# PH controller vs. Drop Checker



## nivekid (May 2, 2006)

Here's my question. I already have a pH controller in my aquarium. It seems to work ok, emphasis on ok. Is a drop checker really much more accurate? Is it worth the extra cost and clutter? A simple question, but we'll see if there's a simple answer. Is there ever a simple answer.


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## Squawkbert (Jan 3, 2007)

I'd use both if I were in your shoes.

A yellow drop checker is a sure sign that your pH controller needs some probe cleaning/calibration - whatever, or that you have a sticky solenoid or other problem.

Think of it as "belt and suspenders".


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## nivekid (May 2, 2006)

A belt and suspenders huh. That sounds pretty good to me. I actually might wait a bit because I just got done cleaning and calibrating my controller. I couldn't believe it. It was .5 off! It read 7.5 in the 7.0 calibration fluid. I probably haven't had enough CO2 for quite a while. That could also explain why I've had algae for quite a while. Right now a belt and suspenders does sound pretty nice.


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## jmhart (Nov 13, 2007)

I use both....redundancy redundancy redundancy.

Originally, I used only the drop checker, but when I acquired the pH contoller, the drop checker was useful in determining what pH to set my controller at.At it's heart, a pH controller uses the same concepts behind the pH vs KH table, which we've all read can be slightly inaccurate. That's why it was nice to have had my drop checker setup and working at the co2 level I wanted, pop in the pH probe, let it adjust, and then tell the pH controller to keep it at that pH.

Now, with both working, I can get an idea if it's time to recalibrate either of them.


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## nivekid (May 2, 2006)

I never thought of that. Well, it looks like that will be my next purchase. Any recommendations on brand or style?


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## jmhart (Nov 13, 2007)

$13 shipped from Asia off ebay.


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## ray-the-pilot (May 14, 2008)

I use a drop checker with my CO2 controller. You can think of your controller as a thermostat and the checker as a thermometer. They verify each other. As long as the color in the checker hasn’t changed and the pH reading on your controller is the same you are under good control. I haven’t recalibrated my controller in months.

It doesn’t matter what brand you buy. I have the cheap Red Sea Checker in my aquarium.


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## Tex Gal (Nov 1, 2007)

My favorite DC is the red sea one. It's nothing fancy, but it's easy to clean and change.


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## Left C (Jun 14, 2005)

Plus the Red Sea model has a white center so that you can see the color better.


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## gibmaker (Jan 3, 2007)

Just curious, if the drop checker is always accurate then why use a ph controller that needs recalibrating? It's just something else that needs maintenance IMO. I can see using one if you are trying to get to a specific ph and keep it there. It can save you co2, but how many times do you need to fill your tank to make the ph controller worth it? I don't use one and never had so I guess my opinions are all just hear say. If it aint broke don't fix it.


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## ray-the-pilot (May 14, 2008)

If you don’t have a CO2 controller there is no way to determine what the CO2 level is in your tank. Without a controller, the level will depend on the time of day, the location in your tank, the number quantity and health of plants and fish etc. These can result in a 100 fold variation in the level of CO2. 

A drop checker only gives the approximate average CO2 level at one location and it does not control the level of CO2. It is really only a ballpark estimate under these conditions.

With a CO2 controller, the CO2 in your tank is always the same everywhere. There are no hot spots, dead spots, changes with plant and fish activity…no changes period. Now the average CO2 level at one location is the exact CO2 level for the whole tank.

BTW I haven’t calibrated my controller in 3 months and I know it is still OK. 
Whenever I bump into my drop checker and knock it off the glass I clean and refill it. I clean and refill my drop checker more often than I calibrate my controller.


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## pjbc (Jun 28, 2005)

ray-the-pilot said:


> With a CO2 controller, the CO2 in your tank is always the same everywhere. There are no hot spots, dead spots, changes with plant and fish activity&#8230;no changes period. Now the average CO2 level at one location is the exact CO2 level for the whole tank.


Sorry but I don't agree with this sentence!

Yes, a Co2 controller give you a more stable PH/Co2,
but the circulation of water is essential for a good co2 distribution, 
you can have dead/hot spots with or without the controller!

In my opinion, the controller, if correctly calibrated/used, will give you less fluctuation of PH/Co2
and the co2 bottle will last longer, but it's not essential!

The drop checker is a visual aid..... it will give you a visual alert if the controller "go mad"!


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## helgymatt (Sep 12, 2007)

^What he said....but I better not get into this one!

You have to buy a $1000 meter to know if you have the SAME CO2 concentration ALL over your tank.


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## ray-the-pilot (May 14, 2008)

<<With a CO2 controller, the CO2 in your tank is always the same everywhere. There are no hot spots, dead spots, changes with plant and fish activity&#8230;no changes period. Now the average CO2 level at one location is the exact CO2 level for the whole tank>>

This is not an opinion this is a scientific fact!

If you go here and open CO2 paper part 2 and go to table 3:
http://www.aquaticplantcentral.com/forumapc/equipment/59274-how-set-up-your-co2-controller.html

You will see that there is only a statistically insignificant variation in CO2 levels in a typical CO2 controlled tank.

I think are referring to a (CO2 in = CO2 out) system. In these uncontrolled systems the range in CO2 levels can be almost 100 fold. 
See Tom Barr:
http://www.barrreport.com/co2-aquat...eal-time-data-localized-co2-ppm-readings.html


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## ray-the-pilot (May 14, 2008)

*Dragging people out of the dark ages!*



helgymatt said:


> ^What he said....but I better not get into this one!
> 
> You have to buy a $1000 meter to know if you have the SAME CO2 concentration ALL over your tank.


You can buy a good CO2 controller for $110.00

http://www.aquariumplants.com/Automated_pH_Co2_Controller_MILWAUKEE_SMS122_p/pr209.htm

And a pH meter for $20.00

http://www.aquariumplants.com/pH_METER_Hand_Held_Milwaukee_pH600_p/pr1408.htm


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## helgymatt (Sep 12, 2007)

Well I can't resist...

Ray, In your thread you say your papaper is published. Where? 

You need to explain the CO2=CO2 out theory. And then explain why your tank has the same CO2 everywhere and Tom Barr's does not. Are you saying that because Tom is injecting CO2 at a contant rate during the day, the difference of CO2 concentrations he finds in his tank are only because of time? Do you mean that throughout the day the CO2 concentration will increase and then the CO2 does not get mixed evenly in the tank causing differences in CO2 concentrations? Surely the pump in Toms tank is mixing water throughout the tank and surely some areas of the tank do not get as mixed as well as others. 
Please explain why the CO2 controller would be any different than a needle valve injecting the same rate of CO2 24/7 (forget photoperiods and plants for now) 

You didn't explain if you have any plants in your tank. It would be nice to know if your tank is a box of water or a planted aquarium with places which may not have as much flow as others.

EDIT: I found how you mixed the water in your tank to get to equilibrium - you stirred it. Seems like a very logical way to equilbrilate the water! I know my tank doesn't stir itself to mix up the CO2 enriched water. I do have a pump for circulation, but I know that back corner and other areas of my tank have hardly NO flow. How would the CO2 measure in those area of the tank?

Also, for the record means and standard errors are not "scientific fact". Maybe you can do some more powerful statistical analysis and then have a stronger case. 

And BTW, I am not saying controllers are no good. I'm actually considering buying one. I just don't understand your logic.


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## Engold (Nov 4, 2006)

A drop checker is really valid if the known kh is equal to the aquarium's kh value. Plus the pH probe must be routinely cleaned and recal on a regualr basis, at least monthly recal.. but ultimately.... how does your tank look and are the fish gasping for air on the surface. If everything is lush and flourishing... leave it alone... you must be doing something right

Later!


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## ray-the-pilot (May 14, 2008)

helgymatt said:


> Well I can't resist...
> 
> Ray, In your thread you say your papaper is published. Where?
> 
> ...


Your question about publication is amusing! The fact that the paper is in the public domain and you can reference it, says that it is published. If you are asking whether I was paid for the rights to the paper; not yet so far.

If you look at table 3 you can see that the CO2 level stay constant over time and location to within a statistically insignificant +/- 2ppm. This is datum. Data are scientific facts!

The tank was NOT stirrer during the collection of the data for the distribution study. Only the normal tank circulation was used to mix the water.

The tank was only stirred to prepare the standard curve. This was necessary because a lot of CO2 was added each time and I didn't want it to outgas waiting for the tank to equilibrate.

If you go into my profile you can find the details of the tank as well as a picture.


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## helgymatt (Sep 12, 2007)

standard deviation and standard errors are not scientific facts! Any scientist knows this. Do a real statistical analysis. 

You didn't answer any of the other questions. I want you to explain to me in detail why Toms tank has different levels of CO2 all over his tank when he uses a needle valve to inject the same rate of CO2 into the tank all day.


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## ray-the-pilot (May 14, 2008)

helgymatt said:


> standard deviation and standard errors are not scientific facts! Any scientist knows this. Do a real statistical analysis.
> 
> You didn't answer any of the other questions. I want you to explain to me in detail why Toms tank has different levels of CO2 all over his tank when he uses a needle valve to inject the same rate of CO2 into the tank all day.


I already answered this question before. I suggest that you go over the post "Why live with a wood burning stove."

If you have any real desire to understand this please do it in a PM. This is way off topic for this thread.


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## helgymatt (Sep 12, 2007)

I've seen plenty of the wood burning stove. And no this is not off topic. The thread is about the +/- of drop checkers vs. ph controllers and what each can and CAN'T do.

I think everyone here would like a "real" explanation so do us all a favor and try to answer that question.


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## ray-the-pilot (May 14, 2008)

Have a nice day!


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## pjbc (Jun 28, 2005)

*ray-the-pilot: *
To keep things On-Topic, I moved my message to the other thread.


But I kept here my opinion: :tea:
-With controller the PH will not fluctuate much, maybe 0,2PH(?)
-Without controller you have bigger PH fluctuation, maybe 1PH,
but you will have the same death/hot spots than you had with controller.

_
(if moderators wish to delete this post, no problem!)_


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## ray-the-pilot (May 14, 2008)

I think I already did all that. I'm not sure why you cannot open the word files. It is probably something to do with your virus protection. 
I wanted to post the documents as PDF but the file size limitation made it impossible. 
If you want PDF copies PM me and I'll send them to you.


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## helgymatt (Sep 12, 2007)

ray-the-pilot said:


> Have a nice day!


It's a beautiful one here


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## inkslinger (Jan 1, 2005)

You need a good water circulation to start , I had always use a PH Controller in my 110g tank it keeps my PH at 6.5
I have a Mag 5 in a close loop system with a co2 reactor,uv light, and heater, My filter is a Eheim Pro 2 2028. I decided to buy a DC I install it in my tank and for the whole month it did not change color Blue?? I even went by BPS without the controller by the end of the day my PH was at 5.9 and that did not change the color it was still Blue??
Now I run my controller just to read the PH an run my CO2 {BPS} only when the lights come on. The DC is still in my tank for looks.


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## Supercoley1 (May 28, 2007)

This is an old one. lol

I haven't read your papers as I don't have time for that nor need to. All I will say that Ph Controller vs drop checker. Which is more accurate? Neither are more accurate than each other but the drop checker is more likely to be accurate r.e. CO2 because ituses a controlled solution (4dKH) whereas the Ph probe is in the tank water.

To try and assimilate CO2 to a certain Ph drop in the tank is useless. This drop can be from many variables of which CO2 is only one. There are many acids at work. Secondly the KH of your tank water changing can affect how much the drop will be.

Therefore as we know the solution in the drop checker is a certain KH then we know what the drop will be. In the tank water if there is a slight change in KH then the process is flawed immediatley.

To suggest that a setup with a Ph controller will have equal CO2 all the way round the tank whereas a tank with a drop checker and permanent injection will not is ridiculous. They will be the same.

The Ph controller will turn on/off relevant to the PH drop in the probe's area. Just as a drop checker will only give you the reading of the DCs area. You could add more probes around the tank and let the average control the CO2 but by the same argument you can use several drop checkers to see your levels.

The CO2 concentration in the water is dependent on the efficiency of the diffusion method and the circulation around the tank wether using a Ph controller or not.

The problem with using a Ph controller is that we want stable CO2 but this does not mean exactly the same all around a tank. This would be impossible without having a Tornado style circulation which would not let you have any plants or fish. We are aiming at an average and like Tom says in his article the further from the diffusor you are the lower the ppm is. Nearer to the diffusor is at toxic levels but the fish will not stay in this area. They will go in and out if they feel uncomfortable with it.

A Ph controller will turn on and off with the assumption that a certain drop is the relevant level of CO2 and therefore the further areas may fluctuate to the point that the plants in this area are constantly having to adapt to different levels and therefore not growing properly. non limiting the CO2 so that there is enough plus a bit more in the further areas means that they will grow really well.

I would say that the Ph controller used in conjunction with CO2 is nothing more than a glorified (and expensive) version of the Ph /KH chart which we all know (or at least should by now) is flawed!!!

Use it to monitor Ph levels, Use it as a safety mechanism so that it will cut off CO2 in the event od something else causing a Ph crash (but set it lower than your assumed Ph drop for CO2) but don't use it to control CO2 on or off!!!

I don't see this equipment being used in many of the succesful scapes around. I only see it being promoted by the same companies that promote substrate heating cables, and fertilisers with no N or P in them (using the no N or P as a selling tool.)

My suggestion would be save your S110. Get a coule of cheap thermometers for $2 each so you can check them against each other and get 3 or 4 cheap drop checkers $5 each. Now you've saved money there and can now afford the extra CO2. It will also save you the frustration of trying to work out why algae is growing your tank 

It's not rocket science. The Ph in the tank is not solely controlled by CO2 injection and therefore the tank water cannot be used to take a Ph drop reading for use with CO2. Therefore the Ph controller although being a clever piece of kit renders itself worthless in conjunction with controlling CO2!!!!

Do I have drop checkers? Yes but more for visual signs than anything else. When I setup the CO2 level I push it until I can see the fish going to the surface and then back it off a little. Then I leave it until the bottle has run out. The DCs (and me watching the plants/fish) will tell me if anything untoward is happening!!

AC


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## ashappard (Jun 3, 2006)

Supercoley1 said:


> This is an old one. lol


you can say that again.



Supercoley1 said:


> I haven't read your papers as I don't have time for that nor need to.


you aren't missing anything Supercoley1. I read it and winced at the flawed conclusion. No, I'm not a chemist / science guy but I can see through all the puffery. A flood of numbers does not equal a valid conclusion. The paper's experiments lack control and comparison. I'm used to seeing _*comparisons*_ of dry weights of plant mass after a growth cycle / O2 charts showing how one tank differs from another during growth cycles.. etc and so forth. The 'paper' reaches too far without collecting valid experimental data and makes a predetermined conclusion. That is not good science and it is misleading.



Supercoley1 said:


> The problem with using a Ph controller is that we want stable CO2 but this does not mean exactly the same all around a tank.


absolutely. better to save money on the bells and whistles - and work to manage good flow / efficient diffusion / and stable delivery of gas. That is what really matters.


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## ray-the-pilot (May 14, 2008)

Supercoley1 said:


> This is an old one. lol
> 
> I haven't read your papers as I don't have time for that nor need to. All I will say that Ph Controller vs drop checker. Which is more accurate? Neither are more accurate than each other but the drop checker is more likely to be accurate r.e. CO2 because ituses a controlled solution (4dKH) whereas the Ph probe is in the tank water.
> 
> ...


First off let me apologize if I sound critical. I'm not trying to put you down.

Almost everything in your post is your opinion. While I value your opinion and you are certainly entitled to it I have to point out that you do not own a CO2 controller so your opinion is not based on fact, only hearsay.

I do own a controller. I have collected data over time and made conclusions based on direct observations. I think that if you can afford one and have a tank big enough to support it they are extremely helpful in maintaining controlled levels of CO2.

One other point, now I know how Galileo felt when he told people that the Sun didn't revolve around the earth! (This is supposed to be a joke so don't take it seriously).


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## Engold (Nov 4, 2006)

> First off let me apologize if I sound critical. I'm not trying to put you down.


 taken from Ray The pilot

I don't think you are being tooo critical, after all, this is a free forum for all to share thoughts/opinion and most of all experience. I love this debate about CO2 chkers vs pH meters. I personally use pH and perfer it, but I have used a Drop Checker as well.

Ultimately, How good does your tank look with whatever set up inplace to control proper CO2 concentration. Right now.... my tank is pearling O2 like AAA tracers rounds in Baghdad during a night raid...... and my plants are flourishing..... enough about my tank.

If your tank is Lush and green.... awesome

Later!


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## nivekid (May 2, 2006)

Well, I didn't expect such a debate from my question. Just so you all know I purchased a drop checker and installed it last week. It is working great. After installing it in my aquarium I could see that I didn't have enough CO2 so I turned my Ph controller down in small increments until the drop checker was showing a nice green color. So, in the showdown between Ph controller and drop checker I say BOTH win, drop checker shows me when I have just enough CO2 and the Ph controller holds it steady at that point.


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## Supercoley1 (May 28, 2007)

Let me just say the following:

Can your system control CO2 - Yes because it can shut it off or turn it on automatically dependent on the Ph of the aquarium.

Can it control the level to a desire ppm - Only in certain cases:

-There are no other variables within the tank affecting the Ph of the aquarium

-The 'variables' stay constant  so that the user knows how much these variables are changing the Ph by at which point you then know the Ph drop for the KH @ a certain ppm, then add the variables (that aren't changing ) and there is your new point drop

-You get a drop checker style fitting that you can contain a controlled solution of a known refence Kh and then seal the probe within this solution.

You cannot use the Ph/KH charts to make your CO2 assumption. This has been known for sometime and proved inacurate by many sources within the hobby.

To say Tom Barr is backward is ridiculous. Whilst you are a chemist and probably using hobby test kits for your testing methods, Tom is a scientist using a laboratory and laboratory grade equipment!!!

I am with everyone else on here. Go onto the barrreport and post your statements. Prove that you are right not defend your theory without debating it. You dismiss everything that a lot of people are saying comparing them in a Simon Cowell way to non aquarium items.

You must prove what you say is fact not wait for it to be proved wrong. this is like the marketing of many products that companies sell for the aquarium where they release things based on non aquarium science or old beliefs and defy the facts when someone tests it!!!

Summary : Can your system control the CO2? - yes of course it can BUT you do not know day to day what the level actually is due to the high number of variables that are involved using your method of calculation. Will it be constant all the way round the tank? - No it will be the same as with a drop checker. Circulation is the factor in equalling parameters.

To use your way of theory try this one : I have made a machine that measures the amount of coffee to put into a cup. Now I will test this along with one I make myself by hand.

Now I add the water and both are the same. Is the machine measured one equal all around the cup.

ONLY AFTER STIRRED.

p.s. I had to make a stirring modification on my coffee measurement machine and this cost me even more money. However I shall be selling said machine if anyone is interested. I'm going to return to using my hand to hold a spoon because it uses no electricity, doesn't cost anything and is equally effective if not even more than the machine method. p.m. me if you want the ressearch papers on this project 

I look forward to seeing you prove your theories on barrreport  See you there

AC


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