# Did I waste my money on a drop checker?



## Nlewis (Dec 1, 2015)

I think my drop checker is useless. This is my first time having one and the color never changes. I believe it is due to the fact my ph is already low, around 6.5. Am I doing something wrong?


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## benealing (Jan 9, 2015)

Are you using tank water or 4 dKh water? You have to use the later in order for it to be accurate. It also lags by an hour or so. You may also not be injecting enough CO2 for the color change.

Ben


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## Nlewis (Dec 1, 2015)

benealing said:


> Are you using tank water or 4 dKh water? You have to use the later in order for it to be accurate. It also lags by an hour or so. You may also not be injecting enough CO2 for the color change.
> 
> Ben


Yes I'm using the 4dkh fluid. Co2 has been off for 12 hours now and the drop check is yellow. Should I try and change the fluid?


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## benealing (Jan 9, 2015)

It should not be a problem with the fluid if you are still seeing the color. Have you tried checking the pH of your water when the CO2 is off and when it is on. If you are getting CO2 into the tank, you will see a drop in the pH. If you are getting a drop by measuring the pH and the drop checker is not changing, then the drop checker is not effectively working and you can look into reasons for that. 

The first thing I would do is check for the pH drop before trouble shooting the drop checker.

Ben


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## Nlewis (Dec 1, 2015)

benealing said:


> It should not be a problem with the fluid if you are still seeing the color. Have you tried checking the pH of your water when the CO2 is off and when it is on. If you are getting CO2 into the tank, you will see a drop in the pH. If you are getting a drop by measuring the pH and the drop checker is not changing, then the drop checker is not effectively working and you can look into reasons for that.
> 
> The first thing I would do is check for the pH drop before trouble shooting the drop checker.
> 
> Ben


Ok, I'll check ph now and again later after the co2 has turned on and report back.


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## benealing (Jan 9, 2015)

Also, it is very helpful to start the CO2 about an hour prior to the lights coming on (and turn off an hour before the lights) so you get effective levels for the plants once the photoperiod starts.


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## Greggz (May 19, 2008)

Nlewis said:


> Yes I'm using the 4dkh fluid. Co2 has been off for 12 hours now and the drop check is yellow. Should I try and change the fluid?


If the drop checker is yellow, that would indicate a very high level of co2.

I would change the fluid. It should be blue after you mix it. If it turns from blue to yellow, I would say it is working.

Like others said, might be good to measure ph on some degassed tank water vs. co2 injected water. The ph drop should help determine about where you are.


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## Nlewis (Dec 1, 2015)

Greggz said:


> If the drop checker is yellow, that would indicate a very high level of co2.
> 
> I would change the fluid. It should be blue after you mix it. If it turns from blue to yellow, I would say it is working.
> 
> Like others said, might be good to measure ph on some degassed tank water vs. co2 injected water. The ph drop should help determine about where you are.


I jad a second drop checker due to Amazon sending one without fluid. I added the second one 5 hours ago. It is blue and has not changed color. Tap water ph is 6.0, when I tested earlier before the co2 came on it was 7.6(not sure why it's rising). Tested just now and the ph is around 6.6.


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## dukydaf (Dec 27, 2004)

What is your KH ?

So the color of the drop checker is yellow when CO2 is off and blue when CO2 is on ? Are you sure it is not the other way around ?

To get the accurate, degassed pH of the aquarium you will need to get a sample of the aquarium water and leave it for 24h.

Keep in mind, the first time you put the drop checker in the water after it was exposed to air it will take longer for the color to change. The rest of the time it would have a lag of 1-2hours.

The pH of the tap water might be lower because it has higher CO2 than your aqurium or something in the aquarium increases the pH, either way I would not worry about a specific pH. It is the combination of the pH-KH that gives a hint of the level of CO2. The drop checker adds a second level of control in case your KH/pH measurement was otherwise influenced.


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## Nlewis (Dec 1, 2015)

dukydaf said:


> What is your KH ?
> 
> So the color of the drop checker is yellow when CO2 is off and blue when CO2 is on ? Are you sure it is not the other way around ?
> 
> ...


No it's yellow at all times and the KH is 4.


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## dukydaf (Dec 27, 2004)

Nlewis said:


> I added the second one 5 hours ago. It is blue and has not changed color. Tap water ph is 6.0, when I tested earlier before the co2 came on it was 7.6(not sure why it's rising). Tested just now and the ph is around 6.6.





Nlewis said:


> No it's yellow at all times and the KH is 4.


Previously you said it is blue and did not change color.

Just to be clear, the KH of the aquarium water is 4, yes ?

If you have a pH of 6.6 and KH of 4 you would be around 30ppm and the dropchecker should be green. Meaning that either you are underestimating the KH of the aquarium (unlikely) or the overestimating the pH (more likely) or something is wrong with the liquid/drop checker. What method are you using for measuring the pH.

If the liquid is yellow it means to much CO2. Try this:

* take it out of the water, expose the liquid to air. What color does it turn and how fast ?*


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## Nlewis (Dec 1, 2015)

dukydaf said:


> Previously you said it is blue and did not change color.
> 
> Just to be clear, the KH of the aquarium water is 4, yes ?
> 
> ...


Let be back track a bit. The original drop checker installed in the tank is yellow and never changes color. I checked it this morning and the co2 had been off for 10 hours and it was still yellow. I tested the water before the co2 came on earlier and the ph was 7.6 and I checked again about an hour ago and it was 6.6. The co2 had been running for about 4 hours during the second test. 

I had a second drop checker here, so I installed one earlier before the co2 came on. That drop checker has remained remained a blue/green color and has been in there with co2 running for 6 hours. 

Yes, the KH is 4 and was tested yesterday. 

I have pulled the original drop checker(yellow one) and its been out for 5 minutes now with no change in color.

Is it possible I mixed the solution wrong? I filled the 4DKH fluid to the lined indicated on the checker and put in 5 drops of the co2 solution.


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## dukydaf (Dec 27, 2004)

It might need more than 5 minutes, more like 30min-1h. drop checkers react very slowly.

It might be that the drop checker was contaminated with residues. So wash them in RODI water and dry it, then remake the solution. When in air it should be blue, put it in a high CO2 water and it should turn green and then yellow. If this does not happen the solution was wrong. I mostly change the solution in the drop checker because it gets contaminated with aquarium water...

Based on the ph-KH chart you would want to add CO2 until you have a pH of 6.5 at KH 4. The drop checker would then turn a shade of green. Until you figure out what is happening with the solution of the drop checker you may want to base your CO2 values on the ph-KH values.

CO2/pH/KH table - Aquarium Plants - Barr Report


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## Greggz (May 19, 2008)

Nlewis said:


> I jad a second drop checker due to Amazon sending one without fluid. I added the second one 5 hours ago. It is blue and has not changed color. Tap water ph is 6.0, when I tested earlier before the co2 came on it was 7.6(not sure why it's rising). Tested just now and the ph is around 6.6.


Your tap water more than likely contains lots of co2. I would take some tap water, and leave it out for at least 24 hours, then check ph. It rises because eventually becomes degassed.

For instance, my tap water comes out at 6.85ph, and degassed is at 8.25ph.

Also are you testing with test kit or meter? A calibrated meter is more trustworthy than a test kit. I've done them side by side, and the test kit is really an educated guess, and can really vary depending on how you interpret the colors.


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## rick dale (Feb 26, 2014)

You are right about one thing. Drop checkers are useless. Invest a hundred bucks in a good pH monitor . I have a high tech heavy planted tank. I bought the best drop checker money could by. Needless to say , its in the trash now. They're always an hour or more behind. And if it's not placed right in your aquarium it will never read correct. It will keep you wandering and adjusting. Get a good pH monitor with good tank circulation is the answer.


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## benealing (Jan 9, 2015)

For me, I use the drop checker as a quick and easy monitor. I have used it for so long that I know what/when things change color. If I see a difference one day, I can trouble shoot it.

I personally would only use a pH meter if I were trying to run my CO2 to the max OR if I used is as a safety to turn off the CO2 in a end of tank dump like situation.

From a minimalist point of view, any CO2 monitoring equipment is really not needed. I can watch my fish to determine if CO2 is too high and watch the plants to check for too little CO2. The equipment is only useful if I choose to act on what I am seeing (which I can do with visual inspection of the tank anyway).

If I had very expensive fish, I would have a pH controller as a fail safe to prevent death if I am not around to observe for CO2 toxicity.

This hobby can be as complicated as I want it to be.


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## Aechele (Mar 11, 2016)

I was kind of feeling like my drop Checker was useless too. Bought the Fluval checker. No mixture to it, just at the solution that comes with it basically has stayed blue no matter what I've done


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## benealing (Jan 9, 2015)

I wouldn't describe them as useless. You just have to understand how they work and understand their limitations.
Ben


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## jrill (Nov 20, 2013)

I think useless is close to accurate. Try and count how many posts comment on issues that clearly are co2 related but state how that can't be because their drop checker has the right color. But, others will disagree.

Sent from my XT1585 using Tapatalk


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## benealing (Jan 9, 2015)

Definitely different strokes for different folks.

Ben


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## Hoppy (Dec 24, 2005)

Nlewis said:


> I jad a second drop checker due to Amazon sending one without fluid. I added the second one 5 hours ago. It is blue and has not changed color. *Tap water ph is 6.0*, when I tested earlier before the co2 came on it was 7.6(not sure why it's rising). Tested just now and the ph is around 6.6.


Tap water should never be that low in pH. At that pH the water will leach copper from the copper piping, and lead from the solder used to assemble the piping. If it truly is that low, you have a very major problem, far exceeding aquarium problems.

A drop checker works to measure the CO2 in the water by having 4 dKH water in the bulb of the drop checker, with that water being distilled or RO/DI water with nothing in it but bicarbonate of soda to achieve the 4 dKH. Then, that water should have 2-3 drops of bromothymol blue pH reagent (API pH reagent, for example) added to it. It works because the ppm of CO2 in the drop checker will be the same as that in the aquarium water, if you wait long enough, and the drop checker is designed correctly. It will not work if those conditions are not true for your setup. You cannot ever use the solutions that are included with a commercial drop checker, especially one made in China. Buy 4 dKH water from an experienced planted tank hobbyist or make your own 4 dKH water from distilled water and baking soda. Use your own pH reagent assuming it is one that is yellow at around 5.5 pH and blue at around 7.5 pH.

Contrary to what so many people say here, drop checkers do work. You may find their very slow response isn't acceptable to you, but that doesn't mean they don't work. And, they don't give an accurate reading, just a good enough approximation to let you know your CO2 bubble rate is in the right ballpark. If you want an accurate reading on how much CO2 is in the water you have to spend at least hundreds of dollars. But, we have no reason to want an accurate reading.


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## Slawman (Apr 12, 2015)

I have never found drop checkers useful, but I use a PH monitor for my CO2 system. 

I would use one if I did not have an electronic PH monitor so I didn't accidentally kill my fish.


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## Nlewis (Dec 1, 2015)

Well it did not change again today and I even bumped up the co2. I think something may be wrong with one of the fluids because when I put them in the checker they turn green not blue.


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## neilshieh (Sep 6, 2010)

Hoppy said:


> Tap water should never be that low in pH. At that pH the water will leach copper from the copper piping, and lead from the solder used to assemble the piping. If it truly is that low, you have a very major problem, far exceeding aquarium problems.
> 
> A drop checker works to measure the CO2 in the water by having 4 dKH water in the bulb of the drop checker, with that water being distilled or RO/DI water with nothing in it but bicarbonate of soda to achieve the 4 dKH. Then, that water should have 2-3 drops of bromothymol blue pH reagent (API pH reagent, for example) added to it. It works because the ppm of CO2 in the drop checker will be the same as that in the aquarium water, if you wait long enough, and the drop checker is designed correctly. It will not work if those conditions are not true for your setup. You cannot ever use the solutions that are included with a commercial drop checker, especially one made in China. Buy 4 dKH water from an experienced planted tank hobbyist or make your own 4 dKH water from distilled water and baking soda. Use your own pH reagent assuming it is one that is yellow at around 5.5 pH and blue at around 7.5 pH.
> 
> Contrary to what so many people say here, drop checkers do work. You may find their very slow response isn't acceptable to you, but that doesn't mean they don't work. And, they don't give an accurate reading, just a good enough approximation to let you know your CO2 bubble rate is in the right ballpark. If you want an accurate reading on how much CO2 is in the water you have to spend at least hundreds of dollars. But, we have no reason to want an accurate reading.


Having read through this thread, I'm having a hard time figuring out why people are still butting heads and the problem hasn't been solved with one page of comments yet. 
Hoppy and a few others have laid it out pretty simply here: The science behind how drop checkers+bromothymol blue+4dkh water and co2 levels work has been established and it works. If your drop checker doesn't change color or has the wrong color it can ONLY be one of three things. 
1) bad circulation/placement of the drop checker. 
2) you're not using 4dkh solution which should just be pure water adjusted to 4dkh with only carbonates/bicarbonates. 
3) you're not using bromothymol blue

If it's #1, move your drop checker or increase circulation. If it's #2 or #3 figure out which reagent is the problem and replace it (ph indicators are generally bromothymol blue-esp if you use the API one. it's most likely 4dkh solution that's the culprit, most companies do not provide actual 4dkh solution or tell you to use tank water. this is *incorrect* you must use legitimate 4dkh solution which you can buy from sellers in for sale/trade section of TPT or you can make it yourself with RO/DI water and baking soda) 

Secondly, understand the limitations of the drop checker. It's not going to give you a precise ppm count, only general ranges of where your co2 levels are. Blue=not enough co2, Green=good amount of co2, Yellow=Too much co2/bordering deadly. For most people all they need to know is if they have enough co2 or not. Knowing your exact ppm or co2 induced pH drop won't make your plants grow any better. Probably the only reason you'd need to buy a ph monitor is as a failsafe for expensive livestock. You're paying less than 10 dollars for a glass ornament and some colored liquids, there's no use in comparing how "useful" or "accurate" it is to a ph monitor. The drop checker is for a quick visual reference to general co2 levels and there's a 1-2 hour lag time for color changes associated with co2 level change. Dialing in your tanks various parameters is a gradual process, not something you just set values to in an hour and expect to run smoothly forever.

Whether you do or do not think a drop checker is useful is your opinion which you're fully entitled to, but the science behind how drop checkers work has been established and is fact. so to each and their own...


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## kilauea91 (Sep 19, 2013)

Let me take a guess of your problem from the clue given in your picture: 

you overfilled the solution in the drop checker and had the vent hole blocked. Overfilling may also have contaminated your solution with your tank water. You need to keep the vent hole clear of the liquid allowing the degassed co2 entering the chamber to react with the solution .Normally, it should look dark blue (the color of bromo blue) instead of staying green - an indication of contaminated solution in your photo. 

A tip for shortening the color changing reaction time is to maximize the area of the solution exposed to air inside the chamber, in which case, the less the better. 


From the 


Nlewis said:


> Let be back track a bit. The original drop checker installed in the tank is yellow and never changes color. I checked it this morning and the co2 had been off for 10 hours and it was still yellow. I tested the water before the co2 came on earlier and the ph was 7.6 and I checked again about an hour ago and it was 6.6. The co2 had been running for about 4 hours during the second test.
> 
> I had a second drop checker here, so I installed one earlier before the co2 came on. That drop checker has remained remained a blue/green color and has been in there with co2 running for 6 hours.
> 
> ...


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## Nlewis (Dec 1, 2015)

kilauea91 said:


> Let me take a guess of your problem from the clue given in your picture:
> 
> you overfilled the solution in the drop checker and had the vent hole blocked. Overfilling may also have contaminated your solution with your tank water. You need to keep the vent hole clear of the liquid allowing the degassed co2 entering the chamber to react with the solution .Normally, it should look dark blue (the color of bromo blue) instead of staying green - an indication of contaminated solution in your photo.
> 
> ...


i think I may have found the solution. I believe the solution that came with the drop checker is bad. When added to the 4dkh fluid the mixture would turn green. I just changed the fluid and added 3 drops of the ph test fluid from my api test kit. To my surprise the mixture turned blue. I guess I'll see what happens in about 12 hours.


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## Nlewis (Dec 1, 2015)

Alright I woke up this morning to find the drop checker is green and the co2 has been off for 12 hours. I just tested the water with the api kit and the ph is around 7.6(blue). What am I missing?


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## dukydaf (Dec 27, 2004)

Good to see that you got a good lead.Depending on the shade of green, everything seems ok. Did color become more towards yellow after several hours of CO2 on, maybe when pH is below 6.6?

The reason the drop checker stays greenish is that you have some CO2 'leftovers' even after 12h (now you can see why we asked to measure the pH of a sample of aquarium water after 24h). The drop checker mainly turns back to blue when air is allowed in the chamber.


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## Nlewis (Dec 1, 2015)

dukydaf said:


> Good to see that you got a good lead.Depending on the shade of green, everything seems ok. Did color become more towards yellow after several hours of CO2 on, maybe when pH is below 6.6?
> 
> The reason the drop checker stays greenish is that you have some CO2 'leftovers' even after 12h (now you can see why we asked to measure the pH of a sample of aquarium water after 24h). The drop checker mainly turns back to blue when air is allowed in the chamber.


Yeah it turns lime green. I need to check and see what color it is when I leave for work in the morning to make sure it's changing. I did find out though that the well water does have a lot of co2 in it. Someone, maybe you stated earlier in the thread that a may have high co2 content right out of the tap. I tested and got 6 from the tap and 7.6 from some water I left out for a few hours.


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