Frequently asked questions
Is ultrasonic cleaning safe for coated lenses?+
Yes – the NURO system was built exactly for this. Cleaning is contact-free, so no micro-scratches occur. Mirrored and polarized sports lenses handle the cleaning without issue too. Our fluids (Klarberg × NURO Concentrate and NURO Premium Fluid) are pH-neutral and tuned for premium coatings. Exception: lenses with damaged coatings or antique mirror finishes – when in doubt, ask our support.
How do you dose the Klarberg × NURO Concentrate?+
One teaspoon (approx. 5 ml) of concentrate per tank fill – that matches the 1:20 mixing ratio with water. The exact dosage is also printed on the included product insert.
Why does wiping sports eyewear with a jersey or cloth damage the coating?+
Dry wiping drags embedded sweat-salt, dust and sand particles across the lens surface like fine sandpaper. Over time this creates micro-scratches that attack anti-reflective or hydrophobic coatings. Ultrasonic cleaning lifts these particles contact-free via cavitation – with zero friction on the lens.
Do I need a cleaning fluid at all?+
No. NURO cleans very well with plain water – 48,000 vibrations per second do the work. Our fluids speed things up with sweat salts, grease and styling residue, and additionally care for coatings.
How often should I clean my glasses in the ultrasonic bath?+
Sports eyewear: ideally after every sweaty session – sweat salts are the most common cause of corroded hinges. Everyday glasses: once or twice a week is plenty.
What is the difference between the Concentrate and the Premium Fluid?+
The Klarberg × NURO Concentrate is the pro formula: highly concentrated (1:20), up to 400 cycles per litre, ideal for intensive studio use. The NURO Premium Fluid is our gentler in-house formula for daily use at home – fragrance-free and biodegradable.
Can I clean jewellery and watches too?+
Jewellery: yes, except soft stones (pearls, opals, amber) and glued settings. Watches: only waterproof models, or straps separately – the included watch holder keeps the case above the bath.
How loud is the device?+
Under 45 dB – quieter than a fridge. The NURO hum is practically unnoticeable in a salon or hotel.
Do you offer invoice payment for businesses?+
Yes. Business customers (studios, salons, hotels, bike cafés, opticians) simply send a B2B inquiry via the contact form – we reply within one business day with a tailored offer including invoice payment.
Is this scientifically backed?+
Yes. A study by Furtwangen University (Fritz et al., Scientific Reports 2020) found over 5,232 bacterial species on worn spectacles. An earlier study by the same research group (PLOS ONE 2018) showed: wet cleaning removes 99–100% of germs, while dry wiping with a cloth removes only 85–90%.
What is your return policy?+
All our products can be returned within 14 days. Return shipping is at your own cost. Please note: once the ultrasonic cleaner has been put into use with water, a return is usually no longer possible for hygiene reasons.
Do you ship outside Germany?+
Currently we ship with Hermes (€5.79, free from €100) within Germany. More countries (including Austria) are coming – register via the contact form and we'll let you know at launch.