[Rusty Shackelford]

I want to get a low cost drop checker for my 155g tank however unless you're willing to pay a lot for a checker + solution the reviews on them are not good. Is there any reason why I can't buy a cheap drop checker, a bottle of Bromothymol blue, and make my own 4dKH? Bromothymol blue is quite cheap in a .04% solution but I can't find much about it being used or if that's the correct concentration.

 

[Mike A.]

I'm an aquarium CO2 newb but have background otherwise. Don't think that there's any specific concentration required for the indicator. It's fairly strong stuff as far as coloring a solution. .04% should be fine. Stronger would be darker (obviously). If too dark you could always dilute as needed. Just a difference of how many drops you'd add in final solution. In either case not sure how much you'd save but you'd have a lifetime supply in a single small bottle.

I got one recently with the glass, 4dKH solution, and extra indicator for like $12 on Amazon. Then just bought some cheap with glass only. Not sure how useful they are longer term but just going in I wanted some easy reference and as a double-check to my pH measurement while testing things. Too many individual smaller tanks in my case but with a larger tank a controller probably makes a lot of sense.

 

[kgbudge]

I made up my 4 dKH solution after measuring my well-aerated tap water at 6 dK, by mixing it 2:1 with deionized water. Then I checked to verify it was now 4 dKH.


What I want to know is how to clean the drop checker bulb. Mine has acquired some kind of film inside the bulb, and even a wash in concentrated HCl didn't remove it.

 

[Edward]

What I want to know is how to clean the drop checker bulb.

For the glass Clorox, Javex, Bleach.

Rusty Shackelford
You can use 2L Coke bottle, fill it with distilled or RO water and add 0.24 grams of baking soda NaHCO3 to make 4 dKH solution. Fill the drop checker and add two drops of pH reagent.

 

[yusufsarac]

I'm very interested in this. I have opened another thread a couple days ago here: https://www.plantedtank.net/forums/20-diy/1288339-making-own-4dkh-ph-indicator-all-diy.html

Maybe we can come up with another formula that works with red cabbage instead of Bromothymol blue and make it completely diy.

 

[Darkblade48]

I made up my 4 dKH solution after measuring my well-aerated tap water at 6 dK, by mixing it 2:1 with deionized water. Then I checked to verify it was now 4 dKH.

The problem with using tap water is that there may be other factors (such as phosphates) that may influence the pH. This is why a solution of deionized water where the only influencing species is carbonate is ideal for a reference solution.

 

[kgbudge]

I know my tap water's chemistry pretty well, so I'm pretty safe using it this way. Your mileage may vary.

 

[Chlorophile]

If you look back at my old journals you'll see I have had some pretty bad bad algae before.
The best thing I ever did was get rid of my drop checker.

If you make the solution right you're limiting yourself.

I moved houses and lost my solution so when I set the tank back up I just turned co2 up every day.
One day I noticed fish look stressed, so did 50% water change and turned co2 down a hair.
Now it's perfect, I don't get BBA anymore either.
Ph goes from 8.2 to 6.2-6.4 depending on my water level in take and surface agitation.