Why did the PH rise?

[Karen Garza]

Four days ago I added 9 Spiral Vals to my 20 gallon freshwater tank. (those
are the only plants in the tank) I also added 10 ml of Leaf Zone plant food
as per the instructions. Before adding the plants and plant food the PH was
about 8.0. I just checked my PH again and now it's 8.4. What's going on? Is
the plant food causing the PH to raise? I have a bubble wand, a Penguin 125
HOB biowheel filter, and two pieces of drift wood in the tank. The substrate
is plain old aquarium gravel that I bought at Petsmart. I have added The
inhabitants are as follows:
5 Platys
3 Corys
2 Otos
18 Platy fry

Ammonia 0
NO2 0
NO3 2.5

Thanks

Karen

[Steve]

Karen Garza wrote:
> Four days ago I added 9 Spiral Vals to my 20 gallon freshwater tank. (those
> are the only plants in the tank) I also added 10 ml of Leaf Zone plant food
> as per the instructions. Before adding the plants and plant food the PH was
> about 8.0. I just checked my PH again and now it's 8.4. What's going on? Is
> the plant food causing the PH to raise? I have a bubble wand, a Penguin 125
> HOB biowheel filter, and two pieces of drift wood in the tank. The substrate
> is plain old aquarium gravel that I bought at Petsmart. I have added The
> inhabitants are as follows:
> 5 Platys
> 3 Corys
> 2 Otos
> 18 Platy fry
>
> Ammonia 0
> NO2 0
> NO3 2.5
>
> Thanks
>
> Karen
>
>
The plants use up carbon from the water, causing reduction of carbonic
acid component of the carbonate buffer system ( :) making this up as I
go :) ). That causes a rise in pH during the day, or so I've read and
also observed when I had hard, carbonate-rich well water.

It may also take tap water a while to settle to a stable pH due to
outgassing, etc.

Steve

[Karen Garza]

"Steve" > wrote

> The plants use up carbon from the water, causing reduction of carbonic
> acid component of the carbonate buffer system ( :) making this up as I
> go :) ). That causes a rise in pH during the day, or so I've read and
> also observed when I had hard, carbonate-rich well water.
>
> It may also take tap water a while to settle to a stable pH due to
> outgassing, etc.
>
> Steve

Thanks Steve
I am on well water. I think I need to do a few experiments with the water.
Maybe my water is hard and carbonate rich. I am hoping it will settle to a
lower PH over time.

Karen