Test Kit brands (again?)

OnyxFishies · Oct 2, 2004

All I've been able to gather so far about different test kit brands so far:

Most Ammonia, NitrIte and NitrAte test kits are reliable enough for hobbyist use.
Most test kits by Hach and LaMotte are good quality but expensive. (and hard to find, at least for me)
Most pH test kits are not very precise.
Most Fe and K test kits are horrible.

My question is this: What test kit brands do you guys and gals use/recommend?

I use Aquarium Pharmaceuticals NH3, NO3, NO2, and pH test kits. Is there a brand that has a good pH test kit? I can't afford the electronic pH meters that I've seen online, so I think I'm stuck with using dropper bottle reagent type tests. The Aquarium Pharm. test kit I have for pH is fairly imprecise, only has color matches for .2 intervals in the middle of the range, and the pH in my tanks stays near the lower end of the range, 6.4 to 6.8 or so.

I just bought a KH/Alkalinity test kit made by Salifert. Anyone have any experience with this brand? It has a fairly complicated procedure involving a dropper bottle for the indicator and two different syringes, one for tank water and one for the reagent. As such, it seems to be be fairly decent in resolution.

I'm looking for a good PO4 test kit.. Is the tetra test kit for PO4 any good?

Also: I know some test kits are meant for salt water. Which ones only work well with salt water, and which ones can be used for fresh or salt?

Thanks for all your help!

beviking · Oct 4, 2004

I also use Aquarium Pharmaceuticals NH3, NO3, NO2, and pH test kits. The ph I have goes from 6.0-7.6 (it's the low end pH kit) in .2 increments too. I agree the colors are tough to discern, but if you use the same lighting to read your reading, you should be able to be fairly accurate. I don't think being off .2 (or .4) is going to be crucial.

I bought a Hagen PO4 kit and I like it! I measured 0ppm-PO4, then added enough Fleet Enema to give me .5pp (by calculations) and sure enough, the kit measured .5ppm!

This is a color chart too, but it goes from clear-->dk.blue with varying shades of blue.
I then bought Hagens Fe kit. It measured Non-chelated and chelated iron. Same deal, measured 0ppm, my Big Al's Multi has .24% Fe chelate so I added 40mls (which should give me ~.3) and viola, meaured higher than .25, not quite as dark as .5 Fe (chelated). Again, this chart starts clear at 0, next is a light purplish/blue 0.1, then darker blue 0.25, darker blue 0.50, dark blue 1.0. Even if you're color blind (no joke, I have family that is) you can read these charts b/c they go light to dark.
I'm glad I got the Fe kit. I'm too paranoid of adding too much that I was only adding 1/2 of what I should.

HTH

Indigo · Oct 4, 2004

I have the Hagen test kits. I bought a kit that has NH3, NO2, pH high and pH low, gH and kH. Then with my tank I got a wide range pH test kit for 'free,' and I just picked up the NO3 kit from my LFS a couple weeks ago. I don't have experience with a wide range of kits, just from testing my parents pool and chem class

They seem pretty accurate. I've compared my tap water results that the city publishes on what's in the water, and its pretty close IMO. The only thing I don't like is that I have a hard time differentiating between shades on the results sheet. 2.6ppm NH3 looks a lot like 4.9ppm *shrug* maybe my eyeballs are shot

happychem · Oct 5, 2004

I'm curious where you read that pH kits are not very precise. Acid-base indicators are quite rugged as far as test kits go, as long as you stay within the limitations of a particular indicator.

I use Hagen test kits, they're what's most widely available around here. Plus, I know the reactions that they use. I suppose it's the same with AP test kits. I can reproduce the city's water report to within the sensitivity of the test kits, so I'm happy.

With test kits, look more for changes than absolute numbers. Most of the kits are spectrometric, which means measuring the intensity of a colour. The kits get around the need for relatively expensive apparatus and standards by printing standard colours on the box/insert, but this means the your test is only as good as your eye interpreting the colour and as good as their printer reproducing it. Although, I agree with Beviking that they do seem quite good at coming very close.

OnyxFishies · Oct 7, 2004

happychem said:
I'm curious where you read that pH kits are not very precise. Acid-base indicators are quite rugged as far as test kits go, as long as you stay within the limitations of a particular indicator.

Augh. I've looked, and googled until I could google no more. I *thought* I read that aquarium pH tests aren't very precise, but I can't find it. More likely I inferred it (incorrectly, It seems!

) from the various places on the web with aquarium and plant information.

Thanks!

PS: Love your new sig, happychem. It is from "The Prince's Bride"? Very funny movie.

cgrabe · Oct 7, 2004

Maybe you were reading something about the pH test strips?

happychem · Oct 7, 2004

Test strips can be tricky, especially if they're not kept right. And by right, I mean not too dry, not too wet, not in the light and not in too much heat.

Although perhaps you read that pH kits weren't terribly accurate? Accuracy refers to how close you are to the true value, precision to how reproducible your readings are. Acid-base indicators will show the same thing every time, but there is often a question of interpretation. For example, I've a heck of a time telling the difference between pH 6.6 and 6.8 with a bromothymol blue indicator. If the pH is a clear 6.6, well, probably something like 6.55 (complete guess), then I can pick out 6.6 from the colour chart. Anything between the two is a realy tough call, and it makes a world of difference when tryign to estimate CO2 concentrations.

So I think that my take would be that the pH kits (liquid) are very precise, but that their accuracy may be questionable depending on the pH, the indicator colour at that pH and the colour change in that region.

This brings me to a more general point about any analytical method. The closer you get to the limits of that method, the more difficult it is to be certain of your answer.

NatakuTseng · Oct 7, 2004

I like the Sera line of test kits. Partial to most sera stuff I guess, hard to come by I believe for a lot of people. I think there is only one or two distributors in the US, fortunately one of them is down in MA just south of us and deals directly with our LFS. Great german quality.

Captain Hook · Oct 8, 2004

I use the Tetra test kit pack. The only thing I wish it had is nitrate.


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Test Kit brands (again?)

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