# Bromo Blue and 4 dKH



## Will (Jul 24, 2008)

Hello errybody.

I recently received some new drop checkers and 4dKH solution (Orange solution). It did not come premixed with bromo blue. So I have two questions...

Where can I find a cheap/local source for bromo blue? Is there somewhere that sells the premixed solution affordably? I'll be using it in 4-7 drop checkers soon, so I ought to have some on hand since the bottle of only 4dKH I have it rather small.

I'll be heading to the pharmacy today to price bromo there. I've heared it's pricey.

Any and all suggestions on the matter are appreciated.

Looking back at the auction page it says to 

----
Instruction
Turn drop checker up-side-down and place 3-5 drop of test solution into the drop checker.
Use a pipette (not include) to inject tank water into the drop checker.
You will see the color change on the solution according to Co2 content in the tank water.
Turn drop checker up-side-down again carefully, and place the drop checker inside the tank below water level.
----

Seems a bit vague. How much water to add? So no bromo blue is needed with this orange solution provided? This does not seem to be the typical intrustions for the liquids inserted into the drop checker, why does it say to add tank water at all?


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## Will (Jul 24, 2008)

So I guess i got it working now... by just following the instructions provided...










What is the difference between using this Orange solution shown here (5drops), mixed into some tank water...

... than the method where you use a 4dKH solution, and add in some bromo blue, without any tank water mixed in?

Seems entirely different?


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## charlie1 (Dec 1, 2011)

Will said:


> So I guess i got it working now... by just following the instructions provided...
> 
> 
> 
> ...


I have no experience with that solution you got.
But he 4 DKH standard & Bromo( PH testing reagent) is the common /popular one around.
The 4DKH is pure & calibrated carbonated solution, tank water carbonate can be influenced by other sources in the tank & thus provide a false reading.
There is well written piece on the 4 DKH -5DKH method by a guy named Hoppy over on Barrreport & another forum he frequents, if find it later i will link it.
Hope that helps


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## df001 (Nov 13, 2007)

bromo blue = standard PH test reagent (if you have the API ph test just use a few drops of that, i usually use 2-3,

my issue with the included reagent is - not knowing what it is, how its chemistry works - how do you know if its accurate - using your tank water which has a variable ph, variable d KH, there's no way to know if you're in the target range for co2 PPM

by using the 4DK - you know your color change is as accurate as your 4DK solution is.

4DK is stupidly easy to make if you have an accurate scale - what I did was make some 200 KH water, which I then add 10ML to 490 ML of distilled water to make 500ML of 4dk - which should last you a good long time.

feel free to ask any questions, or if you're close by and want to pop over, I can hook you up with some if you're willing to pay it forward when you can.


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## Will (Jul 24, 2008)

Thats very generous of you, however I never get out to East York, let alone almost never to my Mississauga fish store route.

And thanks for the info, (also I do have API ph tests, both FW and SW), but now *I'm really wondering what exactly is the orange co2 test regent* I've got here... It's orange, but turns blue or green when added into water. I've had it in the tank for a couple hours now and it's still green, so I'll post back late tonight or tomorrow with an update.


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## wesignup (Apr 24, 2008)

Not to divert this thread....The 10ml bottle looks like its from UP Aqua. The orange agent is a combination of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue).

I was told by the ebay seller to add a few drops to the drop checker and wait for few a hours and see the color change. He mentioned not to add any water to it as it already pre-mixed. 

Please advise if this is true?


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## Will (Jul 24, 2008)

wesignup said:


> Not to divert this thread....The 10ml bottle looks like its from UP Aqua. The orange agent is a combination of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue).
> 
> I was told by the ebay seller to add a few drops to the drop checker and wait for few a hours and see the color change. He mentioned not to add any water to it as it already pre-mixed.
> 
> Please advise if this is true?


I bought this from "Aquarium HK" on ebay.

The ebay ad reads:

Instruction
 Turn drop checker up-side-down and place *3-5 *drop of test solution into the drop checker.
 Use a pipette (not include) to inject tank water into the drop checker.
 You will see the color change on the solution according to Co2 content in the tank water.
 Turn drop checker up-side-down again carefully, and place the drop checker inside the tank below water level. 
The label on the back of the bottle reads:

Add 5 drops to the water in the drop checker

When I added only the Orange Co2 regent to the drop checker, it remains orange. Even overnight when my co2 runs still, and lowers the ph.
When added tot he aquarium water it changed from orange to blue to green as I added the drops in.


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## wesignup (Apr 24, 2008)

Strange I was told the opposite not to add aquarium water....I haven't tested it out yet. Just to confirm did you use aquarium water or regular tap water? How many drops did you add?


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## Will (Jul 24, 2008)

As per the instructions provided, I used *tank water*, added in *5 drops* of the reagent.


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## charlie1 (Dec 1, 2011)

wesignup said:


> Not to divert this thread....The 10ml bottle looks like its from UP Aqua. The orange agent is a combination of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue).
> 
> I was told by the ebay seller to add a few drops to the drop checker and wait for few a hours and see the color change. He mentioned not to add any water to it as it already pre-mixed.
> 
> Please advise if this is true?


 The link Will posted say exactly what he qouted, but another seller has this


> Maintaining proper Carbon Dioxide (CO2) levels in the planted aquarium is one of the most important factors in the health of the planted aquarium ecosystem. A CO2 drop checker is an essential tool for monitoring CO2 levels in the aquarium. The CO2 drop checker is a reservoir designed to contain an indicator solution and an airspace. *The indicator solution is a combination of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue). **When the drop checker is submerged in the aquarium, the carbon dioxide will outgas from the aquarium water into the airspace of the drop checker and will eventually be absorbed into the indicator solution. The carbon dioxide gas will seek a point of equilibrium between the indicator solution and the aquarium water. As equilibrium is achieved, the color of the indicator solution inside of the drop checker will change based on the concentration of CO2 in the aquarium water. *If the indicator solution is green in color, then appropriate levels of carbon dioxide exist in the aquarium, and no action is required. If the solution in the drop checker changes to blue or yellow, then the CO2 levels in the aquarium are too low or too high, respectively.


 What this seller posted makes perfect sense if the solution is made up the way he described.
http://www.ebay.com/itm/CO2-Drop-Ch...995?pt=LH_DefaultDomain_0&hash=item3a62b7e8b3


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## wesignup (Apr 24, 2008)

Thanks charlie1 - Still little confused....does it still mean we have to mix aquarium water in the drop checker + the solution of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue)?


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## df001 (Nov 13, 2007)

wesignup said:


> Thanks charlie1 - Still little confused....does it still mean we have to mix aquarium water in the drop checker + the solution of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue)?


No, mixing your aquarium water + 4dKH would give you an solution of unknown KH and PH

the whole point of mixing 4dKH as accurately as possible, is that it gives you a known reference point with respect to the color of the PH reagent.

Maybe its time someone with some time on his hands should do a write-up on it....


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## charlie1 (Dec 1, 2011)

wesignup said:


> Thanks charlie1 - Still little confused....does it still mean we have to mix aquarium water in the drop checker + the solution of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue)?


I would follow the instructions you received with your drop checker, if what the seller states is accurate


> The indicator solution is a combination of KH Standard / 4 degree KH (4 dKH) and pH indicator (Bromothymol Blue).


 what he has done is pre mixed the 4 DKH & the indicator reagent so no need to add anything else.
Regards


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## Will (Jul 24, 2008)

Both instructions I received state to mix the orange solution (4 dKH + Bromothymol Blue) into tank water in the drop checker...


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## coldmantis (Apr 5, 2010)

Will,

do the following:
take that green bottle in your right hand, go to the garbage and drop it in
go get a ph test kit, walmart sells it for like 5 bucks
while your in walmart go to the grocery section and get a bottle of 4L distilled water and a box of baking soda
on your way home either stop by a flea market or something and try to find a digital scale that's at least 0.00g accurate(if you can't find it then back to ebay)
go home and search for darkblade's post on how to make the 4dkh solution
once that is made turn your drop checker upside down, put like 4-5 drops of the ph test kit solution in it
next get a syringe(buy at walmart pharmacy if you don't have one) suck up some 4dkh solution maybe around 3-4ml and squirt it in the drop checker until it's around 75% full
put in your tank and wait 2-4 hours

why should you throw away that green bottle? I used to use that and got bba all the time even though I used 4dkh solution with that green bottle and my drop checker was always yellow, I was running 1 bubble per 3 secs!!!! on a 45 gallon tall!!! after I threw that green bottle away and used some api ph solution my drop checker was always dark blue unless I bump the bubble rate to 1bps or more.

Jimmy


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## Greg_o (Mar 4, 2010)

coldmantis said:


> Will,
> 
> do the following:
> take that green bottle in your right hand, go to the garbage and drop it in


Awesome.

If you have the time and means I would recommend this as well.

Even better,

Set one drop checker up as described in the instructions with tank water, and second drop checker with 4 dKh and bromo blue. Put them side by side in a tank and let us know what (if any) difference in colour you observe.

I can give you some 4 dKh if you want if we can meet up, or mail it you if need be.


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## wesignup (Apr 24, 2008)

Great info' Jimmy! I might try that myself....making my own solution.


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## df001 (Nov 13, 2007)

Here's an article that explains it really well: specifically the section about buffers.

http://www.njagc.net/articles/co2dropchecker.htm

As for making 4dkh, what I found to work easiest for me was to make a 200dkh solution by disolving 6 grams of baking soda into 1L of distilled water.

(use a scale measure as accurately a possible, same with the water - use a graduated cylinder etc)

then 10ml of the 200dKH into 490ml of distilled water will give you 4dKH.

I change my drop checker when it gets dirty/algae etc. 3 drops of ph reagent, then a few ml of 4dKH till the drop checker is 3/4 full.


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## Will (Jul 24, 2008)

It seems that the green bottle is working so far. I will keep watch for BGA. I've had it before, but it went away when I adjusted the KNO3 dose amount.

I don't mind tying out both solutions side by side... who will mail a bottle...  

I already have the API PH test (bromo blue right?).
Thanks for all the advice and info on this matter.


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