Pool Green Not Algae

Hello,

I stripped a sealer off of travertine pavers on my pool deck and now the pool is green. The green is definitely NOT algae. I took a sample to my local pool store and had the normal tests done, plus tests for iron, copper, phosphates, etc...basically everything they can test for. All was normal, except that I needed two cups of acid. I have explained the situation to them and showed them pictures. Their advise was add the two cups of acid and wait a week and see what happens.

I do have a spa heater that I let a small amount of water flow through constantly that does have a copper nickel heat exchanger. This was not valved off and stripper did get in the pool water but given that we don't find any copper, I am not sure how that can be it. I had a chemist look at the contents of the stripper which are all organic ether based materials and he said that should not touch copper.

Any ideas on where to go next? thanks