4dhk is clear? and while we're on the subject what is 4dhk??

4dkh solution is distilled water with a specific carbonate hardness of 4 degrees. 4dkh is used in drop checkers as a "control" mechanism as people's kH in their tanks varies. You can't expect consistent results with water that is not at 4dkh. The points at which the solution changes color will be different. So you are to use the 4dkh solution in conjunction with brom blue/pH indicator solution to achieve consistent results from your drop checker.

Thanks Orlando! Ok now I get it! So will I be able to pick up some bromothymol Blue at the local store? Why don't the 4dkh and the bromothymol Blue just come in the same bottle?

Mine was always green all night and closer to yellow in the mid evening turning more green once the lights were off. I made my own solution and it was acutally slightly less than 4dKH however. I just used pH indicator from my test kit for the indicator.

bromothymol Blue = ph reagent if you have a ph test kit you already have it

Dave-H said:

Why don't the 4dkh and the bromothymol Blue just come in the same bottle?

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That's a good question. It sure would simplify things a bit.

fooledyas said:

bromothymol Blue = ph reagent if you have a ph test kit you already have it

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if you have a one regent ph kit you have brom blue if you have a two part kit you don't. just a clarifier. :biggrin:

I would think if they came premixed with the reagent it would lose potency/accuracy over time. You are supposed to change out the solution in your drop checker. That schedule varies depending on who you believe.

Orlando... I have the same Waterplant Co2 drop checker and I have to agree with Dave H on the solution that comes with it being pre-mixed with 4dkh. Per your instructions I added only 4 drops of indicator solution to enough 4dkh to almost be filled to the line and the fluid inside the checker was almost clear. I do have some pure bomothymol blue from another drop checker I ordered (you were right though I like the Waterplant checker WAY better than the glass ones) and mixing 3-4 drops of that with the 4dkh solution looks correct. Is it possible that the Waterplant indicator just comes pre-mixed? I've been using it by itself and even put it along side one of the glass checkers with the other solution as a control and they both read the same.

J

Green Leaf Aquariums said:

Factory developers have mixed answers. They are developing a new model that will be available in a few weeks. Ive been mixing the dropper bottle with 4DKH with no problem strong blue every time. Are you saying your mixing the dropper bottle and 4DKH and its turning clear? How is that possible?

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I'm not sure. I'm nearly positive the dropper bottle that came with the Waterplant drop checkers comes pre-diluted. The instructions dont say anything about adding tank water or anything like that. They just say to put 1ML in the checker and put it in the tank. My other drop checker says to add 3-4 drops of reagent and fill the glass ball the rest of the way to half full with tank water (I would use 4dkh). This tells me that the Waterplants checker is ready to go straight out of the bottle.

As I posted earlier, when I only used 3-4 drops of the Waterplants indicator and fill the rest of the way with 4dkh, it is so diluted, its hard to even tell what color it is. Its really really light transparent blue. Not the nice deep blue that I get when I use the solution by itself.

J

The solution that came with the waterplant DC is pre-mixed, yea.

I bought the GLA 4dKH solution (it is clear) months ago. I use 3-4 drops of pH reagent from my Aquarium Pharmaceuticals test kit then fill my drop checker half full. I always get a nice deep blue, with a nice bright, almost yellow, green as the CO2 level goes up. Is this not the way I should be doing it?

mayanjungledog said:

I bought the GLA 4dKH solution (it is clear) months ago. I use 3-4 drops of pH reagent from my Aquarium Pharmaceuticals test kit then fill my drop checker half full. I always get a nice deep blue, with a nice bright, almost yellow, green as the CO2 level goes up. Is this not the way I should be doing it?

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Mayan... this is correct, yes.

We were just discussing that the indicator solution that comes with the Waterplant Co2 Drop Checker doesnt appear to need to be mixed with 4dkh as it comes already pre-diluted.

J

How do I know how much blue to add to the 4dhk? Tonight I reloaded the drop checker and I wasn't sure how many drops to put in - I just did it until it was dark blue like the pre-mixed fluid. Seems to be working although it's been hours and it's not reading as green as the pre-mixed fluid was!

Green Leaf Aquariums said:

Factory developers have mixed answers. They are developing a new model that will be available in a few weeks. Ive been mixing the dropper bottle with 4DKH with no problem strong blue every time. Are you saying your mixing the dropper bottle and 4DKH and its turning clear? How is that possible?

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No, we're saying you can literally take the dropper bottle and poor it into the dc and you get a reaction. As in it is 4dkh and brom blue mixed out of the bottle. I have tested it next to another dc with known 4dkh and brom blue and the reactions are identical.

No need to mix the "co2 indicator" with the ista drop checker with 4dkh solution.

Dave-H said:

How do I know how much blue to add to the 4dhk? Tonight I reloaded the drop checker and I wasn't sure how many drops to put in - I just did it until it was dark blue like the pre-mixed fluid. Seems to be working although it's been hours and it's not reading as green as the pre-mixed fluid was!

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thats how ya do it...

Seems like its reading lower than the pre-mix solution, which is strange.

hmm.. It is possible that you put a higher concentration of brom blue in which would make colors darker. This is slightly subjective.

Also, it takes some time, particularly it seems to me that fresh solutions react slightly slower. No science or proof to indicate this.