pH swings in 20g Nuvo

[reefmaster70]

So I've been out of the reef keeping hobby for almost 25 years, but got back into it this past January, starting up a full mixed reef Nuvo 20g AIO tank in our living room. I am a seasoned reefer, and know how to test, trouble shoot, and make corrections as needed, however this one has me stumped and looking for some advice. I never before had such large pH swings as what this tank gives me (of course I've never had an Apex constantly monitoring pH either) so instead of that pH test twice a week I'd normally do with a static test, I can now observe pH at all times of the day. I have notice that when I am home and have a window or patio door or people in and out my pH stays right around 8.2 from like 1pm until 11pm at night. However over the course of the night when lights are off, etc, my pH will dip down to about 7.78 and stay that way until around 10am the next morning and they'll start to climb again. So I guess I've never paid much attention to this before, and even now, there is no noticeable changes to my tank, all fish, corals, clams, nems all are looking nice and healthy. So what gives? Should I do anything about it? Should I run some 1/4" air line from outside my house into the air intake of my little drop in skimmer in the back? Any thoughts would be most appreciated.

 

[Jason Scalise]

I would say that is normal behavior. It's likely just that you have more data points to observe now (Apex).
I have the same tank (not as if that fact matters too much) but you are seeing the normal diurnal swings from photosynthesis in the water column, algae and corals (if you have them) which is pulling carbonate out of the water when the lights are on which is resulting in raised pH. This reverses when lights are off (ie at night) and the pH drops. You might already know all of this but just in case....

And if before when you tested 2x per week and is was often around the same time of day....you would have had results that were pretty "stable" as those snapshots would likely not have seen the daily ups/downs.

Here is my Apex pH reading over a typical multi-day snapshot. Same kind of swings in magnitude you are describing. No issues at all.



and here is the tank during that timeframe....

 

[reefmaster70]

thank you so much for that informative reply. It helped a ton. Yeah, I am definitely an "old school" reefer, and am used to seeing a "snapshot" of my tank parameters at any given time with testing. These new fangled devices that constantly monitor your tank and send you "Alarms" when numbers are "off" are fine, but. I think they cause more stress than they are worth. LOL .

 

[Tyrone]

I would definitely keep a sharp eye on your PH if you have clams. I have a CO2 scrubber setup with an air pump and air stone on a digital preset time. I have scheduled to come on about 30 minutes after the lights go off. I change out my media about every 2 to 2 and half weeks. I monitor my PH through my Hydros controller.

 

[Bryman]

One option might be converting one of the filter towers in your Nuvo to a refugium and running it in reverse photoperiod with chaeto. I used this method in previous systems for stability and it helped. My Nuvo 20 has only been up for 5 weeks and there's nothing in the display yet besides a shrimp and cleanup crew. I am currently seeing less that 0.2 pH delta per day with my left tower full of chaeto and the IM refugium light attached on the back.

The downside is that it also pulls put nitrate like crazy, so if your nutrients are already low could cause an issue.