For my ~35L shrimp tank, I decided to add some activated carbon that I had stored. I used some wood pieces for the decoration and the water has always been yellow since the first days, almost 2 years ago.
Since this tank isn't exactly thriving, I've been slowly testing and adjusting as I see fit, and this carbon test has been on the list for a while. It could even be expanded to my other tanks as well, if things were to improve.
One day after adding a good pack of carbon to the canister, which now in hindsight may have been an exaggerated quantity, the water was clear, but I found a dead caridina. I don't do this often, but I decided to do a round of tests to check if anything had changed, and what I found is that the pH raised from ~6.6 to over 7.6, which is the limit of the scale for my test. KH remains unchanged (something between 0.5 and 1dKH). I thought that maybe with the removal of the tannins which were possibly reducing the pH, it could rise a little, but nothing like this. And considering the low KH, it all seemed very curious.
So after a brief online search, I found that it is very common for activated carbon to raise the pH. One site, from a supplier of carbon, says that no one really knows why this happens, but it is often associated with the presence of ash content in the carbon. And that the pH could raise up to 3 points! And these effects would diminish after 100 to 1000 bed volumes of water processed. I don't really know what that means, but it sounds like a lot of water.
I had never heard any of that before in my aquarium circles, but most people seem to have left activated carbon behind, nowadays.
So my question is, was this expected? Should I just give up on this and maybe buy purigen? This all happened Saturday, so a few days ago, and apparently only that first caridina died, and maybe it was unrelated.
Since this tank isn't exactly thriving, I've been slowly testing and adjusting as I see fit, and this carbon test has been on the list for a while. It could even be expanded to my other tanks as well, if things were to improve.
One day after adding a good pack of carbon to the canister, which now in hindsight may have been an exaggerated quantity, the water was clear, but I found a dead caridina. I don't do this often, but I decided to do a round of tests to check if anything had changed, and what I found is that the pH raised from ~6.6 to over 7.6, which is the limit of the scale for my test. KH remains unchanged (something between 0.5 and 1dKH). I thought that maybe with the removal of the tannins which were possibly reducing the pH, it could rise a little, but nothing like this. And considering the low KH, it all seemed very curious.
So after a brief online search, I found that it is very common for activated carbon to raise the pH. One site, from a supplier of carbon, says that no one really knows why this happens, but it is often associated with the presence of ash content in the carbon. And that the pH could raise up to 3 points! And these effects would diminish after 100 to 1000 bed volumes of water processed. I don't really know what that means, but it sounds like a lot of water.
I had never heard any of that before in my aquarium circles, but most people seem to have left activated carbon behind, nowadays.
So my question is, was this expected? Should I just give up on this and maybe buy purigen? This all happened Saturday, so a few days ago, and apparently only that first caridina died, and maybe it was unrelated.
