But I can't figure out, how often and how much for water changes? Will water changes in this circumstance harm the system more than help it? What do you think?
This got me thinking. Why not write a post on the do's and don'ts of water changes in the planted aquarium? So, here they are:
Do change 30-50% of the aquarium's water every 1-2 weeks. This is variable based on fish load and filtration, but not on the aquarium's size. From 1 gallon to 100 gallons, 30-50% is a good rule of thumb. This removes all the toxins and excess nutrients that build up in the water.
Don't rely on filters to clean the water. Filters don't remove excess nutrients and toxins from the water, they just trap it so it can be removed easier when you clean your filter. However, filters also can't remove many things effectively.
Do make sure the water you use to fill the aquarium back up is the same temperature as the aquarium water. Drastic changes in temperature stress the fish and can lead to disease and even instant death in extreme cases.
Don't forget to add a water conditioner that removes chlorine and/or chloramines if you are using tap water. These can kill fish and even plants if not removed. Water conditioners also often remove heavy metals such as copper that may harm plants and fish.
Do water changes after courses of medication, after stirring up the substrate doing a re-scape, or after accidentally overdosing anything, including fertilizers. Water changes help to "reset" the aquarium by removing dissolved waste and chemicals. They are often a cure-all for many aquarium related problems, and rarely cause harm if done in moderation.
Don't remove more than 50% of the water during a water change if you can help it. Sometimes, more than 50% is needed in extreme cases (such as ammonia spikes or overdoses), but this can put stress on the fish and the beneficial bacteria in the aquarium. It can lead to rapid changes in water parameters (such as pH) that are as stressful to fish as rapid temperature changes.