onyx sand raise PH?

[wigglejaggles]

hey now all,

well I am testing the water in my new tank. It is a 10 gallon, and I used onyx sand, one 15 pound bag.
I tested the PH directly out of the tap and it is 7.0 I have now tested the ph from my tank and it is coming up 7.4 I even used the high range PH test to see if my eyes were tricking me. Sure enough my tank reads 7.4
Another odd thing is that my GH is reading 35.8ppm

How in the world do I have alkaline ph with soft water? Is it possible?

I am thinking the onyx sand is raising the Ph. Let me know if you have had any other similar experiences with the onyx.

I wanted to have cardinal tetras, but I am thiking 7.4 is just too high for them. :-(

Here are my complete tank conditions:
PH-7.4
GH-35.8
KH-between 35.8-53.7---had a hard time determining what was bright yellow. 35.8 more translucent yellow, 58.7 more solid yellow.

With these conditions will I be in danger of any rapid PH swings?

thanks all!

take care,
Jared

 

[RTR]

Testing pH directly from the tap has little meaning for how the water will stabilize in the tank. If you want to test the tap water you need to age it in bowl at least overnight or aerate it for 30+ minutes to blow off excess dissolved gases and get it to room temp.

Yes, onyx sand does buffer the water slightly when new, less when it is older.

Your Cardinals will be fine with Onyx sand.

Edit: Your KH is still too low for CO2 addition.

 

[wigglejaggles]

thanks

Hello,

Thank you for your insight. So what do I do if I want live plants? I just have to accept the fact that my water cannot deal with co2 injections? I guess just choose some hardy easy to grow plants...?

just now I tested Ph from tap water that has been sitting over nite. Came out as perfect 7.0, so the onyx is def raising it. One would think it would raise the KH as well?

thanks!

take care,
jared

 

[RTR]

You can raise the KH of your water to 3-4 degrees. This will raise the pH as well, but CO2 supresses pH anyway.