Are frequent aquarium water changes really necessary?

The Short Answer is Heck Yes! But What the Heck Does Frequent Mean?

The ideal water change percentage for marine, reef, freshwater, and freshwater planted tanks is 10-15% per week. This schedule can very challenging for the average aquarium owner. As a family man with a busy schedule, I must admit that there are times when I’m unable fit in that weekly water change. I strongly believe that frequent water changes have been key to my success in keeping expert-only fish and coral. I also believe that frequent water changes will determine a beginners success within the first year.

If you don’t have the time to do 10-15% weekly water changes, or 20% biweekly water changes, then the bare minimum I think you and your water buddies can get away with is a 20% monthly water change. If its been a month since your last water change, then I recommend that you only do 20% (25% max) water change. The reason for this is that more than this amount can make big changes in your water parameters and stress your aquarium friends. I’m sure you’ve heard of the aquarium owner who did a very big percentage water change and had losses or a total loss. We’ll talk about emergency situations in another post.

This can be a somewhat controversial for some, especially for the very small percentage of aquarium keepers who have managed to keep their parameters in-check with top offs only. In my experience these have been very large well equipped systems or somewhat smaller well equipped systems. The common factors were that they were very well equipped, monitored, and maintained (besides the water changes). These factors generally mean very expensive setups.