What happens to ROI when you refi and reinvest all money back into property?

[Marco Gonzales]

I purchased a property for 600k. It originally produced 100k per year and nets 50k so my cap rate and ROI would be about 8%. I got a mortgage for 200k to rehab the place. My new net income (after mortgage) is 70k now because of increase rents. If I am going to calculate my ROI and Cap rate, am I using the purchase price of 600k or do I use 800k because I pulled a loan out for 200k and reinvested it all into the property? I understand this may be a stupid question.