TetraPond Kits are both reliable and accurate, using professionally designed methods to determine if your water is safe for Koi Fish.
Nitrite is produced from the breakdown of ammonia in the filter. Nitrite is highly toxic to fish, but is usually removed from the water by the bacteria which live inside the filter. However, in new ponds, or if the filter bacteria are damaged, the nitrite level may become toxic.
The only way to know what the nitrite level is, is by testing the water with a TetraPond Nitrite kit. Regular testing, especially in new ponds, will prevent damage caused by nitrite poisoning.