PH Swings

[ReefAddict]

Are PH swings like this normal?

 

My refugium light comes on shortly after the DT lights turn off.  I get a pretty significant PH swing (at least according to my Apex).  It seems to happen when the fuge lights come on and also when they turn off.

 

 

[miggs76]

That's a pretty big swing....most mine swings is .2. Do you dose?

[ReefAddict]

I dose BRS 2 part, I dose Soda Ash at midnight, and Calcium around 2:00pm.  The swing starts at around 8:30pm my fuge light comes on at 8:00pm then again in the morning when the light goes out at 8:00 am.

 

my DKH is currently 8.4 using the Hanna Checker.

[Origami]

I dose BRS 2 part, I dose Soda Ash at midnight, and Calcium around 2:00pm.  The swing starts at around 8:30pm my fuge light comes on at 8:00pm then again in the morning when the light goes out at 8:00 am.

 

my DKH is currently 8.4 using the Hanna Checker.

Check your logic and the timing on the expanded graph view. Make sure that it's actually coming at the time when the lights go on and off. That swing is really large (and fast) for just lighting. When was the last time the pH probe was calibrated?  

 

When the lights go on, you'd expect photosynthesis to start. That process consumes CO2 and produces oxygen. The result is lower dissolved CO2 in the water and, therefore, higher pH. The swing toward a higher pH should be gradual and cumulative.

 

Similarly, when the lights go out, photosynthesis stops and corals/plants begin to respire (that is, they breath in oxygen and release CO2). Along with the other animals in your tank, this causes dissolved CO2 to accumulate, making the water more acidic. Result? The pH goes lower at night.

 

Now, when you dose soda ash at night, CO2 is taken up, bringing pH up (however, if there's enough respiration going on, you may not see a big swing). 

 

So something's not quite what I would expect in your picture. My diurnal pH swing is more like 0.2 points and is more sinusoidal - not shaped like a square wave (like what you have).

[Origami]

Another thing, ORP normally mirrors (in reverse) pH in its basic shape. I don't see that in your screenshot.

[sethsolomon]

Check your logic and the timing on the expanded graph view. Make sure that it's actually coming at the time when the lights go on and off. That swing is really large (and fast) for just lighting. When was the last time the pH probe was calibrated?  

 

+1 calibrate your ph probe.  And check the timers on the dosers. those are not normal spikes in ph.

 

 

 Also, instead of turning on your fuge after the lights turn off, turn it on about 20 min before your tank lights shut off.  This will help lessen the drop at nighttime.

[ReefAddict]

My PH probe was calibrated a few months ago, my Apex is only a 3-4 months old.   Do they need to be calibrated frequently? 

 

I'll check the timer on my doser, it's a GHL doser 2 when I have been near the tank I do hear it at the appropriate times. 

[Origami]

When things look unusual or before you make drastic changes, it's always good to check calibration to make sure that the "truth" that you're seeing (and getting ready to make decisions on) is really true.

 

Get a screen shot of your pH probe measurement for the last 7 days and the last 24 hours.

 

I'm curious and would like to look at how the Apex outlets are programmed and compare it to the pH probe activity. Can you dump the program summary to a text file and post it here? It would be interesting to see what might correlate with the times of your pH swings. To get the program summary, go to Apex Fusion and select your controller. Then, in the upper left (where you see your apex's name, select "Summary" from the drop down menu. Copy everything from "Configuration Summary" on down and paste it as text into your post. It'll look ugly, but we can sort it out afterwards. 

[madweazl]

Sometimes the weather sucks and there isn't much you can do about it. 

 

[joro]

My swing is usually no more than +/- 0.2 and I also use an opposite lighting schedule where the fuge light comes on around the time the main tank lights go solely to blue/nighttime mode. 

[gmerek2]

 

My ph probe needs calibrated but here is what my tank does

Sent from my iPhone using Tapatalk

Edited July 2, 2017 by gmerek2

[ReefAddict]

So far it looks like cleaning has done the trick.  I cleaned it yesterday while doing normal maintenance and it has been steady ever since.  Thanks for all the advice.