Ph - When to actually be concerned?

[jd-woodlands]

I know there are lots of threads about not chasing Ph in our tanks, but when is there actual cause for concern?

My SPS tank PH cycle looks like this: 7.6 - 8.25. The probe is calibrated and accurate, checked against a freshly calibrated hanna ph checker.

This is also with a C02 scrubber that the skimmer is pulling through.. however its not a large skimmer and this is not a large tank at < 30 gallons.

Should I start taking corrective action or just leave this alone? I feel like this swing is a little higher than normal from reading other posts.

 

[Brew12]

I know there are lots of threads about not chasing Ph in our tanks, but when is there actual cause for concern?

My SPS tank PH cycle looks like this: 7.6 - 8.25. The probe is calibrated and accurate, checked against a freshly calibrated hanna ph checker.

This is also with a C02 scrubber that the skimmer is pulling through.. however its not a large skimmer and this is not a large tank at < 30 gallons.

Should I start taking corrective action or just leave this alone? I feel like this swing is a little higher than normal from reading other posts.

That swing is very high. I'm guessing with the size of the tank that you don't run a refugium?

 

[jd-woodlands]

That swing is very high. I'm guessing with the size of the tank that you don't run a refugium?

There is a very small one in the back ( This is an AIO) I run a IM MagnaFuge light during the night and grow a tennis ball size amount of chaeto. So I am doing that, plus C02 scrubbing and still have this swing.

 

[Brew12]

There is a very small one in the back ( This is an AIO) I run a IM MagnaFuge light during the night and grow a tennis ball size amount of chaeto. So I am doing that, plus C02 scrubbing and still have this swing.

That is pretty crazy. Are you sure your CO2 media isn't exhausted? Did you add a little water to the media to keep it working longer?

 

[jd-woodlands]

Fresh C02 media, water in the base of the container plus the intake goes to a mason jar with water in it for a bit more humidity.

 

[Brew12]

How are you maintaining alkalinity? If your CO2 is reasonably stable, and it seems like it should be, than alkalinity is the other factor that can impact pH. It seems counter intuitive for alkalinity to drop at night unless you do most of your alk dosing during the day and not spread out.

 

[jd-woodlands]

How are you maintaining alkalinity? If your CO2 is reasonably stable, and it seems like it should be, than alkalinity is the other factor that can impact pH. It seems counter intuitive for alkalinity to drop at night unless you do most of your alk dosing during the day and not spread out.

Alk is dosed hourly throughout the day and there is dosing during the night as well. It stays fairly constant. I dose 1 ml every hour and 2 mls an hour during mid-day. At night it moves to every other hour of 1 ml. This keeps me around 8.5 - 9.0. Calcium is dosed hourly as well, and mag is kept at elevated levels.

 

[Brew12]

Alk is dosed hourly throughout the day and there is dosing during the night as well. It stays fairly constant. I dose 1 ml every hour and 2 mls an hour during mid-day. At night it moves to every other hour of 1 ml. This keeps me around 8.5 - 9.0. Calcium is dosed hourly as well, and mag is kept at elevated levels.

I would be very curious to see where your alkalinity is at around midnight as opposed to noon. I have a feeling you are getting such a huge spike for 3 reasons. Lower alkalinity at night. Fuge consuming much less CO2 than the DT when lit, and not enough air exchange from the skimmer to counter the impact of oxygen consumption in the DT. But... as I think about this more... I think it would take a crazy alk swing to cause this much change in pH so I doubt the alk thing is overly critical.

I'd imagine if things weren't growing well in your tank you wouldn't see this big of a swing so I'm not sure I would do much about it.

If you really want to try something, the only thing that immediately comes to mind is to not run the CO2 scrubber on the skimmer but run it on an air stone, only at night, between the skimmer and the return pump. I've never had an AIO so not sure if that is practical.

Maybe someone else has a better idea.

 

[Thor2j]

If you want to level it out only dose the alk after lights go out and dose calc during the day. That's what I do and keeps my ph swing around .2 and my dkh doesnt very by more then .2 as well.

 

[jd-woodlands]

I would be very curious to see where your alkalinity is at around midnight as opposed to noon. I have a feeling you are getting such a huge spike for 3 reasons. Lower alkalinity at night. Fuge consuming much less CO2 than the DT when lit, and not enough air exchange from the skimmer to counter the impact of oxygen consumption in the DT. But... as I think about this more... I think it would take a crazy alk swing to cause this much change in pH so I doubt the alk thing is overly critical.

I'd imagine if things weren't growing well in your tank you wouldn't see this big of a swing so I'm not sure I would do much about it.

If you really want to try something, the only thing that immediately comes to mind is to not run the CO2 scrubber on the skimmer but run it on an air stone, only at night, between the skimmer and the return pump. I've never had an AIO so not sure if that is practical.

Maybe someone else has a better idea.

Actually tried the airstone using "micro / nano bubble scrubbing" and it didn't make any measurable impact during the night.

If i didn't dose ALK during my 12 hour day I would be swinging down 1.25 dkh... i dose about 30ML a day at my current consumption rate. I think that would be even worse for stability.

not sure what to do about it, if anything. Just seems to be a very large daily swing.