Ph swings upto 8.6 everyday religiously, why?

[Rijodan]

Everyday my ph is going from 8.0 to 8.6. Same time and peak everyday. The low is always 6am an hour afyer i leave and peaks around 6 when gf gets home. Lights turn on around 8am and turn off around 9. No idea.

 

[Rijodan]

Herss my chart

 

[Dennis Cartier]

Have you calibrated your pH probe recently? The swing is expected, but 8.6 is higher than average.

Your tank's pH is directly related to the CO2 content of the water and surrounding air. If your home is air tight and has little exchange, your respiration along with your girlfriend's will raise the CO2 content and cause the pH in the tank to fall. After you both leave for work, and the lights turn on, the demand for CO2 will increase in the tank, causing the pH to rise. Bolstered by the falling CO2 level within your home as your not there breathing.

Do you notice the same swing on the weekend's (assuming someone stays home)?

 

[Dennis Cartier]

The other possibility is the aeration in your tank is lacking. If your tank is not able to equalize with the surrounding air, than the lighted period can drive the pH quite high, followed by a steep decline at night when the animals respiration will push the pH down. Do you have a glass lid on the tank to try to limit evaporation by chance?

 

[Rijodan]

i calibrated the apex when i got it back around 26ish of april, so should be good, possible the calibration fluid was old but unknown at this time and i have double checked at times with my hanna ph cheker and it is usually with .01-.02 of that the apex is currently reading.

The aeration is exactly the the same within 0.05 of weekends vs weekdays. typically no one other than dog and cat at home mon-fri 730-430, but sat and sunday us and kiddo are all home most of day

i run a reefocto 200-int full blow as well as my return pumps both are moving top flow water and have a gyre that moves the top of water, a carbon doser that has freefall water an inch, my return freefalls water about an inch into a sock, the return of the protein skimmer free falls. The room is only used when i'm in there or someone is watching tank, otherwise its just a room that's open to rest of house. LEaving the window to the room does not seem to make a difference in pH

this is a 40"long 110g tank so maybe its not enough surface area? just trying to get away from this 8.6 as i know the swing will happen, just dont want it swinging like the unashamed old man in the locker room.

no glass lid just the 2.5in rim to help brace it. evap im prob doing somewhere between 8-10gal a week at worst

 

[vetteguy53081]

Calibrate again and also check with PH test kit.
It is normal for ph to drop at night and rise with lights on but as you know, 8.6 is not a norm. Also check Alk which affects PH

 

[ZombieEngineer]

pH probes drift a fair bit over time. Drifting 0.05ish per month is pretty typical.

The variation between day and night will be accurate, but good chance your high pH is actually closer to 8.5

You can minimize this change by running your refugium light opposite your display lights.

 

[Dennis Cartier]

i calibrated the apex when i got it back around 26ish of april, so should be good, possible the calibration fluid was old but unknown at this time and i have double checked at times with my hanna ph cheker and it is usually with .01-.02 of that the apex is currently reading.

The aeration is exactly the the same within 0.05 of weekends vs weekdays. typically no one other than dog and cat at home mon-fri 730-430, but sat and sunday us and kiddo are all home most of day

i run a reefocto 200-int full blow as well as my return pumps both are moving top flow water and have a gyre that moves the top of water, a carbon doser that has freefall water an inch, my return freefalls water about an inch into a sock, the return of the protein skimmer free falls. The room is only used when i'm in there or someone is watching tank, otherwise its just a room that's open to rest of house. Leaving the window to the room does not seem to make a difference in pH

this is a 40"long 110g tank so maybe its not enough surface area? just trying to get away from this 8.6 as i know the swing will happen, just dont want it swinging like the unashamed old man in the locker room.

no glass lid just the 2.5in rim to help brace it. evap im prob doing somewhere between 8-10gal a week at worst

Ok, so if opening a window does not affect the pH, than your probe is suspect. It sounds like you have ample aeration in the tank, and by your mention of a Carbon Doser, a CaRx as well? Which tends to depress pH, the opposite of what you are seeing. So another calibration is in order and perhaps a manual test kit as another suggested.

 

[Rijodan]

Ok, so if opening a window does not affect the pH, than your probe is suspect. It sounds like you have ample aeration in the tank, and by your mention of a Carbon Doser, a CaRx as well? Which tends to depress pH, the opposite of what you are seeing. So another calibration is in order and perhaps a manual test kit as another suggested.

My bad, carbon reactor! Other than ab+ no dosing on this tank, and even that is hand dosed. whether i leave window open or leave closed makes no meaningful difference in ph. like i said room is empty most times, and large vaulted ceilings and one of those that always has to have fans moving everything so with only 3 people in the house i doubt CO2 is much of a factor, atleast to this degree.

i know i had low alk last night let me run go check again. I got to where most things in tank were happy so i haven't watched it as I should have been, with me wanting to get into so higher end stuff I want to make sure stuff is hnot detrimental hence me wanting this swing under control.

 

[Rijodan]

pH probes drift a fair bit over time. Drifting 0.05ish per month is pretty typical.

The variation between day and night will be accurate, but good chance your high pH is actually closer to 8.5

You can minimize this change by running your refugium light opposite your display lights.

If the hanna wasnt within 0,01 id say it could be off but with both being so close id trust my gut that this is similar. otherwise im still having a .6 swing just now from maybe 7.9-8.5

also no refugium on this tank. messy things they are.

 

[Rijodan]

so around 8 last night i was at 6.8 dkh and today im at 6.4dkh at 5

 

[ZombieEngineer]

so around 8 last night i was at 6.8 dkh and today im at 6.4dkh at 5

Check the pH of your RODI water. Something is not adding up if you have high pH but have low ALK and don't dose high pH additives regularly like sodium carbonate or a form of hydroxide.

@Randy Holmes-Farley might have some other ideas, but something is not lining up here.

 

[Rijodan]

So maybe i need to calibrate my probes as they both read 9ish when first dipped in ato and after a few min of soaking the hanna dropped to 6.9 and the apex to 6.4

 

[Rijodan]

Note the ato is just rodi in a slimjim

 

[Randy Holmes-Farley Verified Community Expert]

The water is not well aerated since the swing is so high. When the pH is at the high end, try aerating a cup of tank water for an hour and remeasure the pH.

 

[Rijodan]

The water is not well aerated since the swing is so high. When the pH is at the high end, try aerating a cup of tank water for an hour and remeasure the pH.

so this response peaked an idea, as the swing doesn't change with people but does coincide with when house temp changes, as i run 78 during day and cool during sleep. What if my probes arent miscalibrated and my ato water really is 9? then as its topped off as evap its essentially dosing high pH water into the tank?

I had to order some calibration fluid for the apex and hanna checker as the stuff i did have was expired so waiting till friday for that but until then i chunked an airstone into the ato and see what happens still tests at roughly 9 when first check and fresh ro from machine at 6.5 and still within a hairsbreath of the apex probe.

On the other hand watching this ph everyday ive also been checking with my alk and seems im going through .4-.3 a day as sun it was 6.8 yesterday 6.4 and today 6.1 so 5g water change to try and get it up and then once ive found where my pH really lies i guess i need to do some soda ash or bicarbonate dosing to help keep that up .

 

[Rijodan]

so after an hour or so of the air stone the ato is now testing at 6.9 so well see how it goes the next couple days while im waiting for calibration fluid to come it

 

[Rijodan]

So seems that idea is a bust. While the ato is testing a better 6.9 than the 9 it was, it had no affect what-so-ever on tank ph, so took the airstone out and put in sump. See tomorrow if that helps any.

After 5g change yesterday and another 24hrs alk was at 6.3 so did another 5g today. Fighting nitrates so no harm with a couple extra w/c to boost that alk.

 

[Randy Holmes-Farley Verified Community Expert]

If you are talking about measuring the pH of RO/DI, don’t bother. Our meters cannot correctly read the pH and it is. Ever a cause of high or low pH if it is 0 ppm TDS when produced.

 

[Rijodan]

If you are talking about measuring the pH of RO/DI, don’t bother. Our meters cannot correctly read the pH and it is. Ever a cause of high or low pH if it is 0 ppm TDS when produced.

Yeah i found another comment of yours from a few years ago that basically stated that. Made me feel a lil dumb cause thats the whole point of rodi that it is basically pure water so there shouldnt be any extra H ions. What little CO2 that would be absorbed and added as top of would be minisxule to the size of tank.

Just filling time until my calibration fluids get here. Until im 100% of what the readings are, dont want to get too far into tryna fix it as i might be throwing it all out of whack even further.