API
£8.48 for 130 tests, 0.07p per test
I have used this, does what it says on the tin, very cheap. Two different reagents need to be used which is about average for ammonia testing
Nutrafin Freshwater Ammonia Testing
£6.39 for 70 tests, 0.09p per test
I have used this, one reagent only which is handy and an "instant" result, no waiting about
Nutrafin Freshwater and Marine Ammonia Testing
£5.99 for 50 tests, 0.12p per test
This used to actually be my favourite before i had issues with false-positive results of all ammonia testing kits. The reason i liked this one, was that it was quite easy to see small ammonia traces based on the colours in test tube, easier that all other ammonia test kits i have used. The downside of this kit is (a) 3 different reagents you have to use and (b) results take 20 minutes
Sera
£7.45 for 60 tests, 0.12p per test
Never used it! although i do like/trust the Sera brand
Salifert
£6.95 for 50 tests, 0.14p per test
Never used it!
Interpet
£6.50 for 40 tests, 0.16 per test
Never used it!
Seachem
£12.95 for 75 tests, 0.17 per test
Tried this as it shows up only the toxic form of ammonia, unlike most other ammonia kits. This was a big let down for me, it involves fiddling about with little paper "dots" and placing them in water then reading the colour change, big pain, difficult to read the results, waste of money for me.
JBL
£8.99 for 50 tests, 0.18 per test
Never used it! although i do like/trust the JBL brand
Tetra
£7.40 for 25 tests, 0.30p per test
Never used it, at 30p per test, Tetra are having a laugh. I have seen the colour chart and its basically the same kind of test as all other much cheaper kits. I cant see how they are justifying 25 tests for £7.40. Nothing to suggest there is extra value for money here