This is a very common question which we often get asked across all our ranges of filters and sterilisers.
The typical answer for this, is always; ‘No, unfortunately not’.
The reason for this is, the ballast sizes which are built into many units are designed to be used with the wattage they come supplied with. If you were to fit a higher wattage bulb, the higher wattage demand would overwork the unit, increasing the chances of you causing damage to your unit or worse, risking it to overheat.
For this reason, we would always recommend only fitting the recommended wattage bulb for your unit. This also means we would not recommend lowering the wattage of the bulb.We offer a wide supply of bulbs on our website, allowing a constant supply of spare parts that you may need.  
We recommend changing bulbs every 6-8 months to prevent bulb blowouts as well as assist in keeping up the efficiency of your filtration.