Review: JBL Pro Cristal i30 internal filter


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Review: JBL Pro Cristal i30 internal filter

Bob Mehen takes a look at this new addition to the nano market.

'Nano' sized aquaria seem to be an unstoppable trend in the hobby at present, offering fishkeeping opportunities for those without the space, budget or inclination to shell out for a larger aquarium. 

Many of these tiny tanks come in a 'plug and play' state, with all the required equipment in the box, but there are a significant number of small tanks around that either don’t feature filtration at all, or are hamstrung by poor designs. Many of the offered filters are the smallest that the manufacturer makes, and often little more than a tiny version of what they make for larger tanks. 

German manufacturer JBL has been recently been confronting this with a series of innovative new internals to suit various applications. 

The newest of these is the Pro Cristal i30. This diminutive filter is aimed at tanks between 10 and 40 l; squarely at the 'nano' market. At 12cm/4.8in high, 7.5cm/3in wide and 4cm/1.6in thick, it’s compact and easy to place discreetly in most tanks. 

The majority of the media space is taken up by a standard sponge insert that’s ideal for both physical and biological filtration purposes if maintained well. The i30 goes a little further, with the addition of chemical filtration cartridges that slot into a purpose built housing below the filter outlet. 


Currently two different cartridges are available; 'Algae Prevent' and 'Super Clear', both of which are recommended for monthly replacement. Budget conscious fishkeepers, not averse to a little DIY tinkering, could try emptying the spent cartridges and adding their own choice of chemical media which would increase options. 

The i30 is expandable via ‘Modul’ units which clip to the base of the filter, with each unit doubling the amount of foam media. This makes the unit bulkier, adding 4cm height with each one, but the 200 lph pump, (rated at a frugal 3.7W) is gutsy enough to deal with extra loading — within reason. 

A ‘Venturi’ aeration device is included for those after increased surface agitation, and the i30 fixes to the tank via sucker cups. Only long-term testing will show if these suffer from issues of hardening and the associated loss of adhesion that can affect suckers. 

The i30 can also be installed lying on its back in shallow tanks, as long as the unit remains submerged. 

The packaging does mention its use in goldfish aquaria, though PFK doesn’t recommend keeping goldfish in tanks of sizes between 10 and 40 l (Feature ed’s note: unless it’s a rearing tank for fry, that is). 

There’s a manufacturer’s four-year warranty too! 


If you’re in the market for a nano-filter, whether to replace or upgrade existing kit, or in a new tank then the i30 is well worth serious consideration. Compact, adaptable, quiet and economical, it ticks all the boxes for smaller tank filtration.

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