Re: Koi Angels on a killing spree NOT GUILTY (maybe)
A large fully-grown angel would probably take a neon but I'd be very surprised indeed if one could ever take a harlequin. When small fish die, the bodies are tiny and are quickly chewed up by other inhabitants, so you often don't find anything.
Incidentally, Stress Coat and Tap Safe are both tap water conditioners, so you don't have to use both at once. It won't do any harm, but it is an unnecessary outlay.
There have been some slight changes to this - API are changing over to printing expiry dates on the reagent bottles as well as the Lot#, to make things clearer. Many or most reagent bottles will now have this. It will say something like "EXP 08/2017".
Also, the life span of all the reagents has been extended to 5 years, except for calcium reagents, copper reagents, phosphate reagents, GH reagents, and the wide-range pH that is in the pond test kits - all these are still at 3 years.
When I saw this thread I mentioned it to the Head of Scientific Affairs at API. He wrote me a response, which I thought I'd post here for people to read.
Ranges for chemical measurements have limits. The lower limit is important because it determines whether a measurement is different from zero. The maximum Test Kit Detection Limit is important because this is the upper limit that any test kit can provide an answer for 99% level of confidence. All API Test Kits show the detection limits clearly on the packaging, instructions and colour charts.
API Test Kits are designed for use under normal conditions found within an aquatic environment (aquariums and ponds). The tests allow for, and are designed for, interferences and limited detection limits. When test results appear inaccurate, develop an unexpected colour or develop an unusual turbidity, repeating the test using a diluted sample with deionized water may be useful.(Dilution of samples is not appropriate for all tests, such as pH).
As an example the API Nitrite Kit is designed to provide accurate results from 0 to 5 ppm (mg/L). Under extreme conditions as high as 25 ppm (mg/L) the Nitrite Test Kit will still show a positive nitrite result but darker than the highest colour on the colour chart. A level of 25 ppm (mg/L) would be very unlikely in a home aquarium or pond and, of course, toxic to fish. Under even more extreme conditions, the API Nitrite Test Kit can be overwhelmed.
As an example I share the following to provide a better understanding of the API Nitrite Test Kit (liquid reagents):
At 0ppm Nitrite the test result reads as 0ppm Nitrite.
At 0.25ppm (mg/L) the test result reads as 0.25ppm (mg/L) Nitrite
At 1.0ppm (mg/L) the test result reads as 1.0ppm (mg/L) Nitrite
At 5.0ppm (mg/L) the test result reads as 5.0ppm (mg/L) Nitrite
At 25ppm (mg/L) Nitrite the test result stays deep purple for 5 minutes. (Note: purple colour is above the 5.0ppm top detection limit of the colour chart provided with the test kit)
At 50ppm (mg/L) Nitrite, the test result turns deep purple initially, but back to light blue after 5 minutes.
At 100ppm (mg/L) Nitrite, the test result turns deep purple initially, but back to light blue after 1.5 minutes.
At 1000ppm (mg/L) Nitrite, the test result turns light blue, never turning purple.
There were a couple of delays on this as people were on holiday, but I've had the scientific people at API in the States have a look at the video.
The consensus was that the first test tube must be contaminated in some way, or (although less likely) that the top of the dropper bottle is contaminated (such as by touching the top of the water in a previous test). This is the only way to get a different result - there must be something different that is present in the first test. It is not possible to get a different colour result just from the amount of water or the number of drops of reagent used - this will make the colour more or less intense, but not change the colour.
FishLady asked me to have a look at this thread, to see if I had any ideas about what could be happening with the API pH test. I haven't heard of this before to be honest. I don't know all the background to Kev's thread, but with any test kit anomaly, the first thing to check is that the kit is not expired, and that it hasn't been open for more than a year. If you can tell me what it says on the reagent bottle, I can tell you whether or not the test is expired (although that isn't likely of course, as they have long dates).
Assuming this is all fine, Kev, is there anything at all different about the subsequent tests? How long is it between tests - what happens if you test again after, say, an hour? Does it go back to being purple again or does it take a day or so between tests before the first one comes out purple again? Have you tried getting someone else to do the test from scratch, using your water and your test kit, and seeing what happens?
Anna - if you're still reading, could you possibly ask if a higher than normal level of Chlorine or Chloramine would affect the kit?
Hi Matt, yes, I'll ask. Sorry it's taken me so long to come back to this thread; the last couple of weeks have been rather hectic. If you need me quickly you can always PM me, as this comes into my email in-box and I see it straight away.
An extremely high level of ammonia usually reads as very dark green/blue. I even saw a result that looked very dark navy blue and almost black.
We have not found any other aquarium products, like conditioners or medications, to cause false readings with this ammonia kit. However, this is the 3rd or 4th strange result when someone was performing a fishless cycle using a liquid ammonia product. We have not done testing in this area, as these products are not meant for aquarium use. If you can get the name of the product, it may be something we can get here and try with the test kit. At this point, I can only guess that this particular ammonia product is somehow interfering with the test kit.
Another possibility is pH. Our test solutions, Bottle 1 and 2, create a certain pH in the test tube to allow the kit to read ammonia properly. The liquid ammonia product they are using may be drastically altering the pH and thereby interfering with the test results, especially when added directly to the test tube at high concentration. Again, we have never found any interference from products that are for aquarium use.