This is my first and probably only pool. Water was put in 6 days ago. It is a fiberglass free form, 15,000 gal. The water looked wonderful, then the concrete crew came to do the coping. As the person worked his way around to do the brush finish, he kept dipping the broom into the pool to rinse it off. After he left my beautiful water was so dark I couldn't see the bottom. I have run the filter (cartridge) since he left, stopping it only long enought to take it out and hose it off. My question is what do I need to be looking for? I have the Goldline SWG and the PB said it should take care of everything, but that doesn't make sense to me. He gave me a small water testing kit but have not used it yet. What should my first steps be? Thanks.