P.H. swings

[Jrquicker at aol_com]

I just started up my 75 gallon fresh water tank, I inject co2 and I am 
wondering about p.h. swings. My co2 is timed to go off with the lights and I 
maintain it at 6.8 without any trouble, but after bieng off all night it 
rises to 7.2. I am wondering if this swing will be ok when I do add fish to 
the tank?Thank You 
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