Are Water Changes really necessary

[cornelius85]

I am a new hobyyist. I setup my first tank two months ago. And added fish 3 weeks ago.

First 3 days there were amonia fluctiations. After that, amonia(0ppm) nittrite (0ppm) nitrate(10-20 ppm) stabilized.

I've  been testing every day and so far so good. I have not done a single water change in two week.

Is this wise? Should I still do a 20% water change every week? My tank is well planted.

Edited November 14, 2020 by cornelius85

[KoolFish97]

Well, yes and no to are they necessary. Your current conditions that your testing for is good. 20ppm of nitrates is great for plants just as long as its not skyrocketing higher as that just leads to crazy algae growth. 

With planted aquaria you generally do a fair less amount of water changes as they are natural filters that literally remove the waste not just convert it like the standard filter. But some things you don't test for like minor trace elements, carbonates and minerals can be used up by plants and sometimes it's just worth a small water change to freshen those up if your water source has any. Sometimes to your water can get a slight colouration due to tannins and other dissolved organics and a small water change can help clear that up super easy. 

In short in a well planted not over stocked aquarium you don't have to water change all that much if really at all. But it doesn't hurt to do once every so often to boost some of those minor elements and clear up the water.  But topping off can sometimes do that anyway! 

Just always be sure to keep an eye on your levels when there to high for your liking then water change. But nitrates of 20-40 are good for planted tanks.

[Ken Dyer]

Great advice from @KoolFish97 and the only thing I would add is also watch your fish & plants. If they start to show signs of distress a smaller (~10%) water change and then continued observation can help a lot and save you and your fish the stress of rushing to medications. Most of the time your tank will sort of tell you what it wants for a water change schedule. Everything healthy and thriving, don't fix what isn't broken! Fish flashing or sluggish, plants showing pin holes or leaves less green and vibrant? Small water change and observe.

We're setting up little closed eco systems, the closer we get it the less we have to mess with it. But finding that balance can be tricky as your plant/fish loads will change over time with growth and reproduction.

My experience anyway. Some of my tanks almost never get a water change, some get them more often as I still haven't found the balance in them.