Tetra and API test Kits... same tank, different results

[chesspupil]

I recently purchased a Tetra Kit so that I could test my KH level which was not in the API test kit. Just out of curiosity I ran the Ammonia test with the Tetra... Conducting both tests per their individual directions and under bright light evaluation here are my results:
Ammonia:
API test kit says 1ppm, or more,
Tetra says 0.25ppm
Results were repeated with each kit giving the same result on the second try.
Which company do you trust? Why?

 

[mfdrookie516]

Assuming neither kit has expired, I would go with the API results. The reason I say that is because of something someone posted on here recently. They said that the 5ml mark on the API kit is actually less than 5ml. This means that if the kit is calibrated to measure the PPM of ammonia/nitrite/nitrate of 5ml of water, it will test a little higher with less water. That said, you're testing for 0 on ammonia and nitrite (assuming this is a cycled aquarium). If one test reads .25 and one reads 1ppm, you still have ammonia. The fact that you think you have 1ppm (even if it may be a little lower) means you need to do something. Neither are acceptable levels IMO, which means I would be doing PWC's to get it down.

Again, this is all my opinion. While some people want an accurate number, I think I would prefer that any ammonia/nitrite be amplified so that I know they're there and can act accordingly.

 

[chesspupil]

These are both Liquid tests. I see no way of knowing the date of manufacture from either test though API does use a cryptic LOT # system.

 

[mfdrookie516]

Im not sure on the other kit, but the lot number on API kits tells the date of manufacture. I want to say the first two are month and second two are year.. but I can't remember for sure.

 

[ejaramillo01]

You right mfdrookie, the bottle, not the box, should have the lot number printed, with an ink jet printer, the last four digits of the number mean the month and year when the bottle was manufactured.

API said that a bottle with more than 3 years must be discharged.

The bad part is that if you have been using the bottles for a while, the print trends to smear or even disappear just with the rubbing of the fingers.

 

[fort384]

I gotta agree with rook. It doesn't matter if it's .25 or 1. The only acceptable number is 0. The fact that there is detectable ammonia means action is required.