Tried all I can to fix pH

rob safron · Jul 27, 2017

So I am having trouble with Ph in my 125 gallon mixed reef. Up to now I dosed via pumps C-Balance and have a hang-on skimmer connected to CO2 scrubber. I have 2 HOB Refugiums with Cheato. I also dose vinegar 28 mls/day. My measured phosphate via Hanna is 0 and nitrate 0. I also tried placing airline outside with no change. Last 2 day I am dosing Kalk in my ATO water mixed at 2 tsp per gallon. Probably add about 1 gallon per day and dosing midnight to 9 am every hour. You can see my ph probe graph below and I do have 2 probes that agree. On the 3rd day shown I dosed washing soda hoping that raising ph that would be help keep it high. You can also see 2 spikes the last couple morning that I added a larger dose of kalk water but is short lived and drops back down. This morning I'm down to 7.6. Not sure what else to do.

creas · Jul 27, 2017

There are people who know more than me that will chime in. I would ease back on the vinegar. Zero is too low for No3 and Po4 (I assume you're dosing vinegar to keep these low?) and vinegar will lower pH. I don't know if suddenly stopping vinegar is bad or not but I would stop and watch my levels. Do you have a lot of corals/coralline in your tank?

Randy Holmes-Farley · Jul 27, 2017

You can't bring in fresher air via open windows?

rob safron · Jul 27, 2017

Yes carbon dose for nutrient reduction. I do have many soft, LPS and a few SPS corals and great coralline growth. It's 90+ lately in St Louis so window would be hard. Did try running the line out a window. Didn't seem to help. This is a fairly new issue, last month or so. Should I not worry about hitting 7.6 for now? Maybe a summer issue.

Randy Holmes-Farley · Jul 27, 2017

I'd personally not be happy at pH 7.6, but if you run out of easy options and do not have apparent tank issues with hard corals, I wouldn't agonize over it.

Limewater (kalkwasser) dosed every night is an option.

rob safron · Jul 27, 2017

Yes I have been nightly dosing Kalk every hour from 0000 till 0900 for 3 nights now. My mix is 2 tsp per gallon water and probably evaporate around 1/2 to 1 gallon a day. Does not seem to make a difference unless I bolus a larger amount at once but the increase is short lived.

amps · Jul 27, 2017

What's your alkalinity. cal and mag at? Your alk can affect your PH easily.

rob safron · Jul 27, 2017

Yes. CA 425 mg 1430 and Alk 8.0. Keeping Alk low for low nutrient. May not be an ultra low nutrient tank but didn't want to chance burnt tips.

Randy Holmes-Farley · Jul 27, 2017

rob safron said:
Yes I have been nightly dosing Kalk every hour from 0000 till 0900 for 3 nights now. My mix is 2 tsp per gallon water and probably evaporate around 1/2 to 1 gallon a day. Does not seem to make a difference unless I bolus a larger amount at once but the increase is short lived.

Limewater soaks up some of the excess CO2 that is causing the low pH, but continued aeration always brings in more.

rob safron · Jul 27, 2017

Maybe add some bubblers with the pump located outside the window. Worth a try. Thanks for input. Hoping for an easy answer but never is.

Randy Holmes-Farley · Jul 27, 2017

Do you sleep in the room with the tank? The big swing suggests the tank is not that well aerated (complete aeration with unchanging air will show no pH swing day to night).

rob safron · Jul 27, 2017

It is located in our walkout basement with windows. There is 1 bedroom down there but not a very busy space overall. This year I have put some money in an apex and always tested PH with the various kits. They all still show 8.0-8.2 but I trust my two probes over that. I guess it has to be summer and just didn't notice prior to Apex probes. Someone wrote to stop surface agitation as that can also add co2 in room back into the water verses adding O2 in. Any truth there? I have 3 Neptune pumps running pulse my skimmer and 2 HOB refugiums. Flow does not appear to be an issue.

Randy Holmes-Farley · Jul 27, 2017

pH is independent of O2.

Aeration will drive the CO2 in the the water to be in equilibrium with the air. That can add or remove CO2. It will reduce the day to night difference, but whether that is by lowering the day peak or raising the night minimum I can't say.

Some folks have issues with Apex pH for reasons I do not understand. Maybe it is higher than you think.

rob safron · Jul 27, 2017

Huh. It does read spot on when I thew it in cal solution. But I have 3 pH kits and they all show above 8.0

Randy Holmes-Farley · Jul 27, 2017

Might try a new set of calibration fluids.

rob safron · Jul 27, 2017

Thanks for the feedback.

Amboss72 · Jul 27, 2017

I've found living in Park City, Utah at an elevation of 7000ft seems to make it a but more challenging keeping my ph up. Less oxygen up here!

Randy Holmes-Farley · Jul 27, 2017

Amboss72 said:
I've found living in Park City, Utah at an elevation of 7000ft seems to make it a but more challenging keeping my ph up. Less oxygen up here!

I actually think the effect is the opposite. A lower ambient level of CO2 will promote higher pH.

Maybe the house is tighter due to the climate, holding in CO2 better.

Amboss72 · Jul 28, 2017

Randy Holmes-Farley said:
I actually think the effect is the opposite. A lower ambient level of CO2 will promote higher pH.

Maybe the house is tighter due to the climate, holding in CO2 better.

I wrote without thinking more deeply about what I wrote. I do know this, I'm old school and have copies of the various articles you've published Randy Holmes-Farley. Thank you for your efforts in writing them. You're able to take challenging topics(for me) like chemical reactions and explain them simply. In my book that's a quality of someone who truly understands the topic they've mastered. Thank you!

Forsaken77 · Jul 28, 2017

rob safron said:
Yes. CA 425 mg 1430 and Alk 8.0. Keeping Alk low for low nutrient. May not be an ultra low nutrient tank but didn't want to chance burnt tips.

I have been using AquaVitro Balance to raise Ph. It doesn't affect Alk at all and works great for when the air conditioning is on for days straight. Running an air hose outside isn't enough. After a week of closed windows and doors, I had a Ph of 7.8. It took hours for the Ph to rise to 8.1 with every window and door open. My 93 cube is also right next to my screen door and it still took that long.

Check out Balance.