Active job

Spa troubleshoot green smelly water

I have been balancing the spa chemicals for a few weeks and it’s been great. Lately it’s turned light green and has a funny smell. I have shocked it but just cannot seem to fix it. Meant someone to come and troubleshot it and fix it for me to learn. I don’t just want to hear drain it and start again. So need someone that really has the experience with spa to sort it out.