went to balance the water on the spa at the place Im renting the chlorine reading was at 3.0, the TA was at 100 the Ca was at 170 and the Ph was at 7.0 I went to add Ph increaser and the whole spa turned a deep blue it took a few days for everything to get back to normal. can anyone please tell me what that was all about

This sounds like copper in the water . When you added the soda ash the ph bounced up quickly and metals started to come out of soluition. Be carefull this could stain the spa walls. I would drain and alwasys keep ph above 7.4. Erik