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How to set up a canister filter without a dry start

Updated: 23 October 2026

The canister is out of the box, the tank is full, and the impeller has to start wet. How to set up a canister filter depends on which pot you bought, because a Fluval 07 and an Oase FiltoSmart 60 do not share a first step. This page is the start, the placement, and the tests for the first month. A qualifying purchase from the main [canister filter comparison](/hub/diy-supplies/canister-filter) can earn a commission at no extra cost to you. Which model belongs on your litres is the [canister filter buying guide](/hub/diy-supplies/canister-filter/sub/canister-filter-buying-guide). A drip after it is running belongs on [canister filter leaking](/hub/diy-supplies/canister-filter/sub/canister-filter-leaking). The single pick for a 60–220 litre tank is [best canister filter](/hub/diy-supplies/canister-filter/sub/canister-filter-best).

The canister is out of the box, the tank is full, and the impeller has to start wet.

Our top picks

Fluval Fluval 207 external filter

Best overall

Fluval Fluval 207 external filter
9.2/10about £124.99
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Oase Oase FiltoSmart 60

Best value

Oase Oase FiltoSmart 60
7.8/10about £43.56
View offer
Unbranded 1,800 L/h external canister

Alternative

Unbranded 1,800 L/h external canister
7.6/10about £99.99
View offer
On this page
  1. 1.Put the canister below the tank and fit the hoses
  2. 2.Prime a Fluval 07 without filling the pot first
  3. 3.Start an Oase FiltoSmart 60 by filling it
  4. 4.What to test while the tank settles
  5. 5.When setup stops being a setup

Put the canister below the tank and fit the hoses

Fluval’s 07 manual, which covers the 107, 207, and 307, wants the canister upright and below the aquarium, gravity-fed. The distance from the bottom of the canister to the maximum water level must not exceed 1.4 m, and the water level should sit no more than about 17.5 cm below the rim. Hoses take a short, straight path, without a loop that traps air. Seat the Fluval gasket moist, fully in the channel, with the cover in its only orientation and the lift-lock clamps closed. One Fluval 107 review describes a first install that dragged on because the silicone seal went in the wrong way. Oase states a head of 0.70 m, and the unit can sit beside or behind the tank.

Prime a Fluval 07 without filling the pot first

Fluval’s manual tells you not to fill the 07 canister with water before you start. Copying the Oase fill onto a 207 is how the impeller can run dry. Open the AquaStop lever all the way, then pump the prime handle about three or four times until water is drawn in. Keep the output nozzle slightly above the surface while air is leaving. Wait until the bubbling stops and the canister is full, and only then connect the mains. The two unbranded listings state a pull-vent of two to five pumps. The AQQA listing does not state a prime method. Reviews mention a priming button, with no stroke count.
Fluval Fluval 207 external filter

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Fluval Fluval 207 external filter
9.2/10about £124.99
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Start an Oase FiltoSmart 60 by filling it

The FiltoSmart 60 is self-venting, and the instructions tell you to fill the container completely. The pump must never run dry. Rinse new media before that fill, route a drip loop so water on the flex does not run into the socket, then connect the mains. Air takes several minutes to leave, and the unit is noisy while it does. The head is 0.70 m, so a canister on the floor well below a tall tank can be outside the lift Oase states. When the return is steady, the next job is the water test.

What to test while the tank settles

Once fish are in the tank, OATA’s freshwater sheet says ammonia and nitrite should be zero, and that you test at least weekly. This category has no measured cycle length in days. On later cleans, rinse Biomax in aquarium water and do not replace all the media at once. New Fluval media may be rinsed under the tap once, before first use, to wash off dust. If ammonia will not fall after you have stopped feeding, get help, especially where fish are dying.

When setup stops being a setup

A seal fitted the wrong way, a drip on the floor, or water near a socket is no longer a prime. If the plug and the socket are dry, disconnect at the plug, shut the valve, and catch the water. If the plug or the socket is already wet, do not pull that plug by hand. Isolate the circuit at the fuse or breaker first, then unplug. When you cannot isolate it safely, stop and get help. A damaged cable or plug is the same stop. The setup is finished when the return is steady and the stocked tank reads zero ammonia and zero nitrite.

Common questions

How do I prime a Fluval 207 or 307 before I switch it on?
Leave the canister empty of a pre-fill. Seat the moist gasket, lock the clamps, and push the AquaStop lever all the way open. Pump the prime handle about three or four times until water is drawn in. Hold the output slightly above the surface until bubbling stops and the pot is full, then plug in. The 107 uses the same 07 manual.
Should I fill a Fluval 07 canister with water first?
The Fluval 07 manual says not to fill the canister with water before the prime. The prime handle is what draws water in, over about three or four strokes, with the AquaStop fully open. Filling the pot first is the Oase FiltoSmart instruction, and the two starts are different products. A dry impeller is a fault. Plug the Fluval in only once bubbling has stopped and the canister is full.
How do I start an Oase FiltoSmart 60?
Rinse the new media, fill the container completely, and never run the pump dry. Route a drip loop, then connect the mains. Expect several minutes of noise and bubbles while air leaves. The stated head is 0.70 m, and the hose in the set is 1 m of 8/12 mm tube, which you shorten so it does not kink. Bracket 45051 is not in the box.
What do I test in the first month?
Once the tank is stocked, OATA says ammonia and nitrite should be zero, and that you test at least weekly. Clear water is not that test. Fishless dosing pages in the UK describe about 3 ppm or about 4 ppm of ammonia. Those are two methods for an empty tank, not the home target after fish are added. These sources do not give a number of days for a cycle.
Can I rinse all the biological media under hot tap water?
Hot tap water is the wrong rinse for biological media you want to keep. Fluval’s manual says to rinse Biomax in aquarium water, and never to replace all the media at once. A single tap rinse of new media, before first use, is the manual’s way to remove dust, and it is not permission for the later cleans. Changing every sponge and all the biomedia together strips the colony the canister was bought to hold.

Related pages

Fluval 207 or 307

Canister filter

Best canister filter when the tank is 60–220 litres

Canister filter buying guide: match the stated litres

Canister filter leaking from the seal, hose, or body

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 22 October 2026.

  1. Fluval 07 series, UK (retrieved 22 October 2026)
  2. Fluval 07 manual (retrieved 22 October 2026)
  3. Oase FiltoSmart 60, en-GB (retrieved 22 October 2026)
  4. GOV.UK: Electrical Equipment (Safety) Regulations 2016 (retrieved 22 October 2026)
  5. legislation.gov.uk: SI 2016/1101 regulation 35 (retrieved 22 October 2026)
  6. OATA: how to test freshwater aquarium water (retrieved 22 October 2026)
  7. OATA water quality criteria, October 2022 (retrieved 22 October 2026)
  8. Maidenhead Aquatics: Fluval 07 (retrieved 22 October 2026)