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

[[email protected]]

Try running the light a little longer. Plants will raise the pH if they
are left in the dark too long. Photosynthesis takes place only when the
light is present ... in the dark plants may create a CO2 spike.

But before jumping to any conclutions, try taking about a litre of
water and adding a few drops of the plant food in it. Test the pH
before and after to see if that is playing any role.

To test the role of the plants themselves, test the water as the lights
turn on, and as they are turning off. From what I know the pH should be
higher in the morning, than it will in the evening.

Good luck with that.

Ed K.

[Charles]

On 11 Dec 2005 05:50:38 -0800, wrote:

>Try running the light a little longer. Plants will raise the pH if they
>are left in the dark too long. Photosynthesis takes place only when the
>light is present ... in the dark plants may create a CO2 spike.
>
>But before jumping to any conclutions, try taking about a litre of
>water and adding a few drops of the plant food in it. Test the pH
>before and after to see if that is playing any role.
>
>To test the role of the plants themselves, test the water as the lights
>turn on, and as they are turning off. From what I know the pH should be
>higher in the morning, than it will in the evening.
>
>Good luck with that.
>
> Ed K.


Are you sure about that? I believe plants raise pH in the light by
removing CO2 and let it go back down in the dark by releasing the CO2.