Fluval Flex Aquarium Kit, White - 34L & 57L

The Fluval Flex Aquarium Kit, White is Fluval's curved-front glass aquarium in white, sold in 34 and 57 litres, with the filter and pump hidden in a compartment at the back.

Key Features

• Vertically bent front glass rather than a flat pane, which is what gives the Flex its curved look
• Rear filtration compartment hides the pump and media behind the honeycomb print, so there is no hardware in the display
• Remote-controlled LED lighting
• Designated heater channel in the rear compartment (heater sold separately)
• Whisper-quiet circulation pump on rubberised feet
• Three-stage filtration in the rear compartment: foam, carbon and BIOMAX biological media
• Two sizes: 34 L and 57 L
• White cabinet-style frame, which suits a lighter room than the black version
• Made by Fluval, the aquatics brand of Rolf C. Hagen, which has been building aquarium filters since 1975

Setting It Up

• Put it where it will live before you add water. A full aquarium cannot be moved, and glass on an uneven surface cracks
• Check what the furniture underneath can take. Water weighs a kilo a litre before you add glass, gravel and rock
• A new tank has no bacteria in it. Cycling — running the filter for several weeks until it processes ammonia and nitrite to zero — has to happen before fish go in, or they sit in their own waste while the bacteria catch up
• Plant it and let it settle for a few weeks before the first fish. A tank that has been running a month is a far kinder place to arrive in
• Add fish a few at a time, not all at once

Living With It

• The rear compartment is where all the maintenance happens
• Never wash biological media in tap water and never replace it all at once. Chlorine kills the bacteria living on it, and changing everything together restarts the cycle
• Keep the water topped up to the line in the rear chamber, or the pump will suck air
• White surrounds show algae and hard-water marks more than black ones. Wipe the top edges when you do a water change
• Unplug anything electrical before putting your hands in the tank

Good To Know

• Stocking is the thing beginners get wrong. Ask what the fish grows into, not what it is in the shop — most tropicals sold at 2 cm do not stay that size
• Nothing in this kit heats the water unless stated. Tropical fish need a heater; a heater is sized at roughly 1 watt per litre
• A liquid test kit for ammonia, nitrite and nitrate tells you more about a tank than anything you can see
• Most tanks want 20–30% of the water changed weekly, with the replacement dechlorinated and matched for temperature
• 34 L is a small tank. It suits a group of small fish or a single betta with a heater
• No heater is included in either size
• Use a soft algae pad on the curved front, never a blade