I am useing Nature 2 test strips and as of now I put in Spa Metal Out in it and then cleaned the dirty filter.Now testing it i was a little low on the PH so i put some Spa Ph Increaser in the spa and now its at7.4 and the ALK is at around 90.Only thing is on the Test Strip the MPS still stays white and does not chage color at all.My friend says I should not Shock it at all.I also have the Nature2 Spa Purifier in the filter too.Now is my spa ready to use or do I have a problem with the MPS?Johnny Thunders :-/