not sure this is posted in the right forum water kh etc

[dazzer1975]

ive just tested the kh and it is 30ppm (previously 20ppm) which is around 1.7 to 2 degrees hardness and the ph is 6.6 -6.8 which means the co2 is around the 10ppm mark. When I first started with the co2 I didnt use any sort of kh raising agent or buffer and the ph dropped to 6.2 - 6.4.

Since then I have been slowly adding small pieces of tuffa rock to the tank, now the amount of tuffa rock has been increased in the tank as has the diy yeast generation, alongside the 2 hagen diy units, i have also set up a 2 litre coke bottle and thats running into the tank also.

The kh has risen by 10ppm and presumably, the amount of dissolved co2 has increased so therefore the buffering is doing it's job by keeping the ph in the required range and stable while allowing a higher co2 content? Therefore using the ph to kh ratio will not give me an accurate measure of co2?

Lets assume the co2 has in fact risen and the tuffa is helping to buffer the ph from crashing then could the resulting carbonic acid be the cause of the (slightly) increased kh while keeping the ratio between kh and ph as signifying low levels of co2?

In other words, would using the relationship between the ph and
the kh to work out the co2 content be more innacurate than usual?

If those wafflings can be followed I would be interested in ideas!

p.s. the wisteria was also throwing out a long stream of o2 bubbles last night which prompted me to wonder about the co2 and kh etc. Here's a pic of the wisteria where you can make out the bubble stream

 

[Martin]

Re: not sure this is posted in the right forum water kh etc

ive just tested the kh and it is 30ppm (previously 20ppm) which is around 1.7 to 2 degrees hardness and the ph is 6.6 -6.8 which means the co2 is around the 10ppm mark. When I first started with the co2 I didnt use any sort of kh raising agent or buffer and the ph dropped to 6.2 - 6.4.

Since then I have been slowly adding small pieces of tuffa rock to the tank, now the amount of tuffa rock has been increased in the tank as has the diy yeast generation, alongside the 2 hagen diy units, i have also set up a 2 litre coke bottle and thats running into the tank also.

The kh has risen by 10ppm and presumably, the amount of dissolved co2 has increased so therefore the buffering is doing it's job by keeping the ph in the required range and stable while allowing a higher co2 content? Therefore using the ph to kh ratio will not give me an accurate measure of co2?

Lets assume the co2 has in fact risen and the tuffa is helping to buffer the ph from crashing then could the resulting carbonic acid be the cause of the (slightly) increased kh while keeping the ratio between kh and ph as signifying low levels of co2?

In other words, would using the relationship between the ph and
the kh to work out the co2 content be more innacurate than usual?

If those wafflings can be followed I would be interested in ideas!

p.s. the wisteria was also throwing out a long stream of o2 bubbles last night which prompted me to wonder about the co2 and kh etc. Here's a pic of the wisteria where you can make out the bubble stream

It's hard to follow your line of thoughts when you do not post your pH. I would assume that the tuffa stone raises the kH like baking soda, and thereby increased the buffering capabilities of the water, and thus prevent pH crash. Now I'm pretty suer that your pH drops slightly when you add Co2, but the lH prevents the crash you mention.
Test your pH according to your theory and see what you come up with.

 

[dazzer1975]

Re: not sure this is posted in the right forum water kh etc

hi symbiot,

the ph was on the second line, although I appreciate that my style of writing in the post concerned made it hard to follow.

The p.h. is reading as 6.6 - 6.8 which I am happy with.

My problem is that I have added an additional diy co2 producer and when using chuck gadds co2 calculator the readings are still showing at around the 10ppm for co2.

I am working under the presumption that as I have increased the co2 going into the tank (albeit in a diy method) that the dissolved co2 should/would have increased.

However, the readings dont seem to confirm this and I was wondering if the tuffa rock and resultant (slightly increased) kh could impact upon the accuracy of using a co2 calculator as opposed to directly testing the water for co2 specifically?

I apologise for not explaining properly but I am still grappling with all this science stuff myself.

T.I.A.

 

[Martin]

Re: not sure this is posted in the right forum water kh etc

hi symbiot,

the ph was on the second line, although I appreciate that my style of writing in the post concerned made it hard to follow.

The p.h. is reading as 6.6 - 6.8 which I am happy with.

My problem is that I have added an additional diy co2 producer and when using chuck gadds co2 calculator the readings are still showing at around the 10ppm for co2.

I am working under the presumption that as I have increased the co2 going into the tank (albeit in a diy method) that the dissolved co2 should/would have increased.

However, the readings dont seem to confirm this and I was wondering if the tuffa rock and resultant (slightly increased) kh could impact upon the accuracy of using a co2 calculator as opposed to directly testing the water for co2 specifically?

I apologise for not explaining properly but I am still grappling with all this science stuff myself.

T.I.A.

My mistake on the pH.
what's you kH in degree's now? about 3 or so? "Easiest" would be to add enough buffer til land you around a kH of 10'ish. Perhaps using Baking soda would be easier?
I'd test the water just to check it against the chart.

 

[Tom Barr]

Re: not sure this is posted in the right forum water kh etc

A KH of 20ppm is still fine, 30-40ppm is fine also.
I generally will not add KH unless it's less than 20ppm.

I've done tanks with no KH also, but had to add the KH to get a ball park range of CO2, then removed all the KH later.

You may just need to add more CO2 is all and the accuracy of the pH test kit might be part of the issue. A pH pen or pH monitor might be a wise item to get. also, make sure to turn off any electrical devices before taking a reading and calibrate the probe often.

Do not just measure once either, measure several times thoughout one day to see how the CO2 vary over a typical day(measure just when the lights and CO2 are on).

Afterwards, this will give a fairly good idea what the CO2 is doing and you can predict what ranges the CO2 is. then you will not need to test much again so much unless there is a problem with algae, or plant growth slows down dramatically etc. Then the pH pen/monitors make a quick spot check from then on fairly easy and quick.

Do not think of a any measurement, CO2 in particular of all the measurement test we do, as a stable level throughout the day. It varies, so just seeing one point in time does not tell you that much. It's more work to test every 1-2 hours, but it does give you a much better idea of the patterns with CO2.

It's not something I'd suggest you do as a routine though.
Many folks assume their CO2/opH is the saem if they take one single measurement and post that, some folks post a range of pH's for the day(better).

Now that is just day variation, add week variation or monthly variations and folks can have a very wide difference.

If the CO2 is stable over the month etc, then you have pretty nice growth and little/no algae.


Regards,
Tom Barr

 

[dazzer1975]

Re: not sure this is posted in the right forum water kh etc

Ah yes, obviously the co2 readings should vary over the day, I never thought about that.

Thanks very much Tom Ill get started on compiling a set of tests at various times.

Cheers!

P.S. a pressurised system is definitely on the cards for the future

 

[Tom Barr]

Re: not sure this is posted in the right forum water kh etc

Well, canned gas tank CO2 is really the only way to go unless it's 10-20gal and such.

It does make a world of difference in the control and stability of the CO2.
If there is one thing folks should splurge on, it's this.

After folks get it, they always ask "Damn, why didn't I do this years ago?"
Few would argue with that statement.

People drop 200$ for lighting and seldom balk that much finanically. CO2 is sketchy to them on the other hand and there's the alternative DIY, which does work, but the trade off is a lack of stablity and flow control and use for larger tanks.

Test the pH, at say 0 hours, 1 hour, 4, 8 and right before the lights go off.

Regards,
Tom Barr

 

[dazzer1975]

Re: not sure this is posted in the right forum water kh etc

Thanks Tom, (Again)

I have just ordered the jbl proflora vario 500 profi set 2 so once that gets here I should be good to go.

The substrate is still silica sand with fertiliser tabs placed in there. I wont be updating the substrate on that tank unless I pull it all apart and start from scratch.

However, I have just set up a small 10 gallon tank to grow rear some fry and used flourite for that substrate. I may experiment with different substrates in the future, this is really exciting and interesting, people use peat, soil, gravels, cactus potting compost etc etc, the list seems endless