Question about pressurised CO2 and water disturbance

[5678]

To update on my tank, got home and the drop checker is a nice shade of light green. Not sure on the bubble rate for today though as the counter leaked.

Cheap ph pen is telling me I'm at ph 8.0 though! I'll try my api test kit and see what that says.

Fitted my new bubble counter and have it at 0.8bps.

I'm going to watch how the ph pen and drop checker behave over night and then let it run tomorrow before making any more adjustments.

Big clown, what sort of money do you need to spend for a reliable ph measuring device?

 

[Edward Courtney]

Hi, this is a good thread, thanks for kicking it off amateurfishkeeper.
What I'm getting here is that measuring ph with an electronic device is much more reliable than using a drop checker for measuring CO2, is that the general consensus? If that's the case then great, I like reliable accuracy and it's one less fiddly glass thingy hanging in my display!
I've used a ph controller on my reef system but that was for running a calcium reactor and balancing KH which is quite a different kettle of fish (excuse the pun).
When I reboot my system having converted it to high tech planted I'll be running it with a sump where the CO2 will be injected. I'm thinking about using a 70mm CO2 Bazooka positioned right in front of the intake for the return pump, the thought process being that the CO2 bubbles will be drawn into the impeller and diffused efficiently into the water column, like a CO2 reactor, before the water is returned to the display. The return pipe is at a depth of about 100mm below the water surface in the display but there will be a fair bit of surface agitation as the return pump will be running at 2000LPH and I'll have a Vortech MP10 in the display as well. Display is 100cm x 40cm x 50cm, 200L. Does that sound like a good plan to you guys?

 

[ian_m]

No the drop checker is much much better indicator if CO2 levels as it is isolated from all the pH affecting gunk in your tank water. pH pens are affected by being from Ebay/China, needing calibrating and other salts in the water causing false reading. Problem with drop checker is the delay of an hour or two before its colour settles.

 

[5678]

Thanks again Ian. The drop checker has stayed at green all evening so I will see where it is in the morning and then allow it to run again tomorrow with no more adjustments.

If I get home tomorrow and it's the same green I may up the bps ever so slightly and see how it is the next day.

 

[Jose]

only a sucker trusts these ph pens and they fail much quicker when you leave them in the tank, been there done that. binned it after a couple of months
http://www.ebay.co.uk/itm/like/3712...3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108
even if they are calibrated every time you use them

Ive been using mine for over a year. It barely needs calibrating and it goes off maybe 0.1 ph units every month or so. But obviously batteries have to be changed quite often.

Have you managed to get your tank algae free on toms recommendations yet?

Ive got a pretty algae free Tank yes. And I can say 98% of what Ive applied CO2-wise is from T. Barr. Even if I get algae is because Im just lazy or many other reasons.

tom also has wet/dry filters to keep o2 levels up and injects co2 into a needle wheel return pump which helps lower ph faster.
decent quality gear makes it much easier to get co2 just right, why else would tom barr use high end dual stage regs and high quality metering valves. his metering valve probably costs more than most peoples entire co2 system.

Yeap agree. Its not possible for everyone to achieve but you should try to get as near to that as you can if you have high light. My co2 takes 2-3 hours to get a 1 unit ph drop.

decent quality gear makes it much easier to get co2 just right, why else would tom barr use high end dual stage regs and high quality metering valves. his metering valve probably costs more than most peoples entire co2 system.

Its not only about cost. You can get the same results with things from co2art. You jut have to know how.

 

[Jose]

No the drop checker is much much better indicator if CO2 levels as it is isolated from all the pH affecting gunk in your tank water. pH pens are affected by being from Ebay/China, needing calibrating and other salts in the water causing false reading. Problem with drop checker is the delay of an hour or two before its colour settles.

I cant believe people still recommend dropcheckers. But hey up to everyone to decide for themselves. What is better? To use a two colour indicator (dropchecker) or a 0.1 pH unit indicator that has been calibrated? You could say a pH pen is 5 times at least more accurate and that without getting into the time delay factor of the d.c

People should buy the most expensive pH pen they can afford. Im just saying that Ive used a cheap one for a year and still use it. It works for me.

 

[Julian]

Ive been using mine for over a year. It barely needs calibrating and it goes off maybe 0.1 ph units every month or so. But obviously batteries have to be changed quite often.


Ive got a pretty algae free Tank yes. And I can say 98% of what Ive applied CO2-wise is from T. Barr. Even if I get algae is because Im just lazy or many other reasons.


Yeap agree. Its not possible for everyone to achieve but you should try to get as near to that as you can if you have high light. My co2 takes 2-3 hours to get a 1 unit ph drop.


Its not only about cost. You can get the same results with things from co2art. You jut have to know how.

How do you keep the yellow pH controller mounted onto the tank?

 

[Jose]

How do you keep the yellow pH controller mounted onto the tank?

Its not very neat. I use a pair of twizzers tied with cello tape to my ph pen and hang it on the rim of the tank. If you can afford something better go for it please. Ive recommended this one cause its as cheap as a d.c.

 

[Julian]

Its not very neat. I use a pair of twizzers tied with cello tape to my ph pen and hang it on the rim of the tank. If you can afford something better go for it please.

And do you leave it turned on all the time? Why not just put the cap back on and only use it when needed? Just curious.

 

[Jose]

And do you leave it turned on all the time? Why not just put the cap back on and only use it when needed? Just curious.

Because it takes sime time to stabilize once you put it in from fresh. Maybe 3-5minutes sometimes. This is why people think they dont work. They are just slower specially if battery is not fresh. Yes I keep it on most of the time. Once you know a ballpark of how many BPS you need then you can toss it and follow a D.C only if you feel the urge but Ive tried this and I doubt Im ever going back to a D.C.

Another option is to get a really good KH test kit which might be around £100+pH unit.

 

[5678]

Hmmm, odd one this morning.

Drop checker was still green, but the PH pen had shown an increase of 1 ph. This is confusing.

Even if the PH pen is not calibrated correctly, a relative rise of 1 ph is still a rise, no? There is significant surface agitation (I have an e701 at full speed and the spray bar 1" below the surface in a 50l tank) so it should have gone back to blue?

 

[Jose]

Even if the PH pen is not calibrated correctly, a relative rise of 1 ph is still a rise, no?

Yes, unless the pH pen is really messed up or you have some kind of electric current in your tank which I dont know the name for in english.

 

[Jose]

Drop checker was still green, but the PH pen had shown an increase of 1 ph. This is confusing.

Even if the PH pen is not calibrated correctly, a relative rise of 1 ph is still a rise, no? There is significant surface agitation (I have an e701 at full speed and the spray bar 1" below the surface in a 50l tank) so it should have gone back to blue?

Which do you reckon is right/more right?

 

[5678]

Which do you reckon is right/more right?

I'm not too sure!

I lean towards believing the PH pen more, but then I cannot get my head around how the drop checker, which is supposed to be isolated from external influences, does not tally up?

 

[ian_m]

I lean towards believing the PH pen more, but then I cannot get my head around how the drop checker, which is supposed to be isolated from external influences, does not tally up?

Provided you haven't contaminated the drop checker fluid it will be right and pH pen wrong. The absolute value of pH is being affected something else in the water. You are all heading down the Matrix of misleading numbers game. Hey my latest gadget reads 6.8 (or what ever) so something must be wrong, what must I do.....

If your water is soft the pH pen will be hopelessly wrong, I think you need at least 4KH before you should even consider a reading. Oh you don't know your KH so how can you trust your pH reading.....If you claim you know you KH from where ?? Most hobby test kits are really alkalinity test kits oh which rely on pH to read KH....see the circular Matrix of numbers.....

Your drop checker is indicating there is still residual CO2 in the water, fine no problem with that, you have gone to great effort getting CO2 in there, not a problem. My drop checker often stay green next morning depending on spray bar angle, air pump not being on, age of drop checker fluid etc etc. No problem. I take the drop checker out and within 1/2 an hour it is dark blue.

The only thing you can rely on with the pH pen is the rough differential change in pH of 1 unit drop. Some people need 1.5 pH drop or greater to get their drop checkers green. In a tank you cannot correlate the KH value with absolute value of pH as there is so much else going on in the tank. Luckily these things cause you to under read pH values (acidic) thus you get a 1 pH drop with only 20ppm CO2, so you under dose CO2 rather than overdose and kill your fish.

So in summary, aim for 1 pH drop due to CO2 at lights on as a good start, you will probably be under 30ppm CO2, so safe start there. Use this in conjunction with drop checker, plant health and fish activity to gauge CO2 levels. Don't rely on the numbers too much, use the numbers in conjunction with what you see and work on that.

 

[Jose]

Provided you haven't contaminated the drop checker fluid it will be right and pH pen wrong. The absolute value of pH is being affected something else in the water. You are all heading down the Matrix of misleading numbers game. Hey my latest gadget reads 6.8 (or what ever) so something must be wrong, what must I do.....

Which Matrix is real. The colours one or the numbers one. Most of the d.c fluids Ive owned never went back to theyr original colour. But a pH pen you can calibrate, a d.c you just trust. That without getting into the 4dkh solution in it and wether you make them yoursel.

The absolute value of pH is being affected something else in the water.

This is true and that is why we measure "pH drop" which will not be affected (at least not a lot) by other bases and sure not by an acid in the water. Why? Well if you have a water and you add acid to it, the starting pH will change but so will the kH, yet the "pH drop" will stay quite close to being 1 (for 30 ppms). So all that changes is your starting point (pH) which you can monitor every morning anyway.

Your drop checker is indicating there is still residual CO2 in the water, fine no problem with that, you have gone to great effort getting CO2 in there, not a problem. My drop checker often stay green next morning depending on spray bar angle, air pump not being on, age of drop checker fluid etc etc. No problem. I take the drop checker out and within 1/2 an hour it is dark blue.

If he wants to find out then he should leave the water being aerated for another day, or how long do you say the residual co2 might stay in there?

The only thing you can rely on with the pH pen is the rough differential change in pH of 1 unit drop. Some people need 1.5 pH drop or greater to get their drop checkers green. In a tank you cannot correlate the KH value with absolute value of pH as there is so much else going on in the tank. Luckily these things cause you to under read pH values (acidic) thus you get a 1 pH drop with only 20ppm CO2, so you under dose CO2 rather than overdose and kill your fish.

This is your misinterpretation of the science behind it Ian. The pH drop is normally between 1 and 1.4 yes but this has got more to do with the co2 in the equilibrium (which we cant measure). But I can tell you even so its much more accurate than a d.c.

So in summary, aim for 1 pH drop due to CO2 at lights on as a good start, you will probably be under 30ppm CO2, so safe start there. Use this in conjunction with drop checker, plant health and fish activity to gauge CO2 levels. Don't rely on the numbers too much, use the numbers in conjunction with what you see and work on that.

See, one thing we agree on 100%.

Ideally and this is what T Barr recommends: Youd measure pH drop needed until you see any sign of stress on your critters. Now say that is 1.4. You now know what you should be aiming for. Youve got your refference now. If you add an acid to the water or the kh changes then you should still aim for the same ph drop but the final ph value will be different as well as the starting value.

 

[Jose]

The only thing you can rely on with the pH pen is the rough differential change in pH of 1 unit drop. Some people need 1.5 pH drop or greater to get their drop checkers green. In a tank you cannot correlate the KH value with absolute value of pH as there is so much else going on in the tank. Luckily these things cause you to under read pH values (acidic) thus you get a 1 pH drop with only 20ppm CO2, so you under dose CO2 rather than overdose and kill your fish.

This is another great thing about this method. You wont gass your fish with a 1 ph drop but you are also most probably over 20 ppm which is not bad. Then you can add more co2 to change ph 0.1 units every time. Youll never be able to do this with shades of green and yellow. So you are more likely to gass fish with a d.c.

 

[5678]

Some excellent advice from you both that I greatly appreciate.

I'm learning more with each post you guys make and think I have a solid set of information to work from.

One thing I may try, is to leave my tank without co2 until the drop checker goes blue and get my relative ph reading at that point.

 

[5678]

Looks like some element of success yesterday.

I recalibrated the PH pen (for what its worth!) and measured the following:
0640 7.6 DC Green
1425 7.4 DC Blue/Green (co2 had been on for approx 60 mins)
(lights on at 1430)
1745 6.9 DC Green (also swapped the JBL DC for a pretty glass one! upped the bps a fraction.)
1930 6.7 DC Green
(co2 off at 2030)
2210 7.3 DC Dark Green

Then this morning:
0650 7.8 DC Blue

So it seems I'm not too far off with things now?

Annoyingly I broke the diffuser last night so I've turned co2 and lights off for today.

I changed the angle of my spray bar ever so slightly to increase surface agitation which seems to have worked with gassing off over night. I am still seeing all plants swaying though.

I'm planning to run this for a few days to try and make sure I get the DC green and the PH around 6.8/6.7 by lights on by adjusting the co2 on time.

 

[Jose]

1745 6.9 DC Green (also swapped the JBL DC for a pretty glass one! upped the bps a fraction.)
1930 6.7 DC Green

See? A 0.2 pH change and I doubt you can see the change in colour of the d.c. All it takes to gas your fish is a 0.1 ph change and even less. You cant really know if youre anywhere near without measuring pH.

I think youre doing well by using both methods, because its all about the confidence and experience on what works.