What chemicals / concentrations are used for standard test kits?

[dtruitt]

I'm a controls engineer by day, so I've been musing about making a DIY Trident / Reefbot automated test system in my spare time.

My willingness to embark on such a project is dependent on the availability of affordable reagents, and preferably reagents that dont need to be vigorously shaken before use.

I would have to imagine that many of these test reagents are fairly ordinary solutions that can be purchased at significantly lower cost when they arent labeled for aquarium testing purposes.

Any recommendations for where I can go to find this sort of info?

 

[dtruitt]

I've been looking at SDS on test kit manufacturer websites. The information contained within seems to provide a good way to narrow down internet searches.

So far I've identified a good article that describes the process the API Calcium test uses in substantial detail. It would appear that this process is easily modified for testing hardness and magnesium. The reagents listed appear to be accessible and affordable enough to promise significant savings if conducting 4+ tests a day.

Determining Calcium Ion Concentration in Water Chemistry Tutorial

Determining the concentration of calcium ions in water using complexometric titration with EDTA tutorial suitable for chemistry students

www.ausetute.com.au

pH testing is a common enough process that it's easy to find information on the matter.

I will need to look into Alk, Nitrate, and Ammonia in more depth.

It seems like nitrite is a non issue once a tank has cycled unless something crazy happens.

Any other tests that I should think about if I want to tackle such a project for personal use?

 

[dtruitt]

Ammonia test: https://www.google.com/url?sa=t&sou...FjAGegQIBxAB&usg=AOvVaw1tONAqDCfTIRT6VgCWhiDF

Alternate ammonia test: https://www.google.com/url?sa=t&sou...FjAFegQIAhAB&usg=AOvVaw2H4M9rRrYTrvtFaQtsqnbW

 

[taricha]

A good place to start might be the hanna instruments site.
for each checker, they list a publicly available chemical method that their test kit is based on...
For instance, the phosphate ULR lists
"Method: adaptation of the Standard Methods for the Examination of Water and Wastewater, 20th edition, Ascorbic-Acid method"
a quick google and voila: all the gory details.
https://www.standardmethods.org/doi/10.2105/SMWW.2882.093

If on the other hand, you want to work out the exact contents of reagant A, B and C etc. for various test kits, that's harder and maybe not possible.

 

[StatelineReefer]

MSDS Archives - Red Sea

www.redseafish.com

exact contents.

Material Safety Data Sheets are your friends.

Unfortunately this reagent style does require shaking or stirring. A mag-stirrer can be incorporated inexpensively, if you know how to build one.

Your most common tests will always be alkalinity, nitrate, and phosphate, in my experience, followed by calcium and magnesium if you grow stony corals.

Ammonia should be a tertiary concern unless you anticipate something's cryptic demise.

 

[Dan_P]

I'm a controls engineer by day, so I've been musing about making a DIY Trident / Reefbot automated test system in my spare time.

My willingness to embark on such a project is dependent on the availability of affordable reagents, and preferably reagents that dont need to be vigorously shaken before use.

I would have to imagine that many of these test reagents are fairly ordinary solutions that can be purchased at significantly lower cost when they arent labeled for aquarium testing purposes.

Any recommendations for where I can go to find this sort of info?

Great project idea. Sounds like fun.

I see you are getting good leads so I will just mention that the nitrate test has been automated and the “vigorous shaking” replaced with a column of small cadmium particles. I think you will find that all tests are possible without vigorous shaking.

The shelf life of reagent solutions and ways to extend them will be an area to consider before automating a test. How corrosive a reagent is will guide your selection for the material of construction of parts that are wetted by these reagents.

Just for fun, consider buiding a machine that uses already available test kits.

 

[dtruitt]

Great project idea. Sounds like fun.

I see you are getting good leads so I will just mention that the nitrate test has been automated and the “vigorous shaking” replaced with a column of small cadmium particles. I think you will find that all tests are possible without vigorous shaking.

The shelf life of reagent solutions and ways to extend them will be an area to consider before automating a test. How corrosive a reagent is will guide your selection for the material of construction of parts that are wetted by these reagents.

Just for fun, consider buiding a machine that uses already available test kits.

I think starting with off the shelf testers is wise. Nonetheless, if I understand the specifics of these tests a little better, I can eliminate some additional hardware.

Ca, Mg, and Hardness can all be calculated with just two reagents and two tests, for example. I very much suspect the API tests specifically for those parameters could be consolidated. This would cut down on costs for parts.

I'm imagining a syringe based system. I think some PE tubing with check valves and self healing rubber caps could be used to minimize the length of the required linear actuator. This would also allow the reagents to live outside of an enclosure, away from the electronics, where they can be more easily replaced.

The test vessel I have in mind is a plastic cuvette. Glass apparently can react with many reagents used for these tests (more so than plastic, oddly enough).

My biggest concern is actually rinsing and emptying the vessel between uses. I'd prefer to do that without using a motor to flip the vessel, or wasting tons of water, if possible.

 

[dtruitt]

MSDS Archives - Red Sea

www.redseafish.com

exact contents.

Material Safety Data Sheets are your friends.

Unfortunately this reagent style does require shaking or stirring. A mag-stirrer can be incorporated inexpensively, if you know how to build one.

Your most common tests will always be alkalinity, nitrate, and phosphate, in my experience, followed by calcium and magnesium if you grow stony corals.

Ammonia should be a tertiary concern unless you anticipate something's cryptic demise.

How do you think sucking a mixture into, and forcing that mixture out of, a syringe would work in place of a stir bar? I intend to keep the testing vessel very small to conserve reagent and allow for more tests per day.

 

[dtruitt]

So to summarize the info so far:

Salinity - Probe
pH - Probe
KH - Sulfuric Acid titration process, using pH probe to measure when the solution reaches 4.5
Hardness - EDTA titration
Ca - Precipitate Mg out of solution, then EDTA titration
Mg - Hardness - Ca

This just leaves nitrate and phosphate. To be honest, we don't do water changes and nitrate and phosphate are at 0 because we run chaeto. I'm happy to manually test those parameters when something looks off.

The intent behind this project is to allow us to add lots of stony coral without lots of testing.

 

[redvsblue23]

I'm a controls engineer by day, so I've been musing about making a DIY Trident / Reefbot automated test system in my spare time.

My willingness to embark on such a project is dependent on the availability of affordable reagents, and preferably reagents that dont need to be vigorously shaken before use.

I would have to imagine that many of these test reagents are fairly ordinary solutions that can be purchased at significantly lower cost when they arent labeled for aquarium testing purposes.

Any recommendations for where I can go to find this sort of info?

We have a photo-spectrometer at our family soap factory, I’ve been wanting to have our chemist analyze some supplements and reef salt for me but I don’t know if it would work lol

 

[Randy Holmes-Farley]

I’d be wary of generalizing concentrations as there no reason to assume two different kits use similar concentrations of reagents.

 

[dtruitt]

I’d be wary of generalizing concentrations as there no reason to assume two different kits use similar concentrations of reagents.

That's a good point. I suppose I was generally hoping to know if there is a "generic" equivalent for specific tests.

Looking on amazon, its drastically cheaper to buy reagent in bulk that isnt labeled for aquarium use.

I have been looking at articles on your website, and I think a lot of the information you've made publicly available will be of considerable help in this endeavor. Thanks for what you do!

 

[JimWelsh]

@dtruitt thanks for this thread. I needed a good laugh today!