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cypho edited this page Feb 28, 2018 · 18 revisions

The products/vendors listed below are the sources I used. Most of these items could be found from different vendors or replaced with slightly different products.

AliExpress

4 pumps are needed for Alkalinity. An additional 3 are needed for Calcium. And one more is needed for Magnesium. I stopped at 8, but you may want to add another 3-4 pumps, so you can dose Alk, Ca, and Mg supplements based on the test results.

Order extra connectors because they are easy to break and it is hard to find replacements. The pump is designed to use Kamoer's 3/32 connectors. Even though the tubing is 1/16, the 1/16 connectors do not fit the pump. This apparently even confuses Kamoer. In one of my orders they included a few extra 1/16 connectors for free. That would have been wonderful aside from the fact the 1/16 connectors don't fit the pump.

NOTE - I have not finished building the Calcium and Magnesium tests so I am not yet sure that portion of the project works.

Sparky's Widgets

None of Sparky's stuff is ever listed as "in stock". Go ahead and order it and be prepared to wait a long time for sparky to assemble the parts. Although there are other pH boards that you could order without the wait, I think these are worth the wait.

Bulk Reef Supply

This is probably not the best probe, but I know this one works. My pinpoint probe has been in service for over a year and is still working very well. However if a faster reacting probe can be found, that would be a very nice improvement.

Adafruit

Each Trinket will command 2 peristaltic pumps.

Color sensor is only used for the Calcium and Magnesium tests. If you only plan to do Alkalinity, you can leave this out. I have not actually tried the Ca or Mg tests yet, so I am not yet positive this part will do what we need it to.

Sparkfun

You need one Big Easy Driver and one heatsink per peristaltic pump.

Raspberry Pi Zero is plenty powerful, but if I were to do it over I might go with the full sized Pi because it has an ethernet jack. Wifi works but was more difficult may be less reliable than a wired connection.

ServoCity

I used a longer piece of Mini-Channel and cut it down 1.54" when I found the piece I ordered to be too long. The 1.54" should be perfect as is.

I used the 2600 RPM motor not knowing what speed would be best. It does work, but a different motor might work be better. I am driving it at the lowest speed I can without the motor stalling, so a slower motor may be better. The stirrer is the noisiest component in my build; a different motor might be quieter.

Amazon

Chemicals for Alkalinity Test

Using 0.1N HCl instead of 0.01N HCl reduces the cost of reagents dramatically (they cost the same but you get 10x as many tests out of a bottle of 0.1N) but it also magnifies the impact of any errors delivering the acid by 10x.

I have used both acid strengths and both produced acceptable results. I have not decided yet which I will use long term.

Chemicals for Calcium Test

I originally tried a 0.1M NaOH solution. That was not strong enough. 1M is needed. Unlike the HCl and EDTA, you don't need to know the strength of the NaOH solution with any precision, so you can mix your own NaOH solution from solid NaOH pellets.

I am not sure if 0.01M is an appropriate concentration for the EDTA, but that seems to be the most common strength so that is what I am going to start with.

Chemicals for Magnesium Test

  • All of the chemicals in the Calcium Test section.
  • Calmagite

You can do Ca test without doing Mg, but you need all of the supplies for the Ca test to do the Mg test. This is because the Mg titration is actually measuring Ca + Mg. To determine the Mg you have to also do the Ca titration so you can subtract the result from the Mg+Ca titration.

NOTE: The chemicals above are what I plan to use for Ca and Mg, but I have not actually confirmed the Ca and Mg tests work.

Ebay

  • 10x 1/4"x1/8" N52 Neodymium Disc Magnets
  • BIPEE 7pcs Octagon PTFE Magnetic Stirrer Mixer Stir Bars White Color
  • Generic DC Barrel Jack 5.5x2.1mm 12V Panel Mount for Wall Supplies
  • Rubber Grommets 3/16" Inner Diameter Fits 5/16" panel hole 1/4" Groove
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