Lillybella -- LionPrincess is using optiphen as her preservative. I am using ethyl alcohol (EtOH) as my preservative.
I don't quite remember how much EtOH is recommended by the experts for effective preservation of commercial products such as this room spray we're talking about. I estimate the EtOH should be at least 15% to 20% by weight in the finished product, going by my experiences making tinctures, wine, and mead. You'd want to double check and follow the experts' guidelines, however, if you're going to use EtOH for preservation in products you will be selling or giving away to others.
LionPrincess -- I'd gradually add more PS 20 to your room spray until the mixture clears. It's nice if you can mix the PS with the EO first, mix until the two are a uniform mixture, and then add the solvent (meaning the EtOH and/or water mixture). But you can add the PS to the finished mix if needed while you're trying to figure out the proper ratio.
What I've learned is that many recipes gives a single ratio of PS to EO, as if there's only one answer possible, but I've learned otherwise -- I pretty much use the recipe's ratio as a rough guideline.
I generally start with 2 parts PS to 1 part EO and work up from there -- 3:1, 4:1, etc. At some point, the liquid will turn from milky to translucent. With a bit more PS, it will turn from translucent to clear. It's kind of cool to see the change (except I get frustrated with how much PS 20 I usually have to add!)
What I have noticed too is sometimes a mixture may be slightly translucent at first but will gradually clear on its own -- it might take a few days. If I have the patience, I'll let a translucent mixture sit for a few days and see if it clears on its own. If not, a dab more PS will do the trick.
There are other polysorbate products -- for example, I know there's a polysorbate 60. PS 60 might work as good or better than PS 80, but I haven't tried it (yet).