PH Swings - should I care?

[Jeremy Luke]

I recently purchased a controller (Profilux 4). Prior to this purchase I'll admit that I wasn't testing PH on my tank. Now that I have my controller monitoring it I have been paying attention. It seems that my PH was bottoming at about 8 and hitting just shy of 8.3 prior to lights out.

I noticed last night about mid light cycle the PH was only at 8.07 and thought that was strange. I just looked at my dashboard and my PH is only at 7.77. I thought about it and I realize the cause for the lowered PH. My tank is in the basement. During the summer I have custody of my daughters every other week. My daughters' bedrooms are in the basement. Last week, when the PH was up in the "good" range, my daughters were not at my house. Now that they are back my PH is perhaps low.

My question is, would you care? 50% of the time my PH will fluctuate between 8.0-8.3 and 50% of the time my PH will fluctuate between 7.7-8.1. I suppose I could run a CO2 scrubber when they are there if I had to. Do you think it will matter that much?

 

[garethwood]

thats not a huge swing personally i wouldnt worry. if you hadnt started monitoring it then you wouldnt if known about it so if your tanks fine then dont mess about i say.. chasing numbers, unnecessary equipment all more to pay for and go wrong. : )
do you have a reverse lit fuge? this always help keep a stable.. maybe rather than mesing with the tank you could just get an ozonator for the basement to stick on when they come over?

 

[clsanchez77]

Nah, you are pretty near perfect. People are way over stressing over pH. The 'acceptable' range is 7.8 to 8.5 (Source: Reef Aquarium Water Parameters by Randy Holmes-Farley), but you should never swing that much in a day. A daily +/- 0.3 is pretty healthy. And know that over time the pH will drift up and down so don't sweat that either. If you were outside this range, you would want to take corrective action, such as aeration with fresh air, changing your alkalinity dosing methods, etc.

If you are chronically low, using a CO2 scurbber is an option but at a cost. I would use kalkwasser to supplement your alkalinity and calcium first as the kalkwasser will react with dissolved CO2 to produce the alkalinity component. Here is a video on a CO2 scrubber to see what is involved: http://www.bulkreefsupply.com/video/view/faq-40-outside-air-or-co2-scrubbers/

I would never go as far as to inject CO2 into a tank to reduce pH, I would probably change the kalkwasser reactor for a calcium reactor if that remained chronic.

 

[clsanchez77]

Also keep in mind that many electronic controls are subject to a lot of interference on pH, ORP and conductivity measurements. So dont put all your stock in the controllers pH log. If the pH is so far off that it is of a concern, then first, check the probe wire to make sure it is not parallel to any 120vac lines, coiled up or in a configuration that can lead to interference. Secondly, calibrate and verify calibration on the probe. Then use another method to verify the pH. Once a week, I still test pH with a test kit when I am testing my alkalinity just to make sure the probe is still on par. The pH test kit comes free with the alkalinity kit anyways

 

[Jeremy Luke]

Thanks for the input folks. I'll leave it be for now.

For the immediate I'll just watch to see if my Alk uptake rate stays steady for when the PH range is lower.

 

[clsanchez77]

Thanks for the input folks. I'll leave it be for now.

For the immediate I'll just watch to see if my Alk uptake rate stays steady for when the PH range is lower.

I would expect it to decrease as calcification should be slower...but then corals have the ability to locally manipulate the pH to support calcification, so maybe it won't.