Poll Drop checker solution

[JacksonL]

Curious as to what everyone is using for drop checker solution?
A premixed commercial solution? If so, are they all pretty much the same as each other or are some better than others?
Do you DIY a 4dkh solution and add bromothymol blue? If so what is your recipe?
Do you DIY your own but make it to a different dkh ? I know some people go higher than 4 so the lime green is 40+ppm of CO2.

I am out of my DIY 4dkh solution that was made up so long ago I can’t remember when. Rather than just making more I thought I would see what others are doing.
Has anyone used a 2 drop checker system? I am thinking I may run a low dkh checker so it turns full yellow at 30ppm to give a floor reading and a higher dkh solution that turns green at 45ppm.

 

[Naturescapes_Rocco]

I make my own!

4dKH Indicator Solution

Need:

• NaHCO3 (Baking Soda)
• 0.04% BTB
• 1L Graduated Cylinder
• Small Scale
• Micro Scale
• 5-10mL Syringe
• Storage Bottle

1. Dissolve 0.12g Sodium Bicarbonate (NaHCO3, Baking Soda) into 1,000mL RO water (I use a milligram scale)
2. Tare storage bottle weight, and add 40g of this 4dKH solution into bottle
3. Add 5mL Bromothymol Blue 0.04%
4. Store in a cool, dark place.

If you don't have a milligram scale, you can make a 40dKH solution first, then dilute it to 4dKH.