API Reef Master Test Kit - 5ml vs 5ml

[xmike24]

I'm sure the title seems a little interesting... Let me explain.

1. I started out doing the tests with the 5ml mark that API has labeled on the little vials they came equipped with. Tests seemed fine except for Nitrates test which is jumping from 10 - 40 between tests. Seriously?

2. I read somewhere that they bought medical grade syringes to measure "true" 5ml... Well I did that, tried it out, and the 5ml mark according to the syringe is noticeable above the line.

Suggestions? Should I follow the medical grade 5ml?

 

[freeswimmingfis]

I use a medical grade syringe to measure 5ml. I dont even look at the line on the vial.

 

[bertoni]

We've wondered about this issue in the past. I guess I'd follow the manufacturer's marking, but we don't know which approach is more accurate, if either.

 

[ArrowCrab]

Is there any difference in the readings?

Slightly related, my test kit came with a mismarked vial where the 5ml line was marked as if the tube had been reversed, lol.

 

[xmike24]

Is there any difference in the readings?

Slightly related, my test kit came with a mismarked vial where the 5ml line was marked as if the tube had been reversed, lol.

It's funny you say that because I just checked my vial lines, all 4 along each other, with water filled by the syringe. Here's a photo of what mine looks like.

 

[bertoni]

Well, the difference is fairly small. I don't think it'd affect the results all that much.

 

[xmike24]

Well, the difference is fairly small. I don't think it'd affect the results all that much.

In regards to the photo, I was more referencing the fact that their manufactured lines are different. The difference is fairly small in the outside vials, the 2 middle it's a decent amount IMO.

 

[Cloudburst2000]

Which is a main reason I only use API test kits for ballpark figures on certain tests and I find the nitrates test to be one of their worst ones. I think they are pretty cheaply made which is why they are much less expensive then higher end test kits. When I first got into the hobby, I used API test kits as that is what my LFS sold. I then read that they often were not that accurate (more ballpark figures) so I started buying Salifret test kits also and have recently switched to the newer Red Sea kits plus a Hanna checker for phosphates. Since API is cheap to buy, I use them to measure tank parameters every couple days or so. I use the Salifret/Red Sea test kits to verify tank parameters less often. I always use the higher end test kits when doing my water changes. I tend to use the cheaper API kits when measuring parameters between water changes and only use the more expensive kits if I think something is off, I have made some type of change in the aquarium, or if the API kit sends back a suspicious number. The higher end test kits are too expensive to use as frequently as I test my tanks so I basically rely on API kits to verify that my numbers are staying stable.

 

[Spyderturbo007]

Which is a main reason I only use API test kits for ballpark figures on certain tests and I find the nitrates test to be one of their worst ones.

I'm in complete agreement. I don't have any issues with the API test for Nitrite, pH or Ammonia, but their Nitrate test sucks. I picked up one of the Red Sea kits and don't have any issues with that one. It's much easier to read and seems to be more repeatable.

 

[milomlo]

I have to say I am relatively new (back into the hobby after leaving for a few years) and I am using API now. I used Salifert years back. I am currently cycling my tank and my ammonia went from 1.00 to 0 back to .25 now and I have yet to see any trates at all. I only saw a HINT of nitrites before my ammonia went back to 0. I am not sure what's up with this.

 

[bertoni]

The difference in volume seems to be less than 10% or so, which is probably within the error limits of the test, although it's a bit sad to see such differences.

 

[EnV]

I have the same test, i'll have to to see if mine is off.

 

[Teddynola]

The discrepancy in the markings on the tubes is quite interesting. I don't use API tests much, anymore, but I always used a 10ml syringe to measure 5mls. One thing that confuses people is that if the mark is truly in the right spot, you measure at the bottom of the meniscus. The dip in the water line, not the water line at the edge of the glass. You can see what I mean in the post above with the API vials.

 

[Ron Reefman]

Our local club is doing a water testing meeting next month. Everybody who comes brings any and all test kits they want to check on. We will all use the same water and compare all the results. I expect we may even have some different readings from people using the same brand of kit. If we do, we will swap kits and do the test again to see if the readings follow the test kit or stay with the people who did the test, i.e. is it a test kit problem or a difference in how 2 people do the test. I hope it turns out some statistics that will help us. BTW, the water will also be tested by a local lab as a baseline.

 

[xmike24]

Our local club is doing a water testing meeting next month. Everybody who comes brings any and all test kits they want to check on. We will all use the same water and compare all the results. I expect we may even have some different readings from people using the same brand of kit. If we do, we will swap kits and do the test again to see if the readings follow the test kit or stay with the people who did the test, i.e. is it a test kit problem or a difference in how 2 people do the test. I hope it turns out some statistics that will help us. BTW, the water will also be tested by a local lab as a baseline.

Sounds fascinating. Hope you guys will be recording all the findings?

 

[disc1]

It's funny you say that because I just checked my vial lines, all 4 along each other, with water filled by the syringe. Here's a photo of what mine looks like.

I know that looks bad, but it's really an insignificant difference once you factor in the precision of the test kit. Looks like it's much less than 10% and I don't think there's a kit out there that has that level of precision. Definitely not an API.

For a calcium test for instance, what should have taken 10 drops now takes 9.8 drops. Since you cant measure fractions of a drop you're going to end up with the same number or at worst one drop off. You'll end up one drop of for myriad different reasons.

If this is for a colorimetric test, like a nitrate test, then the situation is even better. You are actually measuring concentration with reagents present in excess. So in reality small variations in sample size don't make any difference at all.

 

[Jstn]

Also remember to read a graduated cylinder by the bottom of the minuscus. This appears to make the volume more accurate

 

[tecapparatus]

only way to go is Class A glassware.

 

[etymotic]

Our local club is doing a water testing meeting next month. Everybody who comes brings any and all test kits they want to check on. We will all use the same water and compare all the results. I expect we may even have some different readings from people using the same brand of kit. If we do, we will swap kits and do the test again to see if the readings follow the test kit or stay with the people who did the test, i.e. is it a test kit problem or a difference in how 2 people do the test. I hope it turns out some statistics that will help us. BTW, the water will also be tested by a local lab as a baseline.

That sounds like a great idea!i I wish I lived in Florida. Will you posting the results anywhere?