I'd agree with FN, the least you have to do to artificially change your tank conditions the better.
increasing kH before injecting co2?
- Thread starter kooter
- Start date
Please do not add coral to somethng with a KH of 2. It is perfect the way it is. You shouldn't tamper with your water chemistry when there is nothing wrong with it.
Due to CO2, your pH will fluctuate about .4 going between 10-30ppm CO2 with a KH of 4. With a KH of only 1, you ph fluctuation will be about .5. I doubt an extra .1 swing is going to be significant.
Lets say more of an extreme. Some push thier co2 levels up to 40ppm. The biggest swing I could think of would be a total gas-off of all CO2 over ambient, which is usually 5ppm or less. So lets compare the pH swing from 5ppm-40ppm CO2, with KH of 1 compared to a KH of 4, or actually lets use 6 to get even more 'buffering effect'.
KH=1, CO2=40, pH=5.9
KH=1, CO2=5, pH=6.8
So with KH of 1, we have a pH swing of .9
KH=6, CO2=40, pH=6.7
KH=6, CO2=5, pH=7.5
So with a KH of 6, we have a pH swing of .8
Again, there seems to be only a difference of .1 in the pH swing going from extreme CO2 fluctuation and across almost no KH to a high amount. Not enough to worry much about. I am trying to remember one thing to worry about though, I forget what its called exactly, something like biogenic decalcification. As I recal if you cant meet the carbon requirment of plants, some plants can utilize the KH in the water for carbon, which can cause major problems and calcium can percipitate over everthing reuining the tank, filters, heater, etc. So make sure them plants get enough co2!
Lets say more of an extreme. Some push thier co2 levels up to 40ppm. The biggest swing I could think of would be a total gas-off of all CO2 over ambient, which is usually 5ppm or less. So lets compare the pH swing from 5ppm-40ppm CO2, with KH of 1 compared to a KH of 4, or actually lets use 6 to get even more 'buffering effect'.
KH=1, CO2=40, pH=5.9
KH=1, CO2=5, pH=6.8
So with KH of 1, we have a pH swing of .9
KH=6, CO2=40, pH=6.7
KH=6, CO2=5, pH=7.5
So with a KH of 6, we have a pH swing of .8
Again, there seems to be only a difference of .1 in the pH swing going from extreme CO2 fluctuation and across almost no KH to a high amount. Not enough to worry much about. I am trying to remember one thing to worry about though, I forget what its called exactly, something like biogenic decalcification. As I recal if you cant meet the carbon requirment of plants, some plants can utilize the KH in the water for carbon, which can cause major problems and calcium can percipitate over everthing reuining the tank, filters, heater, etc. So make sure them plants get enough co2!
It is simple chemistry guys- the lower the kh, the less resistant to changes in pH water will be as acids are added. Over time the nitrogen cycle will cause pH to drop, something water changes help to prevent.
When one adds co2 to a tank, as it disolves in the water some of it forms carbonic acid. This is why kh is relevant.
But dont take my word for it go read any of these sites
A mirror site for thekrib.com
http://fins.actwin.com/aquariafaq.html
Aqua - Center
http://www.drhelm.com/aquarium/chemistry.html
More technical explanation at Chemistry.org
http://www.chemistry.org/portal/a/c/s/1/feature_ent.html?id=16c4caa0350211d6eba74fd8fe800100
The only place I could find that says low kh is not a problem was Chuck's Planted Aquarium Pages
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
Basically, one can calculate the amount of pH change for a given change in kh. If you start with a kh of 2 and reduce it to 1, that 1dg change should result in a pH change of -.69. (Note 1dg is a change of 50%), If you start with a kh of 8 and reduce it by 1dg to 7, that 1 dg change should result in a pH change of -.13. However, if you start at kh 8 and reduce it by 50%, or 4dg, the resulting pH change is -.69.
(source: http://www.dataguru.org/misc/aquarium/calKH.asp )
The problem is if you start with a kh of 2dg and reduce it by 4dg....... oops.
Kooter- I would just keep an eye on your levels when you first start up your injection of co2. If everything stays in line, great. If not, you will know fast enough to deal with any problems.
When one adds co2 to a tank, as it disolves in the water some of it forms carbonic acid. This is why kh is relevant.
But dont take my word for it go read any of these sites
A mirror site for thekrib.com
http://fins.actwin.com/aquariafaq.html
Aqua - Center
http://www.drhelm.com/aquarium/chemistry.html
More technical explanation at Chemistry.org
http://www.chemistry.org/portal/a/c/s/1/feature_ent.html?id=16c4caa0350211d6eba74fd8fe800100
The only place I could find that says low kh is not a problem was Chuck's Planted Aquarium Pages
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
Basically, one can calculate the amount of pH change for a given change in kh. If you start with a kh of 2 and reduce it to 1, that 1dg change should result in a pH change of -.69. (Note 1dg is a change of 50%), If you start with a kh of 8 and reduce it by 1dg to 7, that 1 dg change should result in a pH change of -.13. However, if you start at kh 8 and reduce it by 50%, or 4dg, the resulting pH change is -.69.
(source: http://www.dataguru.org/misc/aquarium/calKH.asp )
The problem is if you start with a kh of 2dg and reduce it by 4dg....... oops.
Kooter- I would just keep an eye on your levels when you first start up your injection of co2. If everything stays in line, great. If not, you will know fast enough to deal with any problems.
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I am not smart enough to add to this conversation but then again I am not smart enough to stay out of it either.
If you look at a chart you will see that it gets harder to maintain ppm CO2 the lower the kh. If the kh is low in the first place adding some along with the CO2 would seem to make the process a lot easier.
http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html
That said I have never actually heard of anyone crashing the ph. I have heard a lot of people say it would happen but I have never actually seen anyone claim (maybe that should be clam) it did.
http://en.wikipedia.org/wiki/Carbonic_acid
If you look at a chart you will see that it gets harder to maintain ppm CO2 the lower the kh. If the kh is low in the first place adding some along with the CO2 would seem to make the process a lot easier.
http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html
That said I have never actually heard of anyone crashing the ph. I have heard a lot of people say it would happen but I have never actually seen anyone claim (maybe that should be clam) it did.
http://en.wikipedia.org/wiki/Carbonic_acid
I am surprised FN didnt link to these threads, but anyway here is a good read: http://www.plantedtank.net/forums/general-planted-tank-discussion/32365-low-no-kh-low-ph-without.html?highlight=crash and
http://www.plantedtank.net/forums/general-planted-tank-discussion/35622-our-low-kh-experiment-lets-update.html?highlight=co2+crash+myth
I beleive keeping the KH up is more of a bandaid for some other problems. CO2 alone shouldnt cause any problems in the levels we use.
IMO that chart on the Krib is pretty outdated. For one, the lowest it goes is a ph of 6.7, for most planted tanks the ph doesnt get above that number. Also KH really has little or no effect on maintaining co2 levels. I think you miss ineterpreted what you were reading on that chart. How much co2 you inject determines your co2 levels, KH makes no difference (also the water temp, effeciency of your difuser, surface agitation, etc. effect co2).
http://www.plantedtank.net/forums/general-planted-tank-discussion/35622-our-low-kh-experiment-lets-update.html?highlight=co2+crash+myth
I beleive keeping the KH up is more of a bandaid for some other problems. CO2 alone shouldnt cause any problems in the levels we use.
IMO that chart on the Krib is pretty outdated. For one, the lowest it goes is a ph of 6.7, for most planted tanks the ph doesnt get above that number. Also KH really has little or no effect on maintaining co2 levels. I think you miss ineterpreted what you were reading on that chart. How much co2 you inject determines your co2 levels, KH makes no difference (also the water temp, effeciency of your difuser, surface agitation, etc. effect co2).
hey loaches...I didn't reference the threads because I didn't want this to turn into another fight or debate.
Bottom line is ...the old school of thought which was based on theory and some catch phrases....<like pH crash>
and the new school of thought which is something we have in working practice....lower kH is GREAT...plants love it, fish love it....the aquarist loves it because there is minimal manipulation.....and voila....
The key is water movement <oxygenation>
That is it. I still have a KH of 1...my pH stays at 6 or lower at times...and my plants thrive and my fish thrive.
I add nothing but my ferts...and CO2..
People with water like rock...i.e. hard water high GH KH WISH for water that you have...so if it aint broke...don't fix it.:idea:
Bottom line is ...the old school of thought which was based on theory and some catch phrases....<like pH crash>
and the new school of thought which is something we have in working practice....lower kH is GREAT...plants love it, fish love it....the aquarist loves it because there is minimal manipulation.....and voila....
The key is water movement <oxygenation>
That is it. I still have a KH of 1...my pH stays at 6 or lower at times...and my plants thrive and my fish thrive.
I add nothing but my ferts...and CO2..
People with water like rock...i.e. hard water high GH KH WISH for water that you have...so if it aint broke...don't fix it.:idea:
No prob, I have linked them many times. I usually just post the links, and let folks make thier own call.
