Conflicting Test Kits

[mat167]

I've tried to test my NO3 with 3 different kits. Hagen, API, and Red Sea. All three give different numbers. With Hagen, I get 10ppm. API gives 0ppm and Red Sea gives almost 100ppm. These are HUGE differences and would like to know which one I can trust, if any. Also, could someone suggest a better test kit? I am tempted to go with elos, but they are pricey.

 

[Mytir_Binsdirty]

elos or salifert are a very good choice...can i ask have you taken it to work yet?

 

[melev]

I've trusted Salifert for years. I ran out and had to get a different kit, and API seems to be okay. However, I think I need your kit since it reads a nice sexy zero.

 

[mat167]

I've trusted Salifert for years. I ran out and had to get a different kit, and API seems to be okay. However, I think I need your kit since it reads a nice sexy zero.

Yes, the persistent zero was eerily comforting, lol.

elos or salifert are a very good choice...can i ask have you taken it to work yet?

As in have I tested my water at work? Yes, and we use API tests there. Suspiciously enough, that one reads zero also. I'm fairly sure it isn't zero because I'm struggling with dinos and mild cyano, as well as rampant green algae. I think I'm gonna go grab an Elos NO3 test tomorrow and test it with that. Other than the NO3 test I've had good results with API which is why I don't understand the inconsistency.

 

[melev]

Check for PO4 since algae loves that stuff too.

 

[mat167]

PO4 is at 0.1ppm tested with Red Sea. Unfortunately I went out and bought a bunch of Red Sea tests from work, then a few days later I heard some pretty negative reviews. It reads about the same with the hagen test. I didn't use the API because I heard that under .5ppm it is totally inaccurate.

 

[mat167]

Ok so I thought I'd update. I got a salifert NO3 test. It reads ~25ppm. I redid the Hagen one and it's pretty close at ~20 ppm. As for the PO4 both hagen and red sea read the same at 0.1 ppm still.

 

[Billybeau1]

mat, The Salifert NO₃ kit is quite good at low levels of nitrate. It is not so hot at higher levels, say above 50 ppm.

Conversely, The API nitrate kit reads levels above 50 ppm much better than the Salifert.

For phosphate, you are correct in the API just does not detect below .5 ppm. Salifert or Elos is much better for that.

 

[schminksbro]

I bought an API alk kit and got conflicting results from my previous kit. I took a sample of my water to the lfs. They tested it with 5 different API kits and got a different reading on every one.

 

[Billybeau1]

<a href=showthread.php?s=&postid=13985132#post13985132 target=_blank>Originally posted</a> by schminksbro
I bought an API alk kit and got conflicting results from my previous kit. I took a sample of my water to the lfs. They tested it with 5 different API kits and got a different reading on every one.

I can believe that. That does not mean they are inaccurate. API measures to the 1 dkh. So any slight variation in testing may skew the results 2 dkh either way depending on how you view the final result.

Most API alk users test the same every time so the inconsistencies are limited. They also are not very concerned as long as they are with 2 dkh either way of their target alkalinity.

You still cannot beat it for the price.

 

[HighlandReefer]

I have bought a few API alk kits and have had the same conflicting results from one kit to the next kit. I threw mine away and now use Salifert. The only theory I have is that API is carried by most LFS, because of the price. They sit on the shelves and become old and are no longer accurate. I have seen LFS use the same API kit for testing water for a very long period of time.

edit: The test results were way off. In one case the alk. from one API kit was 11 and the next one I bought was 16. The Salifert kit read around the 11 mark. This happened several times.

 

[Billybeau1]

When one buys an API kit, you should open the box and look at the date on the bottles. If they are over 12 months old, I would not buy them.

 

[mat167]

yea I found out that it was the date. Oh by the way I got a salifert PO4 test and it reads 0 ppm. Sweet NO3 is a little high but I had been messing around in the sand recently and redoing rockwork...I guess that's why.

 

[Billybeau1]

:thumbsup: