Review: JBL CristalProfi m greenline internal power filter


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Bob Mehen puts this easy-clean shrimp-safe filter through its paces.

Freshwater shrimp have been a boom area in the last few years, with many manufacturers and retailers joining the gold rush to cater for the vast range of colourful crustaceans now available. This has been great news for those wanting to keep their shrimp in tip-top condition, but it’s also seen a large number of small aquariums and related products not designed for the purpose but emblazoned with 'great for shrimps', or similar, in an attempt to cash-in.

Now the trend has set down its roots and appears to be here for the long haul, some manufacturers are properly designing new products with shrimp in mind and the JBL CristalProfi m greenline internal power filter is an example of this.

Filtering a shrimp tank (or a tank filled with micro fish species or fry) has always carried a degree of risk and most shrimp keepers will have found a filter full of shrimp at some point, still alive if they’re lucky.

To reduce this risk, many have fallen back on that old fry tank favourite, the air-powered sponge filter, which is fine for small tanks but not always aesthetically pleasing for those wanting something more than shrimp

life support.

Like many internals, the CristalProfi m greenline is a simple piece of kit: a plastic box with a pump and some foam for mechanical and biological filtration. Where it differs, however, is how the pump and foam are positioned: the pump is held inside the body of the filter at its base and draws water through a large sheet of foam, meaning that the suction is

far more diffuse than on a traditional internal.

Likewise, the density of the 35ppi (pores per inch) foam and the tight fit of the filter body mean that inquisitive shrimp are unlikely to slip through and come face to face with the pump impeller.

Space-wise, the three-sided, bow-fronted shape of the filter means that it can fit snugly into the corner of most tanks. It’s attached with an innovative sucker design, engaged or released with the use of a small lever on the top of the filter — only long-term testing will show whether or not the silicone rubber material used for this sucker will stay supple.

The filter runs quietly and, if installed as shown in the instructions (with the top of the filter just above the water’s surface), it can be considered truly shrimp-safe.

If you are tempted to place the filter fully submerged, be aware that there is the chance that shrimp and fry could access the filter body via the slot on the top, which allows the sucker release leaver to move back and forth. Submerged this would also allow some water to bypass the foam.

However, I tested this, and the suction associated with the slot was not noticeable, so I suspect that no fish or shrimp would be sucked in against their will.

One drawback of large-scale foam filters is that when you lift them out to clean them, the dirty water held within the foam drains back into the tank.

JBL has overcome this by providing a service cover that clips over the front of the filter before you take it out. This, in combination with a valve on the base of the filter, allows clean water to drain back into the tank before you remove the filter for maintenance.

A small, glass thermometer that can be clipped on the front, further reduces clutter, and it is supplied with a two-metre cable.

There is a decent-sized space in the body of the filter behind the foam panel where other bagged media, such as carbon or phosphate removers, can be placed. The outflow for the filter is a fine slit on the top, which distributes the water flow in a gentle manner designed to help prevent CO2 loss in planted tanks.

The pump is rated at an energy-efficient 3.5W, providing an output of 200lph, with JBL rating the filter as suitable for tanks from 20 to 80 litres.

If required, you can expand the filter by adding Modul expansion kits (which simply clip onto the base) — with the only limits being the depth of your tank. However, the more you add, the weaker the intake flow as the pump's capacity remains the same.

The filter has a generous four-year warranty.


This is a great little filter for those wanting something safe that isn’t air powered for their shrimp and fry. It’s a little larger than some internals yet is unobtrusive and easily hidden.

The large foam panel will also be an ideal grazing site for shrimp and fry when the filter is mature.

Dimensions: Height 19cm, width 12.8cm, depth 6.5cm to 1.4cm on curved front. Each Modul expansion kit adds a further 11.7cm height.

Price: £34.54. Modul expansion unit, £12.29.

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