# What colour drop checker?



## Cro (20 Jun 2009)

I have just received a glass drop checker (like a Boyu but from eBay) and as there isn't any instructions I need to know what colour it should be for good Co2, Green, Blue or Yellow?

Cheers

Alex


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## Dolly Sprint 16v (20 Jun 2009)

Cro said:
			
		

> I have just received a glass drop checker (like a Boyu but from eBay) and as there isn't any instructions I need to know what colour it should be for good Co2, Green, Blue or Yellow?
> 
> Cheers
> 
> Alex



Alex

Blue No Co2 in water column

Green is good

Lime Green is even better

Yellow - Dangerous too much Co2 in water column.

Regards
paul.


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## samc (20 Jun 2009)

lime green is what to aim for


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## glenn (20 Jun 2009)

Flyfisherman said:
			
		

> Blue No Co2 in water column
> 
> Green is good
> 
> ...


but if you have no fish or invertibrates go for yellow so you no for shure there is no deficiency of co2.


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## Cro (20 Jun 2009)

TYVM everyone.


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## ceg4048 (20 Jun 2009)

Hi,
    You would do well to study this article:> CO2 Measurement Using A Drop Checker

Cheers,


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## Cro (23 Jun 2009)

I can't work out what I'm doing wrong. My old JBL drop checker always showed the correct colour, but now I have this glass one it's always yellow. I've had the Co2 off for 36 hours now so it has to be wrong, anyone have any ideas?


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## Cro (23 Jun 2009)

I have just taken out the drop checker, given it a quick clean (with RO water only) and have refilled it with 1.5ml RO water and 4 drops of reagent, this is the colour it goes straight away and turns more of a yellow after being in the tank for a while.






I know using 4dkh solution is better than RO water but the missus is moaning about spending at present so it has to be RO for now.


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## aaronnorth (23 Jun 2009)

RO is pointless unless you know the KH of it. As is any solution. 
if you cant afford 4dkh, then just watch plant growth & fish reactions.


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## ceg4048 (23 Jun 2009)

Are you using 4 dkh water?
If so did the mixture turn yellow immediately?
Measure the KH of your 4dKH water to ensure that it is in fact 4. If it is lower than 4 then return it to the vendor.
Using RO water is worse than pointless. Please read the article I gave the link to.

Other possibilities:
Have you washed the dropchecker with anything acidic, like vinegar for example?
Test the pH of some other water like your tank water or tap water using the same indicator reagent. It could be duff.

Cheers,


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## Cro (23 Jun 2009)

aaronnorth said:
			
		

> RO is pointless unless you know the KH of it. As is any solution.
> if you cant afford 4dkh, then just watch plant growth & fish reactions.


KH is approx 20 (just checked it with test strip)


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## chris1004 (23 Jun 2009)

Cro said:
			
		

> I know using 4dkh solution is better than RO water but the missus is moaning about spending at present so it has to be RO for now.



Hi Cro, 

Do what I do mate and don't tell her.    

You have to have a referance solution in the drop checker or it won't work, simple as that really. 4KH has just become the recomended norm but as long as you know what you have in the DC then its posible to use it but the referance colour that your trying to achieve will be different due to the PH/KH/CO2 relationship. RO water doesn't have any KH at all so it can't work.

Seriously though if your a bit stuck you can make your own 4kh solution if you have a kh test kit, RO or di-ionised water and some bicarbonate of soda.

If you haven't got a KH test kit just give me your address and I'll make some up for you and send it. it won't be exact but it'll be close enough to get you going.

Regards, Chris.


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## Cro (23 Jun 2009)

ceg4048 said:
			
		

> Are you using 4 dkh water?


No


			
				ceg4048 said:
			
		

> If so did the mixture turn yellow immediately?


yes


			
				ceg4048 said:
			
		

> Using RO water is worse than pointless. Please read the article I gave the link to.


I have, it states "The accepted practice is to fill the drop checker with distilled /deionized/RO water that has been adjusted to a known kH value" So my assumption (which I can see now was incorrect) was that all RO water was adjusted to the same known value. The RO water I have now is approx 20KH



			
				ceg4048 said:
			
		

> Have you washed the dropchecker with anything acidic, like vinegar for example?


No, just RO water.


			
				ceg4048 said:
			
		

> Test the pH of some other water like your tank water or tap water using the same indicator reagent. It could be duff.


I've used 2 different reagents and they both come out the same.


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## Cro (23 Jun 2009)

chris1004 said:
			
		

> Do what I do mate and don't tell her.


Was trying that, but a box full of chemicals (going EI soon) and another box containing 2 power heads dropped through the door today.   



			
				chris1004 said:
			
		

> Seriously though if your a bit stuck you can make your own 4kh solution if you have a kh test kit, RO or di-ionised water and some bicarbonate of soda.


I'll have to have a bash at that, thanks.


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## ceg4048 (23 Jun 2009)

Cro,
      It is absolutely impossible for RO water to have a KH of 20. Either you don't have RO water or your test kit is complete rubbish. A KH of 20 means that dissolved in that water is the equivalent of about 360 milligrams per liter of calcium carbonate. One of the main benefits of using an RO filter is that it totally removes carbonate ions from the water. So not only is this impossible it's an absurdity. Your test kit needs to be immediately tossed into the rubbish bin ASAP.

The dropchecker article states that the fluid must be RO water, but the water that comes out of the RO filter at exactly ZERO KH - and is then adjusted to a known kH value by adding carbonate back into that water. That means that a sufficient quantity of carbonate or bicarbonate compound, such as baking soda (sodium bicarbonate) is added to the water until the concentration of carbonate is 71 milligrams per liter, which equals a dKH of 4. One can add enough for a dKH of 5, or about 80 milligrams per liter. "Known" means that one knows exactly whether the value is; 4 or 5 or 6 or whatever. The color changes will vary based on that KH value that's why you have to "know" what the value is.

As Aaron and others have pointed out, if you will not use the 4 dkh water then you may as well not bother using the dropchecker at all because it will stay yellow until the cows come home. This is like having a non functional petrol gauge on your car and then deciding to use it to determine how much petrol is in the tank.

Cheers,


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## Dolly Sprint 16v (23 Jun 2009)

Cro said:
			
		

> My old JBL drop checker always showed the correct colour



As a quick fix until you can obtain you 4dkh solution - what ever solution you used in your JBL drop checker put it in your glass drop checker - problem solved.

Regards
Paul.


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## Cro (23 Jun 2009)

Flyfisherman said:
			
		

> Cro said:
> 
> 
> 
> ...


It was tank water, as per the instructions in the JBL box.


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## Cro (23 Jun 2009)

I've just done what you said Paul and hey presto, it's green.

However now I have no idea where I am lol. Will have to wait for 4dkh solution I suppose.


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## aaronnorth (24 Jun 2009)

tank water is just as bad too   

It contains other acidic substances in the water, basically what you are doing is using the same pronicples as a pH/ KH relationship chart, hence why they are innacurate


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## Cro (24 Jun 2009)

aaronnorth said:
			
		

> tank water is just as bad too


I know that now, but the instructions that come with the JBL drop checker tell you to use tank water.


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## Dolly Sprint 16v (24 Jun 2009)

Cro said:
			
		

> aaronnorth said:
> 
> 
> 
> ...



Red Sea DC - Red Sea recommend using tank water + their solution, last year i ran with a Dennerle DC with their solution in the tank and a Red Sea DC with their solution + tank water along side one another to compare colouration - very slight difference in colour.  

Paul.


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