High-Range pH test reagents

[angelminx]

I posted a comment on this in  the thread on the "How I Saved..." under "Problems and Mishaps".  I am having problems with the accuracy of my API High-Range reagents.  The last 2 refill bottles that I have bought have NOT been reading true.  If you'll refer to the previously mentioned thread and respond here, I will continue with this issue here.

Thanx, and sorry for the mix-up.

[Carl]

How is it you determined they are not testing true?

I myself have not found this to be the case with many brands I have used of the years, API included; ASSUMING NEW.

What is much more common is one brand producing different results from another.

If purchased from AAP, these can certainly be returned for us to test and confirm then replace if need be.

Carl

[angelminx]

I originally did a test with the "1st" ("current" at the time) High-Range test, and then did a comparison with the "new" reagent; I tested the most recent purchase with the "new" one I had purchased before.  They did not give the same readings.   BTW, I purchased them from a different website since I had to order something you didn't carry at the time I purchased them..

[devonjohnsgard]

So, if I'm understanding. You have two High Range test kits and they don't have the same readings?

Same brand? and what are the readings?

I checked over at the other thread, but I'm still unsure what the problem is.

[Deleted]

Greetings,

Did you check the expiration date on the bottles? Some online retailers do sell old product. If no expiration date, then there should at least be a lot number. You can contact API and they will let you know if that reagent is still good. I have been using API test kits since 2006 and never had a problem with any of them -- except a KH test kit that had expired (new kit was fine).

I am sure you already rinsed the test tube thoroughly so that isn't the issue. Once time a local store associate tested my sample water (that is the "rule" if I fish dies while still under guarantee) and told me my pH was too high (voiding the guarantee).... I went right home and brought in my own test kit with 2 clean test tubes and tested my water with my own kit - perfect 7.0.... I let him test it with his kit using my clean tube -- perfect 7.0. I have no idea what was contaminating the store test tube. After that, I just took in all my own tests and cards to prove my water was good....and also a sample of water in case they didn't believe me. I no longer buy fish from that store (corporate won't do anything to improve the quality of water and care the fish get at the store)... It is just a good place to buy cat litter now.

If the readings from the two are within .2 to .5 difference, I wouldn't worry about it. Just keep the water the same. For instance, my API test kit says my pH is 7.0 -- but my dip stick says it is 6.8....That works for me.

[angelminx]

Hi, Judy!

Both of my reagents are from API, and one is (expiration) dated 2/'19, and the other is 5/'19. My "low-range" pH reagents (both API; the nearly empty one is 3/'19 and the new bottle is 6/'19) read 7.6 (the color is so close to being dark enough that the reading may be just above 7.6). The High-Range reagents come back with readings of ~7.4, and ~7.5 (hard to match the color with the jump from 7.4 to 7.8 on the card). The "original" bottle of High-Range reagent, that I ran out of, read ~0.2 or 0.3 higher than the present "old" bottle. If only it wasn't so hard to distinguish some of the readings. I wish there was more of an overlap between the normal and High-Range tests, and that there wasn't that jump between readings (7.2-7.6 and 7.4-7.8, respectively)on the cards. I wouldn't be quite so concerned if my normal range wasn't right there in that area. I have problems getting the lower pH (I'd rather keep it at ~7.4), and at the same time keeping my KH up(which I'd prefer to keep at ~5 degrees). I sometimes struggle to keep my KH at 3 degrees.

I've never had problems with my API reagents before.

Angelminx

[Carl]

If I am correctly understanding, the problem is the difference between the API high range and low range test kits?

If this is the issue, this is not all that abnormal, as these use different chemical reagents.

BTW, Judy made an excellent point about rinsing your vials well between use.
Using DI (not tap or even RO) water would be best for this rinsing for the best accuracy

Carl

[angelminx]

Hi, Carl,

Determining the pH (between the "division" point of the 2 tests) can be confusing, since the colors/pH numbers on the cards have that big jump in the readings on the upper/lower ends, so I am not always sure what the actual pH is. However, the thing that disturbs me most is that the 2 new reagent bottles don't quite agree with each other, or the "original" bottle. As I have said, I've never come across this before in all the years I have used API's reagents--even back when they did not print the expiration dates on the bottles.

Would distilled water work? I usually rinse out the test tubes after each use (5x) with hot water, to help them dry out faster. I also have dedicated tubes for each tank (and for tap water samples).

Angelminx

[Carl]

Distilled is DI water, just another term/method for achieving it

Carl

[angelminx]

Thanks, Carl. I can never remember the differences/which terms go with which!

Angelminx