To add to Eric's post, there's no quick fix here and water changes will never get you to the point where things are normal (in the short term). Too many water changes can cause more harm than good.
I would take to using an actual refugium long term. This would include a deep sand bed along with chaeto or your macro algae of choice. Buy Ron Shimek's book "Sand Bed Secrets" on amazon and give it a read through. Using a DSB is the secret to long term nutrient control and biological diversity. One of my most successful tanks was my 15g/10g display/refugium in the 90's. It was powered by a 150w Iwasaki 6500k metal halide and was filled with corals and gorgonians. I only kept a handful of fish in there, one of them being a spotted madarin. It never ran out of food because of the refugium produced so much food (pods) that I kept a pipefish in there as well. But to my point, I never had algae problems, corals grew like crazy and that system thrived. I'm resetting my 90g now and I'm going to use a DSB in the sump. DSB work, but you need to set them up properly and leave it alone.
I will add this, buy a few bottles of PNS Probio and start using it weekly. Your nutrients will start to come down and your corals will thank you. Also, buy a bottle of PNS Yello Sno and use it once a week at half the recommended dose. This will provide food for your corals and also vitaman b12 for the bacteria to thrive and do its job. My PO4 was running too high in my tank and after using PNS Probio/Yello Sno it turned it around. The other thing you can do is use Eco-Balance, but split the dose up over the course of the week and not a one-time dose.
I know this is a lot to take in, but it took a long time for your nutrients to rise this high, so it's going to take that long to drop/reduce, as it should. I'm always a proponent of natural ways of running/maintaining a reef and I've never been one to use chemicals to do a job that nature can do on it's own. Chemicals work when they are absolutely needed, but they shouldn't be used all the time. I will also add, don't cut food drastically, but be aware of how much food you're adding when feeding your fish. Add smaller amounts over the course of the day if you can and also make sure that the food is eaten and not floating past your fish.