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I have been using the 6 in 1 test strips but ive read loads that there not very accurate so i looked into getting an API testing kit but then realised they sell one for freshwater and one for saltwater. Having a brackish tank i dont know which one i need to use. At the minute im mixing 5 grams per litre. Does anyone know which test i need please?

Based on this post on another forum the actual test is the same, it's just which tests are part of the "Master kit" that varies. I haven't looked into it further than that, but it makes some sense that there are different things that are important for the different setups.

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Mats

I use this one http://www.petsolutions.com/C/Aquarium- ... r-Kit.aspx

Judge for yourself: you are at ~0.5% of salt (5 g in 1000 g of water). Fresh water is zero-to-550 ppm of salt (550 ppm = 0.55 parts per thousand = 0.055 parts per hundred = 0.055% - maximum allowable by the US government for tap water). Salt water is 3% to 4% of salt, typically. You are much closer to the fresh water than to the salt water - I'd use a fresh water kit.

Sara1210 wrote:there not very accurate

IMO, nothing is "very accurate" that is short of an official, analytical chemistry lab test = $100's or $1000's. Strips are crude, mostly yes/no, much/little type of test. Liquid tests are more accurate but that's all one can say - "more". I'd recommend using a reference in your testing, at least for starters and then sporadically - e.g., do not just measure NH3 in your tank water but compare the vial to the same test of your tap water.

I once looked up the accuracy of a paper strip nitrite test - which is also used by hospitals to check for urinary tract infection. It is about 85% accurate at high levels of nitrite, but it reduces to about 60% detection rate at lower levels of nitrite.

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Mats

MatsP wrote:I once looked up the accuracy of a paper strip nitrite test - which is also used by hospitals to check for urinary tract infection. It is about 85% accurate at high levels of nitrite, but it reduces to about 60% detection rate at lower levels of nitrite.

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Mats

My god thats naughty

Thanks for your answers guys ill get myself the freshwater test and see how i get on

If you go to the API web-site (link provided if you follow the link above), you can see each individual test kit - e.g. nitrate test, and it shows whether it is "freshwater/saltwater" or "freshwater only" (you may have to try to decipher the label or read the text, as they don't make it entirely easy). But in summary, for the majority of the tests, the salt makes no difference. There are a few tests that are specifically for freshwater, but those aren't the ones you get in the Master Freshwater (or Master Marine) packages.

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Mats

As a suggestion, you can ask the manufacturer about which of their test kits would be the best for your application.

Scleropages wrote:As a suggestion, you can ask the manufacturer about which of their test kits would be the best for your application.

This is the best (& most obvious) piece of advice i've seen in ages - definately the way forward - nice one Scleropages

Well, but if you check the pages for API's individual test kits for:
pH, High Range pH, Ammonia, Nitrite and Nitrate
pH: Freshwater only - however, this has to do with the range of 6.0 - 7.6, which is not suitable for marine fish!
High Range pH: The package says "Fresh water and Saltwater". This is stating "for marine, Rift Lake Cichlids and very alkaline water" in the blurb.
Ammonia: Clearly states "Freshwater and saltwater" on the package.
Nitrate: Web-page says "Measures nitrate levels in both fresh & saltwater aquariums. Tests nitrate levels from 0 to 160 ppm. 90 tests per kit."
Nitrite: Package says "Freshwater and saltwater".

I'm not sure why, if the tests included in the Master Freshwater kit all are labeled as "Freshwater and Saltwater" on the packaging for the individual tests, one would have to ask the supplier which of the two sets of tests is suitable for "inbetween". Clearly the middle range pH test is not suitable for the pH 7.8 that is recommended for marine tanks, but it may be handy for other purposes.

I don't really understand why people always try to make things more difficult than it needs to be. [Of course, if API were a little more sensible, they would just make one kit, for freshwater and marine, and just mention in the documentation to not use the mid-range pH kit for marine tanks...]

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Mats

Hmmm... API makes/made a liquid "wide range" pH test kit that I don't see listed on their website. That kit's range is/was pH 5.0 - 9.0. I wonder why they stopped making it.

The one API test kit that I'm personally not that happy with is the ammonia test, as the "0" yellow and "0.25mg/l" lime green can sometimes be a nightmare to determine, comparing the test tube to the colourmetric card chart.

For me, the Nutrafin colourless "0" was always much easier to see, compared to the beige "0.25" (if I recall correctly, been using API for several months now).

Viktor Jarikov wrote: I'd recommend using a reference in your testing, at least for starters and then sporadically - e.g., do not just measure NH3 in your tank water but compare the vial to the same test of your tap water.

That's in part why I said what I said - indeed, sometimes it is hard to tell and lighting makes a big difference too. The optical properties (light absorbed, reflected, transmitted, and scattered) of a round glass vial with colored liquid and a flat piece of colored photo-paper are very different. But experience will help.