Daily pH fluctuations?

[reptilegrrl]

I have seen a few mentions of pH fluctuating throughout the day.  Can someone tell me more about this?  How does your pH change throughout the day?  When is it highest?  When is it lowest? 

[joe09]

the ph is lowest in the am,and highest in the pm.to stablilze your ph you can add baking soda to the pond.it will raise kh,you want it above 80ppm.i keep mine about 140 ppm.you can buy a test kit for this.you want your ph to be stable.it is less stressful on the fish.

[cfarm]

pH is related to how much CO2 is within the system. During the day, photosynthesis is taking place and CO2 is being "fixed" by plant activity, thereby reducing free CO2 which when combined with water is acidic(lower pH). Less free CO2 causes the pH to rise. At night plant respiration, where they actually give off CO2, shifts the free CO2 in the oppositie direction and you have a net buildup which again lowers the  pH reacing a peak, or in this case lowest pH level in the early morning hours. 

The absolute pH number at a given time is not as important as the stability. Quick changes in pH are bad, but slow changes over the course of hours are generally nothing to worry about. As the post above notes, keep your carbonate alkalinity above 80 ppm and you should be fine.

[reptilegrrl]

the ph is lowest in the am,and highest in the pm.to stablilze your ph you can add baking soda to the pond.it will raise kh,you want it above 80ppm.i keep mine about 140 ppm.you can buy a test kit for this.you want your ph to be stable.it is less stressful on the fish.

I don't want to raise my pH, it is already crazily high when it comes out of the tap.  I've been working for weeks to lower it.

[cfarm]

Again, the absolute number is not as important as the rate of change. Unless your tap is 10+ or something, I wouldn't worry about it. Last time I checked mine the pond pH was almost 9.

[reptilegrrl]

Again, the absolute number is not as important as the rate of change. Unless your tap is 10+ or something, I wouldn't worry about it. Last time I checked mine the pond pH was almost 9.

My pond exists because I wanted a good home for my turtle.  High pH is unhealthy for him and caused his shell to retain keratin and then become infected with a fungus.  It took months to get the pH down low enough to stop the fungus from recurring. 

Incidentally, high pH can kill water plants- this happened to my best friend awhile back. 

[cfarm]

Sorry, didn't read your tag line to understand we were talking a devoted turtle pond. But at the pH range of 6.5-9 it wouldn't be an issue for  plants.

What are you using to lower the pH of your tap water and what is your targeted range?

[reptilegrrl]

I am using a commercial pond pH adjuster; I tried peat but it just wasn't acidic enough.

My goal is between 6 and 7; my tap water comes out at 9+.

I checked it the other night and it was back up to 8 after being at 6.5 or so all week before that, so I was wondering if that was just the high end of daily flux, or what... which it apparently is.  I plan to check it in the morning, too, to see where it is at lowest point.