, if you have a 30-gallon tank, you habit a filter that moves 120 to 180 gallons per hour. This is the baseline for aquarium filtration flow rate.


But here is the secret: those numbers are measured behind an blank filter. when you amass carbon, sponges, and a handful of ceramic rings, that flow drops by 30%. Then, a week later, considering some fish poop and pass tree-plant leaves acquire high and dry in the intake, it drops even more. I call this the "Sludge Coefficient." It is a measure term I use to remind myself that a clean filter is a fast filter, and a dirty filter is a slow one. subsequently asking what size aquarium filter pull off I need, always motivation for a GPH that is slightly superior than the "recommended" minimum to account for this inevitable slowdown.

The Bio-Load Variable: Its Not Just practically Gallons

A gallon of water is just a gallon of water, but what lives in it changes everything. This is where the aquarium filter capacity gets tricky. Let's compare two tanks. Tank A is a 20-gallon tank later than three tiny fancy guppies. Tank B is a 20-gallon tank gone two messy goldfish.


If you use the adequate 4x rule, both dependence an 80 GPH filter. But goldfish are basically poop machines later than fins. They develop a deafening amount of ammonia. For the guppies, a little internal capability filter is plenty. For those goldfish? You might habit a canister filter size rated for a 55-gallon tank just to keep the water from turning into toxic soup. This is what we call bio-load management. Your aquarium bioload determines your filter size more than the glass dimensions do.


I past tried to save a colony of snails in a 10-gallon tank bearing in mind a little sponge filter. Within a week, the "Nitrogen Equation" (another term I use for the bank account of waste vs. bacteria) crashed. The water smelled with a swamp. I realized that for stuffy hitters subsequent to snails, goldfish, or cichlids, you craving to double or even triple your filtration surface area.

Types of Filters and Their Sizing Quirks
Hang-On-Back (HOB) Filters

These are the most common. They sit on the rim. They are easy to clean. like picking a Hang-On-Back filter, see for one past flexible flow. Why? Because sometimes you realize you bought a unit that is too powerful. innate dexterous to dial it assist saves your fish from exhaustion. For a 29-gallon tank, I usually suggest an HOB filter rated for 50 gallons. It gives you that additional "oomph" without taking happening manner inside the tank.

Canister Filters

These are the heavyweights. They sit under the stand. They have gigantic amounts of biological filtration media. If you are asking what size canister filter get I habit for a 75 gallon tank?, the answer is usually "the biggest one that fits in your cabinet." Canisters are good because they don't lose as much flow to evaporation or surface tension. Plus, you can conceal every your heaters and gadgets inside them.

Sponge Filters

Don't snooze on the mortify sponge. If you have a shrimp tank or a fry grow-out, a frightful power filter will just suck your livestock up. A sponge filter is sized by the volume of the sponge itself. A "medium" sponge is usually good for whatever up to 20 gallons. They aren't good for mechanical filtration (getting the visible loose bits out), but for biological stability, they are gold.

The 70/30 rule of Filter Media

Here is a concept I developed after years of dealings and brs reef calculator error: The 70/30 Mechanical-to-Bio split. Most people think they craving a big filter to catch every the "dirt." Actually, 70% of your filter's job is invisible. Its the bacteria lively on the media. once you are looking at aquarium filter specifications, don't just look at the pump speed. see at the basket size.


A filter as soon as a tall GPH but a tiny tiny basket for media is considering a sports car in the same way as a lawnmower gas tank. It looks fast, but it cant keep the run. You want a large media facility filter correspondingly that you can house enough "good bacteria" to handle the ammonia spikes. This is especially real if you are a "lazy" hobbyist when me who forgets a water fine-tune now and then.

Specific Recommendations for Common Tank Sizes
What Size Filter for a 10 Gallon Tank?

Keep it simple. A little HOB filter rated for 15-20 gallons is perfect. Or, go in the same way as a large sponge filter. You don't obsession a canister here. Its overkill. If you have a Betta, make certain the flow is baffled. Bettas despise tall current. They have those long, trailing fins that achievement taking into account sails, and a strong filter will literally blow them around.

What Size Filter for a 20 Gallon Tank?

The 20-gallon is the "gateway" tank. For a 20-gallon tall or long, I recommend an aquarium talent filter rated for 30 to 40 gallons. This gives you room to grow your fish population. If you are produce a result a planted tank, see for something in imitation of a "skimmer" add-on to keep the surface positive of oily film.

What Size Filter for a 55 Gallon Tank?

Now we are getting into massive territory. A 55-gallon tank is narrow and long. This means poor water circulation at the ends. I often recommend using two smaller filtersone at each endrather than one giant one. Two HOB filters rated for 30 gallons each will make a much augmented "Circular Flow Pattern" than one big one that leaves "dead zones" where poop accumulates.

The quiet Flow Paradox

Here is something no one tells you: big filters are loud. Well, not always, but often. If your aquarium is in your bedroom, asking What Size Aquarium Filter do I Need? along with involves asking "How much noise can I snooze through?"


Larger canister filters are generally quieter because the motor is enclosed in a pail below the tank. Internal filters are furthermore quiet because they are submerged. But they give a positive response up pretentious swimming space. I bearing in mind had a 40-gallon breeder behind a "monster" HOB filter that vibrated consequently loudly it drove my cat crazy. I eventually switched to a submersible skill filter, and we both finally got some sleep.

When Over-Filtration Becomes a Problem

Can you have too much filtration? Yes. Its called "The Whirlpool Effect." If the water is disturbing so fast that your natural world are monster ripped out of the substrate, your filter is too big. Additionally, extreme flow can prevent the beneficial bacteria from settling. Its like trying to build a home in a hurricane.


There is after that the "Oxygen Saturation" issue. though oxygen is good, too much surface radio alarm in a CO2-injected planted tank will gash off all your expensive CO2. In that case, you desire low-flow, high-volume filtration. This means a big canister filter past the output vaporizer bar aimed slightly downward.

Maintenance and the "Long-Term" Size Choice

When we talk practically aquarium filter sizing, we have to chat approximately how often you want to attach your hands in fish water. A small filter gets clogged quickly. If you buy a filter that is "just enough" for your tank, you will be cleaning it all single week.


If you buy a filter that is "over-sized" for your tank (say, a 50-gallon filter upon a 20-gallon tank), you might be skilled to go three or four weeks between cleanings. The further mechanical filtration sponges can sustain more gunk before they start to overflow or slow down. For me, that supplementary $20 spent upon a larger unit is worth it for the extra two weeks of Netflix mature I get otherwise of scrubbing sponges in a pail of dated tank water.

Breaking alongside the "Fake" Information: The Micro-Bubble Oxygenation Theory

You might hear some people talk very nearly "Micro-Bubble Oxygenation" as a reason to get a huge filter. They allegation that tiny bubbles produced by high-flow filters permeate the fishs skin. unmodified bomb: thats mostly nonsense. Fish breathe through their gills. even though surface buzzer is vital for gas exchange, you don't compulsion a plane engine to pull off it. A simple air stone or a moderately sized filter output does the job. Don't allow a salesperson persuade you that you compulsion a "Turbo-Air-Intake" model just for the sake of oxygen.

Final Thoughts upon Choosing Your Filter

Choosing the right size is very nearly balance. You are balancing the volume of water, the number of fish, the type of fish, and your own willingness to pull off maintenance.


If you are just starting and someone asks you, "What Size Aquarium Filter complete I Need?", tell them to see at the manufacturer's rating and then go one step up. If the bin says "for 20-30 gallons," use it for a 20-gallon. If you have a 30-gallon, acquire the one that says "for 40-55 gallons."


Don't forget to adjudicate the filter media types. You desire a fusion of foam, ceramic, and maybe some chemical media considering Purigen or carbon. A improved filter housing gives you more room to experiment bearing in mind these.


At the end of the day, your fish will tell you if you got it right. If they are gasping at the surface, you need more oxygen (and maybe a enlarged filter). If they are hiding at the rear rocks to flee the current, your filter is too strong. And if the water is yellow and smells like a wet dog? Well, its become old to restore your filtration system.


Aquariums are supposed to be relaxing. Don't allow the complex jargon of GPH, turnover rates, and bio-load put emphasis on you out. begin in the same way as a reputable brand, size occurring slightly, and save an eye on your water parameters. Your finned contacts will thank youand they might even end looking at you considering you're the one who turned their home into a washing machine.


So, go ahead. affect that tank. Check your aquarium water volume. after that go get a filter that makes your water look correspondingly positive it's with your fish are in the air through skinny air. That's the dream, right? Just keep the flow below control, and youll be the master of your own underwater universe.