HELP: Reason For Daily PH Drops?

pwfletcher · 03/19/2018, 09:43 AM

I have a small 30G JBJ rimless with an open top. My PH fluctuates daily from around 8.0 to 7.6. I have noticed that my temperature fluctuates at about the same time, but only by 1 degree (78 to 77). At night, when my main aquarium light is off, my fuse light pops on grow the cheato.

Any thoughts re why my PH would be fluctuating so much and so regularly? Thanks in advance ;-)

pwfletcher · 03/19/2018, 09:44 AM

... forgot to add, I also have an ATO that maintains the water level (and salinity) every hour.

Vinny Kreyling · 03/19/2018, 10:17 AM

PH will increase with light & decrease every night.
Nothing to worry about.

nereefpat · 03/19/2018, 10:20 AM

7.7 - 8.0 seems like a pretty reasonable amount of fluctuation to me.

Even though you are using reverse lighting between display and fuge, you are just seeing the effects of display lighting and photosynthesis causing fluctuating CO2 levels. Same with temp. Your lights are causing temperature fluctuation.

Neither is a problem.

pwfletcher · 03/19/2018, 10:28 AM

Thanks guys!

DarkSkyForever · 03/19/2018, 12:35 PM

To answer your reason for the why your pH swings daily, photosynthesis. CO2 is being pulled out from the water to support photosynthesis, raising your pH. Since you're seeing such variation even with an alternate light cycle on your fuge, one might not be using as much CO2 as the other (more coral than algae for instance).

ca1ore · 03/19/2018, 06:03 PM

While a reverse lit algae refugium (or ATS) can help to mitigate PH cycles, most are simply not big enough to fully offset respiration in the display at night.

Indymann99 · 03/19/2018, 06:27 PM

Totally normal pH swing. Try overlaying your power to lights graph and your pH graph. In my graph below Grey is amps to lights and Orange is pH.

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Kevin Guthrie · 03/19/2018, 10:04 PM

Besides a staggered light regimen the only ways I know to even it out is 1) run your kalk reactor only at lights off. This involves putting your ATO on a timer and getting a variable-output pump tweaked to a low flow rate. 2) running your Ca reactor's CO2 solenoid only during the day. 3) In theory, practice extreme aeration...

03/19/2018, 10:17 AM	#3
Vinny Kreyling Registered Member Join Date: Nov 2002 Location: Miller Place, NY Posts: 7,206	PH will increase with light & decrease every night. Nothing to worry about. __________________ 250 gallon mixed reef, 2 Reefbreeder's Photon V 2, Deepwater BLDC 12, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 6 Tunze pumps.

03/19/2018, 10:20 AM	#4
nereefpat Registered Member Join Date: Apr 2016 Location: Central Nebraska Posts: 3,190	7.7 - 8.0 seems like a pretty reasonable amount of fluctuation to me. Even though you are using reverse lighting between display and fuge, you are just seeing the effects of display lighting and photosynthesis causing fluctuating CO2 levels. Same with temp. Your lights are causing temperature fluctuation. Neither is a problem. __________________ Pat Current Tank Info: 125 in-wall , 40b sump. 6 bulb T5. ASM G2 skimmer. LPS and leathers

03/19/2018, 06:03 PM	#7
ca1ore Grizzled & Cynical Join Date: Apr 2006 Location: Stamford, CT Posts: 17,319	While a reverse lit algae refugium (or ATS) can help to mitigate PH cycles, most are simply not big enough to fully offset respiration in the display at night. __________________ Simon Got back into the hobby ..... planned to keep it simple ..... yeah, right ..... clearly I need a new plan! Pet peeve: anemones host clowns; clowns do not host anemones! Current Tank Info: 450 Reef; 120 refugium; 60 Frag Tank, 30 Introduction tank; multiple QTs

03/19/2018, 06:27 PM	#8
Indymann99 Registered Member Join Date: Apr 2008 Location: Indianapolis Posts: 2,447	Totally normal pH swing. Try overlaying your power to lights graph and your pH graph. In my graph below Grey is amps to lights and Orange is pH. ******** async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"> __________________ 120g DT 100lbs LR / 200 lbs LS, 45g fuge, VectraM1 Return, Herbie drain, 4x RW-8, 2x AI Hydra 26 w AWM, ASM G2, Apex controller, Apex BoB w floats ATO

03/19/2018, 09:44 AM	#2
pwfletcher Registered Member Join Date: Mar 2010 Posts: 50	... forgot to add, I also have an ATO that maintains the water level (and salinity) every hour.

03/19/2018, 10:28 AM	#5
pwfletcher Registered Member Join Date: Mar 2010 Posts: 50	Thanks guys!

03/19/2018, 12:35 PM	#6
DarkSkyForever Registered Member Join Date: Aug 2016 Location: Minneapolis, MN Posts: 92	To answer your reason for the why your pH swings daily, photosynthesis. CO2 is being pulled out from the water to support photosynthesis, raising your pH. Since you're seeing such variation even with an alternate light cycle on your fuge, one might not be using as much CO2 as the other (more coral than algae for instance).

03/19/2018, 10:04 PM	#9
Kevin Guthrie Registered Member Join Date: May 2013 Posts: 506	Besides a staggered light regimen the only ways I know to even it out is 1) run your kalk reactor only at lights off. This involves putting your ATO on a timer and getting a variable-output pump tweaked to a low flow rate. 2) running your Ca reactor's CO2 solenoid only during the day. 3) In theory, practice extreme aeration...