I have wondered for a while now why in the drop test kits ( I have Nurafin Mini Master kit) that come with PH Ammonia , Nitrites and Nitrates that there are different volumes for the tests. With both the No2 and NO3 tests the two bottles you mix together one is 10ml and the other 5ml when you use the same amount of drops in each. So one lot is going to run out before the other. Doesn't make sense to me

Serioulsy? It really doesn't make sense to me either... in fact, it makes no sense I've just checked all my test kits and they're matched drop for drop

Maybe its just the one i've got then

Ive just gone to look at mine and its the same, got a small bottle as well as the bigger one. No idea why they would do that either.
I just use the strips twice a week and the bottles maybe once a month.

Im not sure but check the size of the drops. Maybe the smaller bottle has a smaller drop that comes out.

Courtnie - you put your finger right on it.

The drop size will be different. It may be a rather dramatic difference or a very subtle one, but it is different.

Even the AP drop tests such as the 2 part nitrate test have different drop sizes. But they give you bottles with the same amounts in them. That is why you will always have a bit left over in the one bottle when the other is gone. Since they are so close to the same, it is not worth it to do it differently. (costs more to make separate bottles, etc. than the small amount of chemical involved).

Thanks for that. The dropper size definately makes sense.

I test for NO3 more often then I test for NO2, especially since I know my tank is cycled. Therfore I use more NO3 test solution than NO2 test solution.

Kevin