What are your phosphates at with that Rx product? And how long does the bottle last?
A bottle contains 600 drops or treats 1000g. I use it about every 10 weeks, so 5x a year. I believe I use about two bottles a year. When PO4 measures .25ppm, then I'll dose the tank and bring it back down to 0 overnight. It's super easy to use, just drip it into the skimmer section after lights out while the fish are sleeping. By morning the water will be crystal clear and you can test PO4 to see if it got it all or not. Recently this year, BlueLife USA started offering 10micron filter socks to use with it, so that will work even quicker trapping the flocculant in two hours flat. This is practical if you have a show tank that can't be cloudy due to public viewings.
I have a 400g system with a 60 anemone cube. It's a mixed reef with about 50 fish or so.