What is the best UV water-cooling coolant?

Mayhems Pre-Mix X1 UV Red

Manufacturer: Mayhem's
UK price (as reviewed): £7.98 (inc VAT)
US price (as reviewed): $10.98 (ex TAX)

Mayhem's is currently in the limelight thanks to its quite frankly stunning-looking range of new coolants. They're available in a range of colours and pigments, and some also feature a pearlescent additive which looks simply awesome in clear reservoirs. On test here is its Pre-Mix X1 UV Red - a basic coolant by Mayhem's standard, which is coloured a deep red and claims to be UV reactive.

While the colour is nice too look at, offering a vivid shade of strawberry red, the same can't be said for the UV effect - it didn't seem to react at all to our UV cathode compared to the other red coolants, which is disappointing. Thankfully there were no issues to report in the thermal or flow rate performance - it performed pretty much the same as the Phobya ZuperZero UV Red and Nanoxia Hyperzero UV Green

As a straight colour, the Mayhems Pre-Mix X1 UV Red is a good buy - it's vivid and looks much more 'red' than the Phobya ZuperZero UV Red coolant. It's not one to go for if you want some fun in the dark though.

Nanoxia Hyperzero UV Green

Manufacturer: Nanoxia
UK price (as reviewed): £5.98 (inc VAT)
US price (as reviewed): N/A

Nanoxia is no stranger to PC cooling and the company is well known for its fans and other cooling paraphernalia. It's Hyperzero UV Green is the cheapest coolant on test too at just £5.98 - probably less than you'd pay for a 3L container of deionised water and additive when you factor in postage costs.

It looks stunning, and has a vivid green glow in daylight, and was spectacularly reactive under UV light. As with most of our testing, there wasn't much between it and the other coolants in terms of flow rate or thermal performance, but it was in the top three of the latter, with a delta T of 30°C.

It's cheap, looks great but more importantly is both cheaper and better-looking than any of the other coolants we tested. Whether you're on a budget or after some GREEN!!! coolant, this is the one to get.