PH raised singnificantly

[Bayo]

Need your words of wisdom.

i have a 6gal tank fully cycled. The last water parameters (yesterday) are the following:

Ammonia: 0
Nitrite: 0
Nitrate: 8
PH: 7.6

Every time that I measure the PH is around 7.0 but yesterday I found out it was 7.6. I did not do any change in my tank, what could be the possible reasons for the PH to rise?

Thanks!

 

[Andrew McFadden]

something in your tank is buffering it up or the water you use for water changes has changed.