My New Drop Checker

donkey

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Jun 21, 2005
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Hi all
a few days ago i got my new drop checker from a guy off Ebay .and i just want to make sure i have it working right .ok this is what i did .i could not get hold of any distilled water for love nor money . in the end i got some De-ionised water from a car shop .for £1.99 a Litre. i then found i could get a Litre bottle from wilkinsons for 54p . just my luck .Anyway i mixed some bicarbonate of soda in with the de-ionised water till i got a reading of 4 degrees KH water . i checked this with my KH test kit . i then added 3 drops from my PH kit till it went a dark blue color . heres some pics of how it looks going through its color change .do you guys think this looks ok .

the first pic is just after it was put in the tank . the next one is it starting to go from blue to green after about 2 hours . the last one is after 3 hours
 

VaughnH

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That looks just right to me. Congratulations! You now can be sure you have adequate CO2 in your tank.
 

donkey

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Jun 21, 2005
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Thanks guys ,its nice to know im doing something right :D .i have been reading on another forum that some people are baking the bicarbonate of soda and mixing it with 5 Litres of water .is this something i should be looking in to
 

Tom Barr

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I think the UK's Aquaessentials is carrying the pre mixed referenced KH solution for a few$.

Might be easier.

You figure 6mls every 2 weeks of KH ref solution abnd 500mls will go a long way, a little over 3 years and will be about 100-1000X more accurate. Note, even the baking soda method is still about 5-10x better than a KH test kit.

You can also double the amount, or triple it, when using the KH test kit BTW.

So if the test says to add 5mls and each drop = 1 KH unit(17.86ppm), then 10mls will yield each drop 1/2 KH unit (or 8.93ppm).

The accuracy of the Ref solution will be about 0.01-0.001ppm or so.

So then the only area of measure that's less accurate is the pH measurement.

And that's up to your eyeballs and color perception, or you can switch over to the
pH meters.

Regards,
Tom Barr
 

donkey

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Jun 21, 2005
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Thanks Tom .i just sent a email to Richard over at Aquaessentials and he tells me that they will be selling the pre mixed referenced KH solution soon .in about 10 days time . so i think i will wait for that . as this will work out cheaper than mixing my own .
 

donkey

Junior Poster
Jun 21, 2005
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England
Hi
I think i have a problem with my Drop checker . my lights and co2 are on for 10 hours a day and there off for 14 hours a day .but today i was looking at my drop checker just before the lights come on and it was still green and there had not been any co2 put in the tank for 14 hours .how can this be ? anyway i took the drop checker out of the tank and after about 2 hours it turned blue ( no co2 ) so this would mean that my tank is keeping 30ppm of co2 in it for 14 hours . how can that be right ?
 

Tom Barr

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Might want to change out the solution inside the drop checker, also, place it where some current flows past it.

Regards,
Tom Barr
 

donkey

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Jun 21, 2005
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Thanks Tom .well i can rule out one of them .i have it near a flow so it cant be that .so i will change out the solution and see how that works out
:)
 

Frolicsome_Flora

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Jan 12, 2007
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Ive had a similar problem in the last few days with drop checkers not returning to blues.. Ive done a few couple of days tests, and it turns out it was the regeant that came with my boyu glass checker. I put some from a different manufacturer (red sea) and its fine.

The boyu regeant was failing to decrease in green to blue after only 24 hours active. Odd. So Ive binned that bottle.. maybe it had been on the shelf along while? Do they have a shelflife?
 

Tom Barr

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The Red Sea brand should do well, cannot say about the others.

I use bromoblue which so what Red Sea uses, it's about 3$ for 5 year's worth.
Add 3 drops to 6mls of KH solution.

Note, with the accuracy of the KH ref drop checker, the volumes of the pH indicator and the volumes of the KH ref solution also come into play as well.

The higher accuracy those are, so will the readings.

No one has said too much about this.

Regards,
Tom Barr
 

Frolicsome_Flora

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I actually wondered about the amounts of agent used, if you dont put much water in it, like alot dont to speed up the reaction, then dump 5 drops of regeant in it, how does that effect accuracy? would be an interesting thing to test with a proper PH meter.

Does regeant absorb CO2 at the same rate as water?
 

VaughnH

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pH reagent is yellow out of the bottle, so it is a low ph substance. If you added one drop of distilled water to a cc of pH reagent it would obviously not give a good reading of the pH of the water. So, there has to be a point where you are adding too much reagent, and that would tend to make the drop checker stay green. My testing indicated that I could triple the recommended dose of reagent, 9 drops per test tube sample instead of 3 drops, and the color was still the same, just more intense. As we go to very small volumes of water in the drop checker there must be a point where we will be adding too much reagent. But, I don't know where that point is.

The cheap reagent that came with my ADA knock off drop checker isn't as good as what I get in an AP test kit. It is murky even in the 3 drops per test tube amount. That tells me there are good test kit brands and bad.
 

donkey

Junior Poster
Jun 21, 2005
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i have just change out the solution in my drop checker . i will let you know if it works any better after this
;)
 

kazooless

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Sep 24, 2006
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San Diego
That's a Good Point

VaughnH;14491 said:
pH reagent is yellow out of the bottle, so it is a low ph substance. If you added one drop of distilled water to a cc of pH reagent it would obviously not give a good reading of the pH of the water. So, there has to be a point where you are adding too much reagent, and that would tend to make the drop checker stay green. My testing indicated that I could triple the recommended dose of reagent, 9 drops per test tube sample instead of 3 drops, and the color was still the same, just more intense. As we go to very small volumes of water in the drop checker there must be a point where we will be adding too much reagent. But, I don't know where that point is.

The cheap reagent that came with my ADA knock off drop checker isn't as good as what I get in an AP test kit. It is murky even in the 3 drops per test tube amount. That tells me there are good test kit brands and bad.

Vaughn,

That's a good point. My Red Sea Indicator only uses 2 ml of KH solution. I think I only put in 3 drops, but maybe that's too much. I was suspecting that maybe it wasn't accurate, because it was staying green the whole time. So, I moved it to my non-planted tank (in case I need a medicine tank, I have it up and running) and it went to blue. Put it back in the planted tank and sure enough, it was green.

I'm pretty sure this means it is reliable. The solution I made tests to be about 4.4 or 4.6 KH.

What do you think?
 

VaughnH

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I think you have 25 to 45 ppm of CO2 in the tank. The surface movement isn't enough to outgas the tank during the night, so the drop checker stays green.