# Drop Checker Instructions



## fluffiebuggie (Sep 25, 2007)

I bought a drop checker to get a better idea of what the CO2 levels are like in my tank on a regular basis, but it arrived today without any instructions in English.
It came with co2 test fluid, but I have no idea how much to add to the water in the chamber or how to best calculate (if calculation is needed)

Any help would be appreciated.


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## exterminator (Mar 26, 2005)

Here's the link to a topic where drop checkers were discussed in detail: http://www.aquaticplantcentral.com/forumapc/do-yourself-aquarium-projects/32100-diy-drop-checker-2.html

The instructions that come with drop checkers only confuse people.


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## Left C (Jun 14, 2005)

You only need about 2 to 3 drops of indicator fluid with you known dKH solution in your drop checker.

I used billionzz's instructions and made my own 4 dKH solution. Billionzz also sells the solution already made up. I believe that Blacksunshine sells 4 dKH solutions as well.
how to amke the solution: http://www.aquaticplantcentral.com/...lants-discussions/37077-how-kh-standards.html

solutions for sale by billionzz: http://www.aquaticplantcentral.com/forumapc/sale-trade/37080-kh-standards.html

Backsunshine: http://www.aquaticplantcentral.com/forumapc/sale-trade/38553-fs-co2-drop-checkers.html


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## exterminator (Mar 26, 2005)

Left C said:


> You only need about 2 to 3 drops of indicator fluid with you known dKH solution in your drop checker.


I don't think 2-3 drops is enough. It's really hard to see the color of the solution. I add 7-8 drops. The color is much more visible this way.


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## Mr. Fish (Oct 24, 2007)

Your only supose to add 2 drops.... with 4KH distilled water


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## hoppycalif (Apr 7, 2005)

As long as you aren't adding about as much indicator solution as you have 4 dKH water, it doesn't seem to make any difference how much you use. I have added way too much a few times to see how that worked, and the effect was that the water was too opaque to accurately judge the color. In the typical ADA style drop checker I add three drops of reagent. I suspect up to 5 drops or 6 drops wouldn't make it inaccurate. I'm pretty sure that reagent is slightly alkaline, so adding too much would have to skew the reading towards the blue side.


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## exterminator (Mar 26, 2005)

I'm using this drop checker:

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&rd=1&item=250173314617&ssPageName=STRK:MEWN:IT&ih=015#ebayphotohosting









When I was adding drops from the reagent that came with it, even 7-8 drops weren't making it opaque. It was perfectly dark blue. After it turns green, the liquid becomes very light. I tried a concentration with less drops and it was really hard to see the color. I used to put a white plastic spatula behind it, to be able to see it.

I think it works right, because my PH/KH calculations for CO2 match the drop checker color.

I haven't tried API PH test regent, as hoppycalif was suggesting, yet. This one might work with 3-4 drops.


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## hoppycalif (Apr 7, 2005)

I wasn't at all happy with the little bottle of reagent that came with my drop checker, which looks exactly like that one. My test samples in the pH kit test tube, using the reagent that came with the drop checker, were always muddy looking. From what I read on the internet making a good pH reagent with bromothymol blue, a dye, requires mixing in some sodium hydroxide (?) as I recall, plus some water. It is obviously a mix that can be varied quite a bit, either on purpose or by error. So, I felt I wanted to trust the API reagent and couldn't trust the one that came with the drop checker.

Incidentally, those instructions that came with that drop checker are wrong in recommending use of either tap water or distilled water. It has to be distilled or deionized water. They are also wrong to say to fill the bulb 2/3 full of water. It should be filled just to the middle - about half or less full. You need the maximum surface area of the water in the drop checker to get the fastest response time.


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## fluffiebuggie (Sep 25, 2007)

Thanks for the help guys.

I'm probably a little more confused about the one I bought as the little pictures on the box seem to suggest filling it to the brim with tank water.  

I'll have to have another read of everything before I decide to try it.

Incidentally, is there any other accurate method of assessing how much co2 is in the tank?


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## Mr. Fish (Oct 24, 2007)

Well I use Edwards method which is pretty effictive.

Do a test and find out what your KH is.
Say its *150* you multiply it by *0.056* which would be *10*
Then find out what your PH is, say its *7.2*

You would take both those numbers to Edwards chart and figure how much Co2
is actually in the tank

*Chart here:* http://ca.geocities.com/[email protected]/CO2.Table.6.to.8.gif

Now according to Edwards chart 10 KH and 7.2 PH would be 19 ppm which is efficient.

So just find out YOUR numbers and plug em into the chart... Thank Edward


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## hoppycalif (Apr 7, 2005)

Mr. Fish said:


> Well I use Edwards method which is pretty effictive.
> 
> Do a test and find out what your KH is.
> Say its *150* you multiply it by *0.056* which would be *10*
> ...


That method works very well when the only things in the tank water affecting pH are CO2 and carbonates, and if the only thing affecting alkalinity is carbonates. Unfortunately, those requirements are very rarely met in an aquarium. We get tannins affecting pH, we get phosphates affecting alkalinity, and whatever else is in the water as fertilizers or as added by the water company. Most municipal water companies add phosphates to keep the pH above 7 to avoid deterioration of copper piping. And any dead plant matter or peat will be adding tannins.


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## Mr. Fish (Oct 24, 2007)

Thats true... Best way to go around that is a PH Controller right ?
You really think they worth the $180 ?


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## hoppycalif (Apr 7, 2005)

A pH controller does not get around the problem I described.


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## FacePlanted (Aug 13, 2007)

Hence using the drop checker with a known KH.
You know exactly what's in it - bicarb, H2O, co2, reagent - nothing else to skew the readings.


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