Rinsing marco rock ans ph increase

[Van Eternal]

Hi guys,

I bought 30 kg of dry marco rock to put in my new tank , but before placing it in the tank I had decided to rinse it in a water butt in RO water. I let it sit there for about 3 days and tested the ph and to my surprise the ph was above 9!

Is this something normal?

 

[lapin]

Sounds normal. Ph will change a lot when the rock is comming alive