Review: Gyractor G400 bio reactor from Arcadia


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The Gyractor G400 in-sump bio reactor manufactured by Bio Aquatek Ltd provides a new twist in the bio-pellet reactor market, writes Levi Major.

Powered by an 8w SICCE Silent 0.5 synchronous pump, water is forced through a unique fluidising plate on the bottom of the reactor, keeping the Bio Pearls media in suspension whilst turning it over to allow even water dispersal.

A clever little baffle plate has been included in the top to keep the bio pellets inside without having to resort to using easily clogged sponges.

The Gyractor G400 requires much less maintenance than some other reactors.

The dual action of this reactor agitates the media at the bottom, tumbling dead bacteria off and allowing growth of fresh biofilm.  

At 37cm/14.5” tall and with a footprint of 11cm x 14cm/4.3 x 5.5” it’s capable of fluidising up to 400ml of bio-pellet media.

The cylinder itself is constructed from Class A acrylic and ABS for rugged durability.

The Gyractor G400 comes complete with the extremely quiet Sicce pump, tubing and a 250ml sample of Marine Bio-Pearls and is quite conceivably all you need to grow those nutrient-stripping bacteria.

There’s little to be negative about, but I take issue with the supposed "specially designed key lock head for easy removal." The locking mechanism is preferable to having multiple nylon nuts and bolts, but trying to marry the main reactor body to the base can be tricky due to the ‘O’ ring.

When you put the media into the reactor you need to upend the unit and the ring inevitably falls from its recess. It’s tricky keeping this in place while engaging the base into a locked position.

The supplied tubing is too small to fit on the 1.3cm/0.5” hose tail at the top of the reactor and either requires patience and hot water to stretch it to fit or replacing with an appropriate diameter tubing.

Of all the reactors I have used this unit comes very close to the top of my list. It’s affordable and more or less ready to go straight from the box — with the exception of the supplied tubing.  

Eight watts of power consumption won’t break the bank to run, or add any noticeable heat to the system, and once operating it requires minimal maintenance until the bio-pellets need topping up.

Price: £139.99. More info from

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