Tank PH issues

[RajM]

My tank is a Nuvo 20 (13g of water) heavily dominated by SPS

Alk : 11dkh ( accidentally raised it beyond and trying to get it back in control slowly. Usually 8dKH)
Cal : 420ppm
Mg : 1400 ppm
No3 : 7-10ppm ( this is from dosing Neo nitrate since reading was 0 ppm few weeks back)
PO4 : 0.1-0.2 ppm (fluctuates based on feeding)

Dosing is All for reef : 23ml
DIY Nopox : 1.5ml

My ph used to swing between 7.8-7.9 over night to 8.2-8.3 day time.
If it ever drifted lower ny Alk was lower than 8 and I used to correct it using BRS alk solution to bring it back.

This has been stable levels for last 4-5 months.

I recently switched to Aquaforest Reef Salt from Red Sea blue bucket because the Red Sea always used to have lower reading requiring correction plus storage issues and parameter stability reading re-correction post waterchange.

The aquaforest has been spot on for cal and mg and alk bit lower than 8 but easy to correct.

However my ph trend has changed. Now I bottom out at 7.5-7.6 with 8.1-8.15 as day highs and today it maxed out at 8.05.

My high KH is from accidentally dosing too much Seachem Balance using apex based on Ph to try and stabilize the overnight ph.

I have left windows open, etc to try to see if it help with co2 but no change.

What could be going on? I suspect something with the salt mix because that’s the only change in system but what could be in the salt to cause this?

I did a 5g waterchange yesterday and my daytime high was 8.2 and night time 7.8 but something changed as day went on.

Should I swap to a different salt, if so what?
What options do I have to correct it.

The corals are still ok and growing.

 

[Fish Fan]

I'd like to follow this to see what the experts say here.

I have also been using AquaForrest salt, I started a couple of years ago using their Sea Salt mix, and I've recently switched to their Reef Salt mix. I too notice it seems to mix a bit lower than advertised for Alk. I am also dosing AFR. Again, I'm interested to see what the replies are here

 

[bubbgee]

Have you lowered your light intensity? That can affect pH.
Was it a fresh mix of nopox diy? Nopox can affect pH.

I use aquaforest hybrid salt and my peak pH is at 8.45 and my low is 7.8 so I am not sure it's the salt, but yes the parameters are lower than I'd like it to be. I use the salt to control my nutrients.

 

[Tangdora]

Just to eliminate the obvious. Should throw your probe into a calibration solution to see if it’s still measuring correctly or if it’s in need of calibration.

 

[RajM]

Have you lowered your light intensity? That can affect pH.
Was it a fresh mix of nopox diy? Nopox can affect pH.

I use aquaforest hybrid salt and my peak pH is at 8.45 and my low is 7.8 so I am not sure it's the salt, but yes the parameters are lower than I'd like it to be. I use the salt to control my nutrients.

I made a gallon of diy NoPox which I am still going thru
It’s not a fresh batch and I will be stopping that since after discussing with Hans Werner over email he said I can add Bacto Balance into AFR so as going to try that.

I don’t mind the drift but I do want the day time ph to be closer to 8.3 if possible.

Just to eliminate the obvious. Should throw your probe into a calibration solution to see if it’s still measuring correctly or if it’s in need of calibration.

I calibrate it every couple months. Last was three weeks ago.. I also have a calibrated Hanna PH pen and I did cross verify it. They both read about +~0.02 points of each other.

 

[rishma]

I’d be surprised if it’s the salt mix. Indoor CO2 and CO2 from carbon dosing is my bet.

I’d suggest doing the outdoor aeration test Randy frequently recommends. Take a cup of tank water, vigorously aerate outdoors for an hour, then test pH. At a dKH 11 I’d suspect your pH could climb above 8.3 in the test cup.

 

[Randy Holmes-Farley]

Salt mix cannot impact pH unless it changed the alkalinity.

pH is determined mathematically by the alkalinity and the CO2 level in the water, the latter of which is usually impacted by the CO2 level in the air.

I’d first recalibrate the pH meter. Organic carbon dosing and AFR both tend to lower pH.

 

[RajM]

Re-calibrated the probe and 2 ph pens (Hanna and BlueLab) and the readings remain same. Today’s peak was only 7.99.

I stopped NoPox dosing today too so the dip I get after the dose is gone.

I added a UV just to test and my PH overnight stayed at 7.8 but as soon as it went off at 8am my ph dipped to 7.65.

Also reduced my AFR dosing yesterday suspecting it’s O2 impact and as expected my Cal and KH trended down so I definitely need the 23ml dose I used to do.

I will do few more water changes with store bought salt water and see if it changes things.
If things don’t change and corals continue to stay happy may be I’ll stop chasing it… …. (Wishful thinking )

 

[Randy Holmes-Farley]

The effect of AFR in pH is pretty small. The effect of NOPOX is larger.

The pH is fine and generally relates quite a bit to CO2 levels in your home air. That may be higher now for some reason, or the previous pH may have been inaccurate.

Photosynthesis being less now is the only possibility that concerns me, if it is caused by a tank problem.

 

[RajM]

The effect of AFR in pH is pretty small. The effect of NOPOX is larger.

The pH is fine and generally relates quite a bit to CO2 levels in your home air. That may be higher now for some reason, or the previous pH may have been inaccurate.

Photosynthesis being less now is the only possibility that concerns me, if it is caused by a tank problem.

So.. I think photosynthesis is definitely playing part a decent part in the issue.

Since my last post, i got another new ph probe. Story remained the same.

I been doing about 600ml of Kalk every night, dosed 50ml every 45 min from 9pm-9am and that helped keep my night ph just above 7.8 to 7.9. So I don’t know if it’s worth it but corals are loving it. So most likely I will continue to do Kalk but I will play around with how much.
Regardless my day time ph only peaked at around 8.12

I also moved my AFR dosing to 1 hour before lights on, because on a local forum it was observed that Bacto balance is causing a dip in PH, which I have mixed into my AFR. Also due to Kalk dosing I have cut my AFT down to 14ml from 23ml. There is a Kalk dose that kicks in sometime after that and that negates the PH dip.

On a the same club forum we were discussing light and I changed mine to mimic that which is heavy on daylight, and to my surprise that day my PH peaked at 8.24. I had tweaked my light before that to push it to 100% but only 3 hours peak which I i think lowered photosynthesis, so going back to 100% for 9 hours might have helped with increase photosynthesis to push my ph higher.
I since then have played out with different settings (since I don’t like daylight colors) I have found that continuous 100% with some white helps peak my ph above 8.2 .. any peaks and valleys configuration to give corals some rest only peaked at 8.15.

So all in all photosynthesis is definitely key driver.

My skimmer pump crapped out trying to pump outside air and probably capsized it. New skimmer is in place but I am not going to risk pumping outside air and these nano skimmer pumps don’t have power to pull air from long distances. Pumping outside air only helps ph by 0.01-0.03 points so it’s ok, I can live without it.

Another observation is swings in ph, the ph swings 0.05 points many times in a day. It used to do that at most 0.01-0.02 but slow, these current fluctuations are fast to drop and slow to regain. And I am not sure she’s going on there.. is it a buffer issue?

I suspect buffer because I had two accidents before these issues creeped up, one time I dosed 70ml of soda ash instead of Calcium chloride. Took me 1 hour to heat and make water for water change, corals were fine but post water change my KH was still 12dKH, subsequent partial water change bought it down to 11dKH which I was ok with. I’ve time I bought it down to 9dKH. But that’s when I had started noticing this issue. Another accident was over dose of sodium hydroxide to bring my ph up and that pushed my KH back about 11.

Is there a chance that the buffer system is messed up?
I still want to target 8.3-8.35 as peak ph at minimum.

 

[UncommonSense]

My skimmer pump crapped out trying to pump outside air and probably capsized it. New skimmer is in place but I am not going to risk pumping outside air and these nano skimmer pumps don’t have power to pull air from long distances. Pumping outside air only helps ph by 0.01-0.03 points so it’s ok, I can live without it.

This is interesting!

What size tubing did you use to plumb a remote skimmer air intake? — the same diameter as the factory skimmer tubing?

 

[RajM]

My skimmer pump crapped out trying to pump outside air and probably capsized it. New skimmer is in place but I am not going to risk pumping outside air and these nano skimmer pumps don’t have power to pull air from long distances. Pumping outside air only helps ph by 0.01-0.03 points so it’s ok, I can live without it.

This is interesting!

What size tubing did you use to plumb a remote skimmer air intake? — the same diameter as the factory skimmer tubing?

When I was using the pump I had a 1/4” tubing to the pump and then from pump to skimmer was also 1/4”. The pump is quite powerful so I had to put an air controller in between, however I increased the flow of air to get more wet skim and I think somewhere along it capsized the pump.
Then I tried without pump but with 1/2” tubing I use for water change. But only until the tank, from the pipe to skimmer was 1/4”. I know that I am most likely losing to air friction but the pump is not that powerful on these nano skimmer to pull air over distances.

 

[eggie]

What time were you dosing the Nopox ?

 

[RajM]

What time were you dosing the Nopox ?

Used to be one hour before lights come on. I am no longer dosing NoPox since I am using Bacto Balance

 

[eggie]

Used to be one hour before lights come on. I am no longer dosing NoPox since I am using Bacto Balance

Try dosing your carbon source in this case Bacto Balance when your lights are in full spectrum so you get less of a PH shift

 

[RajM]

Try dosing your carbon source in this case Bacto Balance when your lights are in full spectrum so you get less of a PH shift

I used to dose NoPox it 4x small doses thru the day but had switched to 1x dose before light hoping that once light turns on it will be steady climb instead of swings.

Now my Bacto is tied go AFR since I have them mixed in same container, in retrospect a bad choice but I’ll see it thru this container for now.

 

[eggie]

I used to dose NoPox it 4x small doses thru the day but had switched to 1x dose before light hoping that once light turns on it will be steady climb instead of swings.

Now my Bacto is tied go AFR since I have them mixed in same container, in retrospect a bad choice but I’ll see it thru this container for now.

you could try alternating your AFR by day when light come on and Kalkwasser by night

 

[FishLvR]

My best reef tank was 7.8-7.9 so I wouldn't stress. You say your corals are loving it so just let it be. I think your tank looks great.

 

[punchy7080]

Bacto balance has a significant impact on pH, just FYI

 

[RajM]

Bacto balance has a significant impact on pH, just FYI

Yes, I have noticed that and so have some of our club members.

My best reef tank was 7.8-7.9 so I wouldn't stress. You say your corals are loving it so just let it be. I think your tank looks great.

Thanks. All the thing you read and that for SPS it’s best to keep PH closer to 8.3 gets you stressed. I used the PH to know if I am using up more Alk because it would only go below 7.8 if my Alk fell below 7.

I am anyways out of options. My last option would be to go to a two part with high PH and traces and let it ride and throw away my PH probe.