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pH pens and low KH

GlassWalker said:
I found a method to monitor the spectral absorption of CO2 which sounds like a likely candidate to be used here.
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Spectral absorption probes already are available and cost lots of money. Mass spectrometry is one of the techniques used in £1000 equipment.

Cheers,
 
The point of that kickstarter was to develop a unit at a more affordable price for use in planted aquaria. I didn't sign up for it, but recall some on another forum who did so will wait to see how it performs. If it is any good, I can consider getting one later.
 
$125-200 lasting a year or two, plus you need a pH meter to plug it into... doesn't get me excited! The other CO2 monitor I linked to I think has more long term potential, assuming it performs to expectations.
 
Thanks for all the input guys.

I've always thought that it would be great to have a more accurate drop checker. What I mean by that is one similar to the JBL one, but with a very precise colour chart which indicates the estimated Co2 level in PPM. So you could compare the colour of the bromo to the colours behind it and check the PPM of Co2.
 
Hi all,
Sacha said:
I've always thought that it would be great to have a more accurate drop checker. What I mean by that is one similar to the JBL one, but with a very precise colour chart which indicates the estimated Co2 level in PPM. So you could compare the colour of the bromo to the colours behind it and check the PPM of Co2.
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You could make your own colour chart using the pH indicator chart for bromothymol blue and CO2/dKH/pH chart. Something like the CalAquaLabs one, but with actual figures.
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cheers Darrel
 
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You already have an accurate drop checker.... Your plants. Ppm is pretty irrelevant if your plants are failing... Play with co2 and flow until your tank is going the way you want.
While I can see some use for a co2 devise I can also see the innumerable number of threads created by being tunnel visioned by it and still having issues (same as drop checkers now)
 
So how would you go about measuring the CO2 concentration in an aquarium. For example I have a kH of 9 and a pH of 7 and after 1 hour I have a pH of 6.5...what would be approximately my CO2 ppm then?

ceg4048 said:
No, you are missing a couple of key points. The charts are a very rough guide because they assume that the KH of the water is due to Carbonates - and that's not really true for most tap water. Your KH test kit does NOT measure KH, it measure alkalinity which is affected by a lot more ions than Carbonate. So right off the bat there is n overestimate of CO2 concentration on the charts. You will never have the opposite situation where the charts underestimates the CO2 concentration level. The second issue is that the pH readings are corrupted by acids in the water so the pH reading again, always overestimates the CO2 concentration.

So, both parameters are overestimates and that's why you're mistakenly assuming that we're adding well over 30 ppm. The 1 unit pH drop for medium to medium-high KH readings is about as good an estimate as we can get because no one knows exactly how much the non-Carbonate ions are contributing to the KH reading but generally that difference accounts for the error.


Cheers,
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Please review Iain Sutherland's response in post #27. If the plants are dying then the CO2 concentration is too low. If they are thriving then the CO2 concentration is high, if they are doing fair to middling then the CO2 concentration is fair to middling. The number is irrelevant. We only use the numbers as a guide. We only use the DC as a guide. No number and no DC can tell you more than you can see with your own two eyeballs.

Cheers,
 
ceg4048 said:
Please review Iain Sutherland's response in post #27. If the plants are dying then the CO2 concentration is too low. If they are thriving then the CO2 concentration is high, if they are doing fair to middling then the CO2 concentration is fair to middling. The number is irrelevant. We only use the numbers as a guide. We only use the DC as a guide. No number and no DC can tell you more than you can see with your own two eyeballs.

Cheers,
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Can you suggest a reasonably priced good ph pen?
 
ceg4048 said:
If the plants are dying then the CO2 concentration is too low.
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There is a real danger of people reading and interpreting this statement in isolation. It gives the impression that CO2 concentration is everything. That clearly is not the case. I signed up to this community because I want to better understand the science behind successful growing of aquatic plants. On a personal level, I am not strong enough to get embroiled in arguments. I just wish we could discuss things on an equal terms basis.

There is no evidence to suggest that insufficient CO2 is an issue in the problem that I have been recently reporting.

JPC
 
Jaap said:
Can you suggest a reasonably priced good ph pen?
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Hi Jaap,

Today, I took delivery of an HM Digital PH-200 pH pen. Please take a look at:

http://www.tdsmeter.com/products/ph200.html

It is too soon to say that I made the right choice - so watch this space!

When you say 'reasonably priced', what did you have in mind? It has to be said that pH meters are, by their very nature, complex pieces of kit. It is possible to pay very little for a pH meter but its accuracy is not likely to be particularly good. If, for example an accuracy of +/- 0.2pH meets your needs, then select one accordingly. If auto-calibration is important to you, then add that to your requirements specification. Also, be aware that the sensing part of a pH meter - the pH electrode - may give you just 18 months' service after which it will need to be replaced. So, choose a meter that will enable you to do this. If you take a look at the above link, it will hopefully give you some ideas of what you need to consider.

JPC
 
John P Coates said:
Hi Jaap,

Today, I took delivery of an HM Digital PH-200 pH pen. Please take a look at:

http://www.tdsmeter.com/products/ph200.html

It is too soon to say that I made the right choice - so watch this space!

When you say 'reasonably priced', what did you have in mind? It has to be said that pH meters are, by their very nature, complex pieces of kit. It is possible to pay very little for a pH meter but its accuracy is not likely to be particularly good. If, for example an accuracy of +/- 0.2pH meets your needs, then select one accordingly. If auto-calibration is important to you, then add that to your requirements specification. Also, be aware that the sensing part of a pH meter - the pH electrode - may give you just 18 months' service after which it will need to be replaced. So, choose a meter that will enable you to do this. If you take a look at the above link, it will hopefully give you some ideas of what you need to consider.

JPC
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Would you use it to measure ph reliably?

Would you use it to measure pars?
 
Jaap said:
Would you use it to measure ph reliably?

Would you use it to measure pars?
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Hi Jaap,

As I said, it is too soon to know just how reliable the PH-200 is.

I don't understand your second question. By 'pars', are you referring to lighting? The PH-200 measures pH and temperature but not lighting.

JPC
 
John P Coates said:
Hi Jaap,

As I said, it is too soon to know just how reliable the PH-200 is.

I don't understand your second question. By 'pars', are you referring to lighting? The PH-200 measures pH and temperature but not lighting.

JPC
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I m sorry i messed up the threads...both questions were for the seneye?
 
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