your water change % and frequency will depend on your tank. If your tank has a good ratio of plants and the water is balanced, you may only need to change it twice a year. If you have less plants and your water gets funky quickly, you will have to change it more often. 50% weekly is about as much as you would need to change it. It helps put good stuff in your tank and take out bad stuff in your tank. look at your plants as if they are your doctor report. you are the PHD MD DR. tank master. use your understanding to determine how to prescribe the water change.I have a +- 10 gallon planted tank in my office at work, high pressure CO2 and am dosing EI. Because of the way I'm situated (right across the hall from the men's room) it's much easier for me to do a small (10%-15%) daily water change than to do a weekly 50% change. I have a little Tupperware container that holds about a half gallon of water, for small water changes I scoop out a couple of containers full of water, dump them in the john and re-plenish, it takes me about 5 minutes. For a large water change I've got to drag in the big 5 gallon bucket, it's more hassle and also a bit more disruptive. If I do a small water change each morning before dosing my ferts, will it work out the same as doing a weekly 50% water change? Thanks.
i would say a 50% water change every month would be a better place to start. changing the water too often will let the algae thrive off the sudden changes while your plants are always struggling to catch up and adapt to the new water parameters.