So, I'm not asking this because I think that alkalinity magically shows up. I know it's coming from somewhere, and ultimately I'm just trying to figure out where it is. And even more ultimately, I'm trying to understand how alkalinity really interacts with different water conditions so that I can better understand what my tank is trying to tell me.
A few weeks ago I had a major RTN event that killed most of the coral in my tank. Since then I've been actively... not dosing, because I think a contributing factor to that event was an elevated ALK level.
It's been falling steadily since then (exactly as one would expect), until recently, when it started rising again. For about the last week, I've been seeing a 0.1 dKh increase per day when comparing measurements at the same time on consecutive days. I'm not dosing anything that should add alkalinity. So where is that measured alkalinity coming from?
To give some context:
First, the measurements are coming from my Trident. I recently changed the Alk reagent and have verified its results with my Hanna checker, which is also working with fresh reagent. The measurements between the two devices are within the known MoE for both tests - they don't agree completely, but their disagreement falls within their mutual error bars.
Second, the large-scale coral deaths are mostly over, but I have still continued losing some corals. I have mostly removed the skeletons of expired corals, but there are still some in the tank.
Third, after cleaning some of my internal powerheads, flow inside the tank has increased. This has resulted in more sand than usual being stirred up and blown around the tank. I also have a leopard wrasse who loves to stir up the sand.
Fourth, I've started using the Hygger aquarium brush to clean off my rockwork. When I do this, it has stirred up significant amounts of particulates into the water column.
Fifth, my tank has had persistent very high pH. Over the past month, my average pH has been around 8.55, with a peak value of 8.7 and a low of 8.3. I'll allow that this could be measurement error, but I do have high levels of unwanted algae (display tank) and wanted algae (refugium + ATS) so even without a huge coral load there is a lot of photosynthesis going on in the tank.
Finally, I just added a protein skimmer back into my tank this last week.
So, where is the rising alkalinity measurement likely coming from?
I'm not worried about this in the sense that I think it's going to crash my tank. My tank already crashed, so there's not really much to worry about there. It's more a curiosity, about what is it that's causing that measurement to increase despite not actively dosing anything that should cause it to increase.
I don't think it's water changes, just to head that off before it's suggested - the rise started before my most recent water change and continued after it at the same pace as it was going before. Yes, there was an expected jump directly after the water change, but then the rise continued afterwards.
A few weeks ago I had a major RTN event that killed most of the coral in my tank. Since then I've been actively... not dosing, because I think a contributing factor to that event was an elevated ALK level.
It's been falling steadily since then (exactly as one would expect), until recently, when it started rising again. For about the last week, I've been seeing a 0.1 dKh increase per day when comparing measurements at the same time on consecutive days. I'm not dosing anything that should add alkalinity. So where is that measured alkalinity coming from?
To give some context:
First, the measurements are coming from my Trident. I recently changed the Alk reagent and have verified its results with my Hanna checker, which is also working with fresh reagent. The measurements between the two devices are within the known MoE for both tests - they don't agree completely, but their disagreement falls within their mutual error bars.
Second, the large-scale coral deaths are mostly over, but I have still continued losing some corals. I have mostly removed the skeletons of expired corals, but there are still some in the tank.
Third, after cleaning some of my internal powerheads, flow inside the tank has increased. This has resulted in more sand than usual being stirred up and blown around the tank. I also have a leopard wrasse who loves to stir up the sand.
Fourth, I've started using the Hygger aquarium brush to clean off my rockwork. When I do this, it has stirred up significant amounts of particulates into the water column.
Fifth, my tank has had persistent very high pH. Over the past month, my average pH has been around 8.55, with a peak value of 8.7 and a low of 8.3. I'll allow that this could be measurement error, but I do have high levels of unwanted algae (display tank) and wanted algae (refugium + ATS) so even without a huge coral load there is a lot of photosynthesis going on in the tank.
Finally, I just added a protein skimmer back into my tank this last week.
So, where is the rising alkalinity measurement likely coming from?
I'm not worried about this in the sense that I think it's going to crash my tank. My tank already crashed, so there's not really much to worry about there. It's more a curiosity, about what is it that's causing that measurement to increase despite not actively dosing anything that should cause it to increase.
I don't think it's water changes, just to head that off before it's suggested - the rise started before my most recent water change and continued after it at the same pace as it was going before. Yes, there was an expected jump directly after the water change, but then the rise continued afterwards.
