
Check₂O Aquarium Nitrite
Check₂O Aquarium Nitrite
0 - 0.5 - 1 - 5 - 10 mg/L NO₂⁻
Nitrite is also extremely toxic to aquatic life. Nitrite is formed by the conversion of ammonia via nitrifying bacteria on biofilters. Ideally, no nitrite should be present in aquariums but 0.75ppm is the level where stress is induced. Nitrite is removed from aquariums via the same biofilter and nitrifying bacteria by conversion to nitrate, but this takes time. Nitrite is usually removed via a complete water change.

Frequently Asked Questions
Clear answers to help you choose the right water testing solution with confidence
Which brands of water testing kits do you supply?
Do you provide kits for both home and professional use?
Yes — whether you’re a pool or spa owner, aquarium keeper, utility company, or a university laboratory, we have the right solution for your needs.
Can I arrange servicing or calibration for my photometer?
Absolutely. We also provide servicing and calibration to keep your photometers accurate and reliable.
How quickly do you dispatch orders?
Orders placed before 2:30 pm (Monday–Friday) are dispatched the same day. We also ship on Saturdays for your convenience.
Which couriers do you use for delivery?
We deliver through UPS, DPD, and Royal Mail. You can also choose to upgrade to next-day delivery at checkout.
What is your return policy?
We accept returns within 14 days of delivery provided the items are unused, in their original packaging, and in resalable condition. Please contact our team before returning any items.
Can I place bulk or business orders?
Yes, we welcome bulk, trade, and institutional orders. For tailored pricing or large quantities, please get in touch with us directly.
How can I get help if I’m unsure which kit to buy?
You can call us at 📞 +44 (0)115888 2726 and our team will guide you in choosing the most suitable kit for your needs.