If skimmers removed phosphates, the phosphate media product a lot of companies push to market would be a business failure. To answer your question, I can safely say that it will not remove phosphates. It will, however, help remove the culprit responsible for the rise.
You can reduce feeding and/or adding filter feeding foods. Some foods leach phosphates. Some freshwater (tap water) will have negatively charged ions like nitrates, phosphates, etc. Check your tap water if using it with conditioner.
Try to fill us in on how your run your tank, feeding schedule, water used, dosing, equipment used, you get the idea.
The only thing I could say is to keep on the water changes and yes, keep an eye on the pH and the Alk as the changes will drop them. It will drop calcium too in some occasions.
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30g reef tank, CPR CY192 filter w/ DIY plumb running Rio 17HF return, Coralife 3x 9w UV Sterilizer, 3 24W T5-Helios 10K Daylights/3 24W T5-Helios Blue lights, 2 Logysis blue meteor light strobes (moonlights/24 Blue LEDs).
Tiger tail cuke, asst. snails/hermits, asst. feathers, rainbow acan,zoos,shrooms,bubble,galaxea, asst. shrimp, 2 ocellaris,mandarin,zebrasoma xanthurum,pink-spot watchman,red-striped pistol. | 
phosates and skimmers 
dang lazy cleaner shrimp! 
