pH questions

[BriDroid]

My tank runs about 7.8pH. When I mix up my water, TM Pro Reef, it comes out to about 8.2pH. I did a small water change yesterday, just to have a gallon of old aquarium water to dip some new corals in today.

When I add the new saltwater, the tank comes up to around 8.0pH for a short while, then drops back to 7.8pH.

The old water is in a bucket on the floor in the same room, with a lid sitting over the top, not sealed tight. I checked the pH this morning on that bucket of old water, only thing running is a heater set to 78 and a small powerhead. The pH in the bucket of old saltwater is 8.2pH and the tank is 7.8pH.

Why is it dropping in my tank, but raising back up when sitting on the floor? I'm trying to wrap my head around this one?

 

[William Chiavetta]

Are your tests off maybe? only thing I can think of

 

[twentyleagues]

There is little to no biological processes in the bucket. Fish breath and create co2, biological processes consume o2 among other things these can drive ph down.

 

[BriDroid]

There is little to no biological processes in the bucket. Fish breath and create co2, biological processes consume o2 among other things these can drive ph down.

Duh, that makes total sense.

I also noticed that my powerhead in the bucket is breaking the water surface way more than in the tank. This morning I moved one of the outlets up to break the water surface more, and my pH has already went up to 7.9 in the tank. I'm thinking that I didn't have enough surface agitation.

 

[twentyleagues]

Duh, that makes total sense.

I also noticed that my powerhead in the bucket is breaking the water surface way more than in the tank. This morning I moved one of the outlets up to break the water surface more, and my pH has already went up to 7.9 in the tank. I'm thinking that I didn't have enough surface agitation.

That is another great possibility too depending on ambient co2 levels.

 

[rtparty]

Oxygen (O2) has nothing to do with pH.

In an aquarium pH goes up when lights are on due to photosynthesis using up CO2 in the water.

You likely have more surface agitation and even a skimmer on your display. This is pulling in CO2 of the surrounding air and driving pH down. The bucket will likely reach 7.8 once it reaches equilibrium with the ambient air. That hasn’t happened yet.

Edit: or you may not have enough surface agitation in the tank which is keeping pH down

 

[BriDroid]

Update, with the return from the pump redirected up and more surface agitation, my pH is now sitting just over 8. I thought I had enough surface agitation, but I guess I needed way more. Thanks everyone!

 

[Nomadic1]

pH is one parameter I've never chased, honestly. Maybe back when I was a new reefkeeper, I worried about it, but since mine was never "ideal" and things were thriving, I stopped worrying about it.