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CO2 measurement / checking drop checker

2244 Views 2 Replies 3 Participants Last post by  Hoppy
***see pictures below***

I have been using one of the knock off drop checkers I bought from Asia for the last couple of months. It makes me feel like I have a little more control of my CO2. The only thing is that when I compare the bulb color with the pH chart it still leaves room for error on my part.

To get a better feel of what the pH was of each color, I came up with the following device. I don’t plan on leaving this in my tank forever, I was just using it long enough to make sure it worked and to have a more accurate idea of what the pH was of each color in my drop checker bulb.

About 3 weeks ago I was at a craft store with my wife and I picked up these parts for about $6.

  • The bottom container holding the pH standard (mine is 5 dKH)
  • The top dome providing an air pocket over the bottom container.
  • One pack of clear suction cups (used to hang things on windows)
  • One pack of clear body ballpoint pins (came from a dollar store)
  • Super glue (also came from the dollar store)
  • A couple of misc. suction cups (I had in my aquarium spare parts.)

To assemble:

  • I removed the ink cartridge from the pen
  • cut off both ends of the pin
  • removed the metal hooks from the suction cups
  • trim the ends of the suction cups so they fit in the pin body
  • superglue the suction cup to the pin body
  • attach the double ended suction piece to the bottom container
  • fill the bottom container ¾ way full of a KH standard water
  • wet the top suction cup and attach the top dome
  • submerge into aquarium and attach to the wall using misc. suction cups

What I did was pretty much just like the drop checker. I put a 5 dKH standard of distilled water in the bottom container and when I wanted to know the actual CO2 I would pull it out of the water and put my pH meter in the bottom container and measure the pH. When done I would put it back in the tank for the next reading. This has helped me feel more comfortable about my drop checker and what each small amount of color change means. It was kind of big because it had to be big enough to fit my Hanna pH meter in. I had it in my 120 tank and the whole thing was clear so it wasn’t to bad. This could be made in many shapes and sizes depending on your meter.



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Does the bottom float within the top? Or put another way, is the top attached to the bottom in any way? Doh, suction it.

Nice work!
Now that is a neat idea! Even if you don't use the pH probe in it, it is an easy way to assemble a drop checker.
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