Low PH question

[Hitman]

So I just rebuilt my canopy on my 240 and in doing so I installed fans that run off the temp in the canopy. When the temp goes above 86 degrees the fans turn on and stay on until the temp goes below 85.5 degrees. The thought was to help cool the 4 - 60” T5’s and 6 AI Sol Blue LED fixtures and to block the light spillover. The light’s stay nice and cool and I no longer have all the light spilling out on my floor so problems solved right. Wrong!!! Per my apex 15 minutes after all my lights go out and the fans stop running my PH takes a dive from 8.3 to 8.15 then a slow and steady drop throughout the night to 7.99. Before fully inclosing my canopy my PH stayed between 8.2 & 8.3.

So to the point of my post.

Did sealing up the canopy cause this nightly extreme drop in PH by only having airflow while the fans are on when the temp is above 86 degrees?

Per apex my tank temp never falls below 78.5 or goes above 78.7 when the fans are off so my heaters never turn on over night as the on temp is set at 78.4

Do I try to run the fans 24/7 and see if my PH goes back up?
Am I over thinking this?

 

[Peach02]

So I just rebuilt my canopy on my 240 and in doing so I installed fans that run off the temp in the canopy. When the temp goes above 86 degrees the fans turn on and stay on until the temp goes below 85.5 degrees. The thought was to help cool the 4 - 60” T5’s and 6 AI Sol Blue LED fixtures and to block the light spillover. The light’s stay nice and cool and I no longer have all the light spilling out on my floor so problems solved right. Wrong!!! Per my apex 15 minutes after all my lights go out and the fans stop running my PH takes a dive from 8.3 to 8.15 then a slow and steady drop throughout the night to 7.99. Before fully inclosing my canopy my PH stayed between 8.2 & 8.3.

So to the point of my post.

Did sealing up the canopy cause this nightly extreme drop in PH by only having airflow while the fans are on when the temp is above 86 degrees?

Per apex my tank temp never falls below 78.5 or goes above 78.7 when the fans are off so my heaters never turn on over night as the on temp is set at 78.4

Do I try to run the fans 24/7 and see if my PH goes back up?
Am I over thinking this?

the ideal pH range is between 8.1-8.4 so it should be okay at day time. Night time is odd because I wouldn’t think light effects pH however it’s a trend your noticing.
I wouldn’t worry about it too much unless your fish / coral start to show signs of ill health. But a pH of 7.99-8.3 are both barely alkaline so in my understanding it should be okay

 

[Dr. Dendrostein]

the ideal pH range is between 8.1-8.4 so it should be okay at day time. Night time is odd because I wouldn’t think light effects pH however it’s a trend your noticing.
I wouldn’t worry about it too much unless your fish / coral start to show signs of ill health. But a pH of 7.99-8.3 are both barely alkaline so in my understanding it should be okay

I buy real ocean H2O and pH is 8.0, your fine

 

[ckalupa]

PH dropping after lights out is normal as photosynthesis stops and CO2 is not being processed out. It’s why some people dose their alkalinity at night and other run their refuge lights at night to maintain photosynthesis in the macro to keep ph stable. Swings down after lights go out are normal.

And yes- sealing the top may very well have slowed exchange of gas at night as the in-tank photosynthetic life stops using up the CO2 and gas exchange at the surface is less now. Try running the fans at night. Did you not see the swing down prior to the canopy?

 

[Dr. Reef]

This is normal for pH to drop after lights go off. To counter that hobbyists use opposite light schedule and run some cheato or other macro algae in sump and turn sump lights on which helps stable pH a bit better than sudden drop.
Enclosing the tank can prevent air exchange which could lead to CO2 buildup that can in turn effect pH. I would let the fans run through the night after main lights go out or at least for few hours after.

 

[Hitman]

PH dropping after lights out is normal as photosynthesis stops and CO2 is not being processed out. It’s why some people dose their alkalinity at night and other run their refuge lights at night to maintain photosynthesis in the macro to keep ph stable. Swings down after lights go out are normal.

And yes- sealing the top may very well have slowed exchange of gas at night as the in-tank photosynthetic life stops using up the CO2 and gas exchange at the surface is less now. Try running the fans at night. Did you not see the swing down prior to the canopy?

My Kessil H380 runs over my Cheato which turns on 2 hours before lights out and off 2 hours after lights turn back on. So I have the opposite lighting. Before I sealed the canopy up my PH only dropped to 8.2 at night normally and looking at my logs 8.16 was the lowest at night starting from the day the apex was installed.
I ran the fans on low all night and my PH only fell to 8.1 so thats definitely a improvement. I guess my lesson learned this week was a tight sealed canopy is not a good idea as the wife was none to happy hearing the fans all night lol. Time to find some quiet computer fans or put the canopy back the way it was and deal with the light spill over.

 

[ckalupa]

A lot of people experience a to drop into the high 7’s overnight. Good that you figured out the canopy. As it was the major change it would be the first place to look. Thanks for sharing the experience.

 

[Hitman]

Well I will not know until tonight but I may have won the dumb dumb award!!! I pulled everything apart to put the canopy back the way it was and the wife ( mind you never has a hand in a tank maintenance) goes hey why is this barrel have a small hose coming out one side and back in the other? So I look to see what she is talking about and I I see I never put the Kalk dosing tube back in the tank when I moved the barrel out of the way! So the doser was showing it was dosing on schedule but it was going right back into the barrel:mad: Well I guess I can put it in writing she may have saved the day or at least my nerves! Lol

 

[Randy Holmes-Farley]

I buy real ocean H2O and pH is 8.0, your fine

Not sure that means anything. Actual ocean water would have pH too low if CO2 were high. Your pH does not reflect the pH in the actual ocean.

 

[Randy Holmes-Farley]

So I just rebuilt my canopy on my 240 and in doing so I installed fans that run off the temp in the canopy. When the temp goes above 86 degrees the fans turn on and stay on until the temp goes below 85.5 degrees. The thought was to help cool the 4 - 60” T5’s and 6 AI Sol Blue LED fixtures and to block the light spillover. The light’s stay nice and cool and I no longer have all the light spilling out on my floor so problems solved right. Wrong!!! Per my apex 15 minutes after all my lights go out and the fans stop running my PH takes a dive from 8.3 to 8.15 then a slow and steady drop throughout the night to 7.99. Before fully inclosing my canopy my PH stayed between 8.2 & 8.3.

So to the point of my post.

Did sealing up the canopy cause this nightly extreme drop in PH by only having airflow while the fans are on when the temp is above 86 degrees?

Per apex my tank temp never falls below 78.5 or goes above 78.7 when the fans are off so my heaters never turn on over night as the on temp is set at 78.4

Do I try to run the fans 24/7 and see if my PH goes back up?
Am I over thinking this?

I think the canopy sealing is a likely explanation. I would not excessively worry unless the pH drops below 7.8.

 

[Hitman]

I think the canopy sealing is a likely explanation. I would not excessively worry unless the pH drops below 7.8.

Thank you @Randy Holmes-Farley

 

[Dr. Dendrostein]

Not sure that means anything. Actual ocean water would have pH too low if CO2 were high. Your pH does not reflect the pH in the actual ocean.

From Ocean Acidification
"Over the past 300 million years, ocean pH has been slightly basic, averaging about 8.2. Today, it is around 8.1,"
I'm off by .1, I probably need to calibration ph sense.