PH Dropping and can't figure out why.

[14 foot reef]

I have been dosing Kalk for over a year now, added a recirculating CO2 scrubber to my Dual Beckett Skimmer. My perimeters are as Follows:

Salinity 1.025- 1.026
Calcium is 450
Alk is avg 9.7 over months and months
Magnesium is avg 1450 over months and months
Temp is 77-78 forever run 2500 watt 220volt commercial heater and 2 ton commercial Chiller
PO4 is .03 - .06 for months
Nitrate is 3 always.

Total running water is 850 gallons with Aqua Ultraviolet 200 watt UV
Lighting is 9 Kessil A360we's with T5 Hybrid fixtures totaling 12' in length.

I Took off line the Vectra L1 pump that was recirculating UV in sump, to direct plumbing the 200 watt UV to my MRC 6100 return pump.
I built plumbing modification 2 days a head of time, ran fresh water through all new plumbing for hours, then plumbed in the big manifold, ( only 2 fittings to glue.) Ran 50 gallons of saltwater through to rinse out the 2 freshly glued fittings, then turned valve to direct water flow to reef.

Over the past few days my PH has been dropping significantly. See Apex Graph in photo.

The only other thing I did was switch from Pharma Kalk to store bought pickling lime because bulk Reefs order has NOT arrived yet.
The Kalk DKH is Testing 22 same as Bulk Pharma Kalk. PH is 12.5 same as Pharma

No changes in population in house, Dogs cats people, nothing.

Any Ideas what could be making my PH drop, could the new plumbing or the 2 glue joints be causing this ?

I have read and watched every possible video from BRS on PH and this truly has me stumped.
I ordered a CO2 meter from Amazon to measure CO2 in my home. That will be here tomorrow, My sump is located in my garage and even tried leaving the garage door open all night and day for 2 straight days.
Any thoughts on this would be greatly appreciated
PH still dropping.

.

 

[Mkkari]

Following

 

[arking_mark]

Without getting to into the details, it looks like your tank flow changed. This change could have raised or lowered your tank aeration. Either could reduce your pH.

If you increased aeration with higher indoor CO2 air (usually the case) through a change in powerheads or in your case return flow and sump dynamics...then that increased aeration will further drive your tank towards equilibrium with the higher CO2 air and decrease your pH.

If your changed reduced your flow and your tank is not aerating well then your tank could be accumulating CO2 and driving down your pH.

You can use a cup aeration test to identify the issue.

On a side note, you usually need an significantly oversized skimmer to overcome your tank aeration from powerheads and returns.

 

[14 foot reef]

Without getting to into the details, it looks like your tank flow changed. This change could have raised or lowered your tank aeration. Either could reduce your pH.

If you increased aeration with higher indoor CO2 air (usually the case) through a change in powerheads or in your case return flow and sump dynamics...then that increased aeration will further drive your tank towards equilibrium with the higher CO2 air and decrease your pH.

If your changed reduced your flow and your tank is not aerating well then your tank could be accumulating CO2 and driving down your pH.

You can use a cup aeration test to identify the issue.

On a side note, you usually need an significantly oversized skimmer to overcome your tank aeration from powerheads and returns.

Tank flow did not change I have flow meters in line on the return, and my overflows are very finicky to change as I am running nearly 6000 gallons per hour from sump to system.

The XF350's are both aimed and moving the exact way they were before and the surface agitation is the same.
The UV is plumbed with 3" PVC input and out put, no lose of pressure or volume is being detected by flow meters.
MP 60's are both running exactly the same.

I really appreciate your idea on this, but if there is even a 1% change in water turn over from before, I would be very surprised.

The uv was plumbed underwater in the sump, so there is not really much surface motion change in the sump either.

When CO2 Meter comes tomorrow, I will be able to measure and log CO2 throughout the day through wifi and data logging.

My Skimmer is very much oversized, its a precision Marine Dual Beckett Skimmer that is an 8" tube 6' tall run by a dedicated Reeflo Hammerhead pump. No changes here, so skimmer can't be undersized or I never would have had readings consistently above 8.25 in the past.

 

[DH78]

My first step would be to verify the calibration of the ph probe.

 

[14 foot reef]

My first step would be to verify the calibration of the ph probe.

Ph is monitored by Piinpoint Marine PH Meter, a Seneye meter ( Data Logging ) and an apex ( Data Logging ). All 3 PH readings are within .01 or.02. So 3 different meters can't all be declining at the exact same rate and amount.

 

[arking_mark]

Tank flow did not change I have flow meters in line on the return, and my overflows are very finicky to change as I am running nearly 6000 gallons per hour from sump to system.

The XF350's are both aimed and moving the exact way they were before and the surface agitation is the same.
The UV is plumbed with 3" PVC input and out put, no lose of pressure or volume is being detected by flow meters.
MP 60's are both running exactly the same.

I really appreciate your idea on this, but if there is even a 1% change in water turn over from before, I would be very surprised.

The uv was plumbed underwater in the sump, so there is not really much surface motion change in the sump either.

When CO2 Meter comes tomorrow, I will be able to measure and log CO2 throughout the day through wifi and data logging.

My Skimmer is very much oversized, its a precision Marine Dual Beckett Skimmer that is an 8" tube 6' tall run by a dedicated Reeflo Hammerhead pump. No changes here, so skimmer can't be undersized or I never would have had readings consistently above 8.25 in the past.

Start with a cup aeration test...

Could be an issue just popped up with CO2 Scrubber or something else...Here are some challenges I found while maintaining stable pH.

Lessons learned in trying to maintain pH stability

For those interested in maintaining pH stability around +/- 0.05 I have a couple of lessons learned. These are things that I found out on my journey to pH stability. Prior to seeking pH stability my tank pH was consistently around ~7.9. However, much of this journey went on before the tank was...

www.reef2reef.com

 

[A;exr54]

I have noticed PH drops in my tank when the home heater is on. Which is not too often because I am in Florida. But it has happened to me because of that.
What I did to combat that is install an airstone in my refugium that pulls air directly from outside. Since then my PH has been very stable.

 

[arking_mark]

How I use a cup aeration test to help pinpoint certain pH issues.

I do 2 tests. One outside and one next to the tank.

I run an airstone for about 1 hour and measure pH.

If the outdoor test isn't around 8.2 NBS, then I know I have a meter or Alk issue...and it's never an Alk issue.

If the next to tank test is below 8.2 NBS, then I have higher indoor CO2...almost always the case.

If the next to tank test is higher than the tank, I have an aeration issue or something else that is driving down pH...it's almost never something else unless I'm dosing something that lowers pH.

If the next to tank test is lower than the tank but not at desired levels, then I need to look at my pH management setup. In my case, this is Kalk dosing, refugium, or CO2/Skimmer.

 

[14 foot reef]

How I use a cup aeration test to help certain pinpoint pH issues.

I do 2 tests. One outside and one next to the tank.

I run an airstone for about 1 hour and measure pH.

If the outdoor test isn't around 8.2 NBS, then I know I have a meter or Alk issue...and it's never an Alk issue.

If the next to tank test is below 8.2 NBS, then I have higher indoor CO2...almost always the case.

If the next to tank test is higher than the tank, I have an aeration issue or something else that is driving down pH...it's almost never something else unless I'm dosing something that lowers pH.

If the next to tank test is lower than the tank but not at desired levels, then I need to look at my pH management setup. In my case, this is Kalk dosing, refugium, or CO2/Skimmer.

This is great and will perform all these test and report back what I find.

 

[14 foot reef]

How I use a cup aeration test to help certain pinpoint pH issues.

I do 2 tests. One outside and one next to the tank.

I run an airstone for about 1 hour and measure pH.

If the outdoor test isn't around 8.2 NBS, then I know I have a meter or Alk issue...and it's never an Alk issue.

If the next to tank test is below 8.2 NBS, then I have higher indoor CO2...almost always the case.

If the next to tank test is higher than the tank, I have an aeration issue or something else that is driving down pH...it's almost never something else unless I'm dosing something that lowers pH.

If the next to tank test is lower than the tank but not at desired levels, then I need to look at my pH management setup. In my case, this is Kalk dosing, refugium, or CO2/Skimmer.

What Kalk are you using, I'm wondering if my switch to pickling lime do to running out of Pharma BRS Kalk might be it.
Have you ever just ran the pickling lime from the grocery store ?

 

[arking_mark]

What Kalk are you using, I'm wondering if my switch to pickling lime do to running out of Pharma BRS Kalk might be it.
Have you ever just ran the pickling lime from the grocery store ?

I use the BRS Kalk.

I've never run pickling lime. However, it's Just food grade vs lab grade and probably just has more impurities. I'd expect it to perform roughly the same at saturation. But It's a change in the set up...so worthy of being suspect.