Hi there Kathy!~ Welcome aboard Trouble Free Pools.
We don't believe phosphates are of any concern as long as you keep your chlorine at the proper elevation based on your CYA level.
Chlorine kills algae. Phosphates are algae food. No algae, who cares if the food is there??
I would definitely worry about your chlorine level being 0.17....that's an invitation to algae to come have a party at your expense.
How do you chlorinate? Do you always rely on pool store tests??
Let me lay some visual aids on ya, along with some fast reads-
ABCs of Pool Water Chemistry
FC/CYA Levels
Holla back with questions
Maddie