Wgat Is Causing This ?

[Zachary1941]

Hi,
My tap water is 7.4 ph and remained at that in the tank during the fishless cycle (did rise at one point to 8.4 but dropped back 3 days later.). Which went text book style...Now i have no wood, and only one real plant the rest are fake...Yet the water Ph is always about 8 to 8.2....Have just tested both tap and tank water and once again thats the reading i get.. When i do the weekly 25 to 30% water change the tank ph is then 7.4.. But for some reason over the course of a day or two so it rises to 8+ What could be causing this please ? All other readings are perfect.. 0 Ammonia 0 Nitrites and 20 nitrates .

Regards Zac

 

[meguro]

What substrate do you have? Do you have any rocks or shells etc.? Are you dosing fertilisers?

 

[drobbyb]

Sounds like carbon dioxide (co2) in your tap water.

 

[Bebobb]

Is there anything that would release minerals i.e. fertilizers, rocks, crushed coral and the like.

 

[Truck]

whats your KH?