Biox Aqua Chlorine Dioxide Tablets review
Pyramid Biox Aqua Chlorine Dioxide Tablets (30 pack)
By Tom Calder
Chlorine dioxide is the most capable chemical option for a kit like this, dealing with Cryptosporidium and Giardia that older iodine and chlorine tablets can miss, and it leaves little of the usual pool-water aftertaste. Individually foil-wrapped with a long shelf life, it is a sensible, low-cost item to keep in a grab bag.
- Best for
- A compact chemical backup for a grab bag, treating clear water on the move.
- Skip it if
- Your aim is to supply a whole household through a prolonged outage or to remove chemical…
as of 2 Nov 2026, 16:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.We earn a commission if you buy through the retailer links on this page. It doesn't change our verdict. How we make money →
Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- Chlorine dioxide tackles bacteria, viruses and the tougher cysts (Cryptosporidium, Giardia) that some cheaper tablets do not
- Very little chemical aftertaste compared with standard chlorine tablets
- Small and light enough to live in a grab bag or glovebox
Worth knowing
- One tablet per litre means 30 tablets only treat 30 litres, which is modest for a household or a long outage
- You wait 10-30 minutes per litre and should pre-filter cloudy water first, so it is slower and fiddlier than a pump or gravity filter
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Our review
Pyramid's Biox Aqua tablets use chlorine dioxide rather than plain chlorine, which is why they can claim Cryptosporidium and Giardia as well as bacteria and viruses. A pack of 30 treats up to 30 litres, weighs 25 g and fits in a glovebox. The trade is time: Pyramid quotes 10 minutes, but the US Centers for Disease Control says to follow the label, and for cysts that can mean a much longer wait.
What they are
Pyramid Travel Products describes Biox Aqua as tablets that treat up to 30 litres, so one tablet per litre, and says they are effective against bacteria, viruses, Cryptosporidium and Giardia, for tap, stored or river water. The pack is 30 tablets in a 6 by 9 cm box weighing 25 g. Pyramid's own site would not load for us, so we have taken its product text from a UK stockist's page and its claims should be read as the maker's, not an independent test.
Why chlorine dioxide
Ordinary chlorine tablets do not kill Cryptosporidium, a parasite found in farm run-off and some surface water. The CDC's emergency water guidance says chlorine dioxide tablets will kill Cryptosporidium as long as you follow the instructions correctly, and it gives no fixed wait time for chlorine dioxide, deferring to the label. That is the whole reason to carry this tablet rather than a cheaper chlorine one. Chlorine dioxide also leaves less of the swimming-pool taste.
Pyramid's quoted time is 10 minutes. We could not confirm from the maker whether that covers cysts or only bacteria and viruses; other chlorine dioxide products give several hours for Cryptosporidium in cold water. The safe reading is to treat 10 minutes as the minimum for clear, cool water and to wait longer, following the pack, if the source could carry cysts.
Using them
Drop one tablet in a litre of clear water, cap it, wait and drink. Cloudy water needs straining through a clean cloth or a filter first, because particles shelter germs. Tablets do nothing about mud, chemicals, fuel or metals, so flood water needs a different approach. The government's Be Ready advice is to follow the instructions on the label, since tablets come in different strengths, and that most alternative water sources will need filtering before tablets are used. During a boil water notice your water company's instructions come first. Our guide to purifying water in an emergency compares boiling, filtering and tablets.
Pyramid publishes no shelf life that we could find, so write the purchase date on the box and replace the pack every few years.
How they compare
On the purification tablet page, the one-litre Aquatabs and the 10-litre Aquatabs 67 mg are cheaper per litre and better documented, but make no Cryptosporidium claim. Katadyn's Micropur Forte adds silver to preserve stored water. The Biox Aqua is the only tablet we list with a chlorine dioxide claim against cysts, and 30 litres is a grab-bag quantity, not a household's.
Our verdict
The tablet to carry if your likely water is a stream, a river or a farm tap rather than a stored container, for the Cryptosporidium claim. Buy a pack for the car and the grab bag. Skip it as your main household treatment: for filled containers of tap water the chlorine tablets are cheaper and better documented, and a filter plus boiling does more.
A researched review, built from the maker's specs, manual and UK listings; facts checked 2 Nov 2026. Sources: Ibex Camping: Pyramid Biox Aqua water treatment tablets (maker's product text); CDC: Making water safe in an emergency; GOV.UK Be Ready: water supply interruptions or outages.
Who shouldn't buy this
Don't buy these if your aim is to supply a whole household through a prolonged outage or to remove chemical contaminants or heavy metals; tablets only handle microbes in modest volumes, so a stored-water container plus a gravity or pump filter is the better backbone, with tablets as a light top-up.
Key specs
| Treats per tablet | 1 |
| Active agent | Chlorine dioxide |
| Pack size | 30 |
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the UK price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
Best for A compact, long-shelf-life water backup for a grab bag or travel where you cannot boil or filter.
as of 2 Nov 2026, 16:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.Questions
How long do Biox Aqua tablets take to work?
Pyramid quotes 10 minutes. The CDC says to follow the label for chlorine dioxide, and cysts such as Cryptosporidium can need longer in cold water, so wait longer if the source is doubtful.
Do they kill Cryptosporidium?
Pyramid claims Cryptosporidium and Giardia as well as bacteria and viruses, and the CDC says chlorine dioxide tablets will kill Cryptosporidium if the instructions are followed. Plain chlorine tablets do not.
How much water does a pack treat?
Up to 30 litres from 30 tablets, so one tablet per litre of clear water.
Do they work on cloudy water?
Strain cloudy water through a clean cloth or filter first. Tablets disinfect; they do not remove silt, chemicals or metals.
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