I'm also not sure where people got the idea that 10% weekly is the norm or what's apparently recommended as a rule of thumb. I don't believe this to be true, as far as I know 10% monthly is what's recommended as a rule of thumb to simplify things for beginners. From there each hobbyist determines what works best for them, whether it be more or less depends on their tank demands and experience. Systems like Zeovit call for a 10% change weekly but there are specific reasons for this.
This is not a new concept, it's how it's always been so if people are debating whether to change X amount weekly or Y amount monthly or even Z amount quarterly you're really all doing the same thing. Changing water, the amount and frequency is only thing different.
Eliminating water changes all together is different story but it's also nothing new and been going on for decades. It's not new technology that people haven't adapted yet, it's simply a different method that few people use long term for what I believe is the simple concept of excess organic and inorganic impurities that will build up over time as well as imbalance of elements.
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