The system is a mature, densely packed SPS tank.
The system previously ran a base pH of 8.2 and went as high as 8.5 at the end of the light cycle on weekends when no one was in the office. I would say on avg, it topped out in the 8.4 to 8.45 range when the space was occupied with people.
Alk is typically 8.5 dkh.
I dose Kalk at night and I have an ERV unit to cycle the inside and outside air.
C02 in the room ranges from 450 (more or less ambient) to low 600's depending on how many people are in the office.
Here are the changes I've noticed.
pH tops out at around 8.25 during the day now and holds steady there until the lights go off. It peaks at 8.25 around 1pm and then just parks there until the tank goes dark.
I was dosing 4 liters of Kalk at night to maintain a floor of 8.2 and now I'm dosing 8 liters of Kalk at night and it barely gets up to 8.18.
The pH of the Kalk is around 12.5, so I assume it's fully saturated. I always pour more Kalk powder in than necessary when making a batch as insurance. I keep it in a 55g sealed plastic drum.
I was dosing 400ml/day of Alk and Ca to maintain the 8.5dkh and 450ppm Ca parameters, now the tank is only asking for 250ml/day to maintain the same numbers.
To be sure the pH readings were correct, I calibrated my Apex pH probe. Didn't end up needing as it was reading correctly in 7 and 10 solutions, but did it anyway.
I also co-witnessed the Apex's pH readings by using a separate standalone pH meter (Apera).
The tank looks pretty good overall still, but growth has really slowed. A lot. When the tank was consuming 400ml per day and the pH was getting up to the low 8.4's, you could literally see daily growth in a lot of the corals. Albeit small, it was noticeable. But the growth was really was adding up over weeks and months.
The only thing I've changed recently with the routine is I upped the nutrients in the tank. I thought I was running 0.08 Phos and 5-7 nitrates, but the ICP test kept coming back that the phosphates were zero or 0.01ppm. Which explains why some of the acros were looking kind of muted in terms of color.
So I upped the feeding regimen and put the phosphate doser back online until I got to about 0.10 Phos and 20 nitrate. I've since stopped dosing phosphate and it's holding in the 0.08 range phos an around 15-18 nitrate with the heavier feedings. The colors in most of them have come back and are looking very nice.
I'm stumped, as the pH was incredibly predictable up to this point. I feel like I've run through all the usual suspects in terms of diagnosing the potential issue.
Thoughts? Suggestions?
The system previously ran a base pH of 8.2 and went as high as 8.5 at the end of the light cycle on weekends when no one was in the office. I would say on avg, it topped out in the 8.4 to 8.45 range when the space was occupied with people.
Alk is typically 8.5 dkh.
I dose Kalk at night and I have an ERV unit to cycle the inside and outside air.
C02 in the room ranges from 450 (more or less ambient) to low 600's depending on how many people are in the office.
Here are the changes I've noticed.
pH tops out at around 8.25 during the day now and holds steady there until the lights go off. It peaks at 8.25 around 1pm and then just parks there until the tank goes dark.
I was dosing 4 liters of Kalk at night to maintain a floor of 8.2 and now I'm dosing 8 liters of Kalk at night and it barely gets up to 8.18.
The pH of the Kalk is around 12.5, so I assume it's fully saturated. I always pour more Kalk powder in than necessary when making a batch as insurance. I keep it in a 55g sealed plastic drum.
I was dosing 400ml/day of Alk and Ca to maintain the 8.5dkh and 450ppm Ca parameters, now the tank is only asking for 250ml/day to maintain the same numbers.
To be sure the pH readings were correct, I calibrated my Apex pH probe. Didn't end up needing as it was reading correctly in 7 and 10 solutions, but did it anyway.
I also co-witnessed the Apex's pH readings by using a separate standalone pH meter (Apera).
The tank looks pretty good overall still, but growth has really slowed. A lot. When the tank was consuming 400ml per day and the pH was getting up to the low 8.4's, you could literally see daily growth in a lot of the corals. Albeit small, it was noticeable. But the growth was really was adding up over weeks and months.
The only thing I've changed recently with the routine is I upped the nutrients in the tank. I thought I was running 0.08 Phos and 5-7 nitrates, but the ICP test kept coming back that the phosphates were zero or 0.01ppm. Which explains why some of the acros were looking kind of muted in terms of color.
So I upped the feeding regimen and put the phosphate doser back online until I got to about 0.10 Phos and 20 nitrate. I've since stopped dosing phosphate and it's holding in the 0.08 range phos an around 15-18 nitrate with the heavier feedings. The colors in most of them have come back and are looking very nice.
I'm stumped, as the pH was incredibly predictable up to this point. I feel like I've run through all the usual suspects in terms of diagnosing the potential issue.
Thoughts? Suggestions?
