# Drop Checker Indicator Color (Clear)?



## mkeevil (Oct 22, 2006)

I purchased a Double Check CO2 Checker and installed it yesterday, the instructions say if the color is more blue then you don't have enough CO2... and if the color is more Yellow then you have too much CO2.. the color of the indicator solution is clear in my tank... it looks like there is no pigment at all? Has anyone seen this before, am I installing it wrong and getting tank water in there?


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## Seattle_Aquarist (Mar 7, 2008)

Hi mkeevil,

How many drops of indicator solution did you add to your drop checker? After filling mine about 1/2 full with 4 KH water I add about 4 drops of indicator solution. At that time my solution is a definite blue. Flip it over, submerge making sure there is air in the "neck" of the checker, install about 1/2 down the height of my tank away from my CO2 source.

If it wasn't blue when you added your indicator solution, then I would suspect the solution. If it was blue but faded after you put it in the tank, I would guess tank water is getting into the chamber.


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## HeyPK (Jan 23, 2004)

The indicator, bromthymol blue, goes from blue through green to yellow as you get more acidic. It never is clear. It must have been washed away.


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## kimcadmus (Nov 23, 2008)

I don't have personal experience with drop checkers but I believe I remember clear indicating alot of CO2. 

I think I remember Texgal saying she turned her CO2 up to turn the DC clear. Texgal?


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## mkeevil (Oct 22, 2006)

I filled the chamber about 1/2 way full... and it was blue when I put it in the tank.. and has gone clear. I just got back from the fish store, purchased a CO2 test kit. I used 8 drops in the test kit which would be 16ppm... if I read it right. So I guess why question now is what is the best ppm for a planted aquarium... I'm going to go off of the test kit for now, and just keep my eye on the Drop checker.


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## orlando (Feb 14, 2007)

What I would do is remove the drop checker and place on the outside of the tank.
Then check back in a few hours to see if the color changes back to blue. This way you can see if its working properly and not some strange malfunction of the reagent or DC itself.

Regards, O


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## mkeevil (Oct 22, 2006)

I took the drop checker out, and let it sit attached to the outside of the aquarium... and it turned blue.


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## HeyPK (Jan 23, 2004)

Ok. That means that the bromthymol blue was still there and you probably had only a little of the dye in the solution. It didn't really turn clear, but a very light yellow in the tank. The blue color is much more easily seen at low dye concentrations than the yellow color. Put a few more drops of dye in and return the drop checker to the tank. You should aim for a green color. Yellow means too high a level, and your fish may be stressed.


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## mkeevil (Oct 22, 2006)

So I think the problem is with the color of my tank/water... it aways looks clear. I took a white piece of plastic and stuck it in the tank... and I can see that it's a light blue... so I think the dye is not dark enough or blending into the tank. It seems to be working fine, but when I want to determine what color it is, I have to put a piece of white behind it so the color shows clear.


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## HeyPK (Jan 23, 2004)

You need to have a higher concentration of the indicator dye.


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## gibmaker (Jan 3, 2007)

That happens to me also. I add more than 4 drops of ph reagent and after about a week it slowly turns clear, the whole while being green and becoming more and more transparent until it is clear. My solution is pretty much opaque by the time I put the drop checker in the aquarium. I thought of the possibility of my bright lights bleaching out the color in the drop checker? I keep my drop checker 3/4 of the way up the glass on the opposite side of my co2 reactor, so it is kind of close to the lights????? I can't come up with anything else because I know that tank water never gets in it???? I did a w/c last night and moved my drop checker further away from the lights so it isn't getting directly blasted by them, well see what happens.

Just offering more ideas, for I have the same problem.


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## HeyPK (Jan 23, 2004)

Could the indicator somehow be escaping into the aquarium water? The idea of a drop checker is to keep the indicator solution isolated and out of contact with the tank water. The CO2 diffuses from the tank water into the air in the chamber and then from the air into the little cup of the pH indicator solution.


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## SniperLk (May 25, 2008)

I think HeyPK is right... I'm using a DC and the reagent is still opaque a month later.


PS : my DC is just under the lights too


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## gibmaker (Jan 3, 2007)

My indicator solution does not get introduced into the aquarium or the other way around. I don't even see how that could happen. It is hard enough to fill the thing while holding it in your hand much less having the water escape or find it's way into the drop checker.


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## dannyfish (Sep 7, 2006)

i just bought a co2 checker

Please advise me is this how to use this devise, thank?
Drop 3-4drop of the solution given and some tank water into it and turn upside down and let the water go into the ball half filled.

Now the colour show "Blue" - represent not enough co2

the step where i put the solution is it correct?


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## bosmahe1 (May 14, 2005)

dannyfish said:


> i just bought a co2 checker
> 
> Please advise me is this how to use this devise, thank?
> Drop 3-4drop of the solution given and some tank water into it and turn upside down and let the water go into the ball half filled.
> ...


You don't want to use tank water, you want to use 4KDH water. That way a green color corresponds to 30 ppm CO2. There are other things in your tank water besides carbonates that can alter the results, phosphates for instance.

http://www.greenleafaquariums.com/co2-drop-checkers/kh-standard.html

250 ml will last you quite awhile.


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## CRS Fan (Nov 25, 2008)

I have seen the indicator solution go clear in a tank once. This guy was pumping in Co2 like a madman. I think his CO2 was in excess of 50ppm and all his fish were gasping and playing dead on the bottom . There was no way of counting BPS because his bubble count was like a rolling boil. I do not suggest this approach. Mind you he had very healthy plants. Typically a clear solution could indicate not enough or poor quality indicator solution. Please also ensure you are using a 4DKH as the test solution for accuracy.


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## HeyPK (Jan 23, 2004)

When the color indicator, bromthymol blue, is all converted over into the yellow form at the lower pH, the yellow color is less intense than the blue color is when it is all converted over to the blue form at the higher pH. If you have a dilute solution of the color indicator, you will be able to see the blue clearly, but the yellow may be so faint that the solution looks clear.


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## Tex Gal (Nov 1, 2007)

I've had my d/c water turn yellow. It's only gone clear when it's been contaminated with tank water. I do think you can have bad indicator fluid. I also think it can get old somehow. That's why you are supposed to change it ever so often. ...otherwise we'd never have to change the thing...


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