Medstudy,

You seem to be bypassing the advice to put chlorine in your pool. Is there a reason for that? Is your water still clear?

Nevertheless, I would suggest you raise your Cl in the evening to 30ppm. Then retest the next morning. If you have lost more than around 2-3ppm, you have lost it to organics in the pool and you must keep killing them.

Bring it back up to around 25-30 each evening 'til your Cl holds overnight and then let it drift down into 4-8ppm range. That cure the issue. To do this correctly you will need a test kit that tests Cl for levels that high and accurate calculations and dosage to obtain the proper level.