There is one problem with percentage water change. Simply dripping in a volume equal to 50% of tank volume does not do a 50% water change. The drips mix with the tank water and then filter out. You would have to run many times the tank volume to get a 50% water change daily. Put some methylene blue in a small container and drip in from a larger container and watch the color change. You may have to drip in 10 times or more the volume of the tank to get 50% change over.
It sounds great but it just does not get the result many people think. You also would have to use way more water to achieve the same result.