I agree and there is far more people who would agree with this. I'd rather change water than add another piece of filtration that can fail. Comparing the removal of ammonia and nitrite to the removal of nitrate is not apple to apples even though they can all be reduced via a water change.
I've had my best success with a heater, ATO and weekly water changes. No other mechanical filtration.
It is interesting how ingrained water changes are in the hobby when so many things show they are one of the least effective methods for nutrient export and element replacement. I would say if you have a smaller system (less than 100 gallons) it is probably extremely effective and that might explain how this thinking came about. I bet most of us started with small aquariums and upgraded so our practices and habits stick. The days of water changes to manage alkalinity and calcium levels are long gone but for some reason, water changes to manage nutrient export are still the norm.
I am going to use my situation as an example and I know my situation is not unique. My nitrates were in the 50 to 60 range, PO4 close to zero. I was feeding my fish the bare minimum out of fear of contributing to my nitrate issue. I have a fleece roller so filter socks are not an issue. I want my nitrates to be near zero. To achieve that using the water change method I would have to start by doing a 90% water change (315 gallons) which would cost $150 of salt and require four days of RO production (roughly 4 gallons per hour and I have to monitor it so no overnights). That only gets me to about 5PPM then I have to do 50% water changes on weekly basis at a cost of $75 per week of salt just to maintain 5PPM which is still not near zero. In my scenario, it is $375 in month one and 10 days of effort to not achieve my goal with a $300 a month and 8 days of effort per month ongoing. The cost and effort just don't make sense. Sure I could upgrade my RO capability and cut the days in half but it is still an insane effort for the result.
Using bacteria for nutrient control, just like we do for Ammonia and Nitrite control, I spend $300 on a reactor, $12 on a pump, $50 for media totaling $362. It took 20 minutes to set up and five minutes each time I adjusted the flow rate for a total of one hour and twenty minutes spent in month one. I pretty much never have to touch it for two years where I will spend $25 on sulfur media. I also add 8 teaspoons of soda ash each week for alkalinity and pH. In my situation, it is an easy choice. I understand why for a much smaller aquarium the economics are different but the convenience is still there.
I do think more people should consider alternative nutrient export methods because they just make sense.
As it relates to a piece of hardware failing, I've never heard someone say "I shouldn't get a return pump because it might fail." or "I shouldn't get a protein skimmer because it might fail." So why would this piece of equipment be any different?
My goal is not to put done people who do water changes but instead provide objective data points in hopes of making people aware of alternatives that for most should be more effective and cheaper.
