Most accurate manual test kits?

[Reefnman2]

I've been using the API test kits for a few months but while reading this forum I see they may not be the best, so I am wondering what others use and consider the most accurate?

 

[Chefwheredyougo]

I personally use Red Sea. Its alot easier to see the color difference than api. Theres also Salifert and Hannah that are pretty big

 

[Billdogg]

I am a huge fan of the Salifert test kits. They are very easy to use and give very consistent, repeatable results. They are also pretty reasonably priced.

 

[Bayareareefer18]

I use red sea for ca and mag. I found the red sea alk a little tough to decide the point of color change. Salifert alk was much easier. Now I use hanna dkh checker and the po4 checker. They are a little pricey but I find I test way more with them being so easy

 

[C. Eymann]

For Alk/cal/mag I prefer Salifert, for NO3 and PO4 I prefer RedSea or Hanna (PO4)

 

[Reefnman2]

I personally use Red Sea. Its alot easier to see the color difference than api. Theres also Salifert and Hannah that are pretty big

Yes that's the problem I have with API, hard to interpret the colors at times.

 

[Chefwheredyougo]

I find it very accurate. But.. there is more to it than just adding a few drops.

 

[EMeyer]

I will say after examining several test kits using a spectrophotometer that I think most of the chemistry in hobbyist test kits is fine. The problem usually lies in the details of how theyre used (including typically the instructions).

Most of these tests are "colorimetric"; based on absorbance of a particular wavelength of light by the compound of interest. Which is a perfectly fine way to measure concentrations. But a real, lab-based analysis using the same chemistry would include three things hobbyists typically dont:
1. an objective measurement of color (as hobbyists we do this subjectively)
2. a blank
3. at least one standard, preferably more

Outside of buying a spectrophotometer we can't do much about #1. But there's nothing stopping us from including blanks and standards in our water tests. I bet a lot of the complaints about hobbyist test kit accuracy would go away as a result.

 

[C. Eymann]

Yeah Red Seas color wheel is especially helpful in determining NO3 and PO4, takes the guess work out of "what shade is that"?

 

[BeejReef]

Bulk Reef Supply sells a standard that covers most commonly tested parameters

Saltwater Multi Reference Solution

The only reference solution based on a saltwater matrix that includes 8 of the most popular parameters for saltwater aquariums in a single solution. Fauna Marin’s Multi-Reference Solution is used to check your home water test kits for accuracy. Using your water test kits at home, you can measure...

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It helped me to determine what point I should call it good on a lot of the titrations and color-centric tests.

I use hannah for phosphate
Salifert for Nitrate
RS and Hannah for alkalinity
RS for calcium
RS for magnesium (contemplating a switch)
Salifert for PH, Ammonia, Nitrate

Any and all of them have given crazy readings now and again. Don't trust them on a day to day basis.
A practiced, repeatable, and cleanly approach really makes a big difference.