have you ever had a "pH crash", and what was it like?
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Crepe
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Never had a pH crash. The water in my tap is liquid lime so never had buffering issues. But you can adversely change your pH by putting a hood on a previously uncovered tank.
Crepe
Aquarium Advice Addict
A hood limits gas exchange, which can cause your pH to become too low. I know this is a bigger issue in SW than in FW.
Crepe
Aquarium Advice Addict
To my knowledge kH is very very hard to make 0. Not only do you need to either outgas what you have but also any dissolved mineral bases have to be neutralized. In other words you need a lots of acid.
CO2 is in constant equilibrium with the atmosphere. When you put a hood on you limit the volume of the tank and therefore limit the movement of gas particles. Instead of outgassing into the the atmosphere, they return to the water.
The gas in question that affects pH the most is CO2 due to the H2CO3 <-->Co2 + H2O reaction that is also the buffer in our own blood. The conditions that can cause a pH crash are generally not chemical but physical. Reduced water circulation and surface agitation and the limitation of gas movement.
It is in theory possible to have a pH crash due to ammonia spikes but this requires a LOT of ammonia, enough to cause all your livestock, excluding plants, to die before pH is even a question.
CO2 is in constant equilibrium with the atmosphere. When you put a hood on you limit the volume of the tank and therefore limit the movement of gas particles. Instead of outgassing into the the atmosphere, they return to the water.
The gas in question that affects pH the most is CO2 due to the H2CO3 <-->Co2 + H2O reaction that is also the buffer in our own blood. The conditions that can cause a pH crash are generally not chemical but physical. Reduced water circulation and surface agitation and the limitation of gas movement.
It is in theory possible to have a pH crash due to ammonia spikes but this requires a LOT of ammonia, enough to cause all your livestock, excluding plants, to die before pH is even a question.
Quoting thekrib (reflective of my current knowlege)...
"When the aquarium has some carbonate buffering in it, the bicarbonate ions will combine with the excess hydrogen ions to form carbonic acid (H2CO3) which then slowly breaks down into CO2 and water. Since the excess hydrogen ions are used in the reaction, the pH does not change very much. Over time, as the carbonate ions are used up, the buffering capacity will drop and larger pH changes will be noted. From this it is clear why aquariums with low KH seem unstable -as acid is produced by biological action, the KH is used up; when it is gone, the pH is free to drop rapidly as H+ ions are generated."
--end quote (from http:// aquaticconcepts.thekrib.com/Articles/ Water_Chemistry.htm ; copyright 2000 George and Karla Booth)
So what else do we know now, as technology and science have advanced over the several years period (more than a decade) between the time when that was writen and today?
What more can anyone add to that? The replies we've seen in this thread thus far don't take us much further than the above cited article. Is there more to be known?
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"When the aquarium has some carbonate buffering in it, the bicarbonate ions will combine with the excess hydrogen ions to form carbonic acid (H2CO3) which then slowly breaks down into CO2 and water. Since the excess hydrogen ions are used in the reaction, the pH does not change very much. Over time, as the carbonate ions are used up, the buffering capacity will drop and larger pH changes will be noted. From this it is clear why aquariums with low KH seem unstable -as acid is produced by biological action, the KH is used up; when it is gone, the pH is free to drop rapidly as H+ ions are generated."
--end quote (from http:// aquaticconcepts.thekrib.com/Articles/ Water_Chemistry.htm ; copyright 2000 George and Karla Booth)
So what else do we know now, as technology and science have advanced over the several years period (more than a decade) between the time when that was writen and today?
What more can anyone add to that? The replies we've seen in this thread thus far don't take us much further than the above cited article. Is there more to be known?
Sent from my Droid using Aquarium Advice App
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