Question About Water Changes

[Jweiner]

Should the water in a freshwater aquarium be changed weekly(ish) regardless of the nitrate level? If the nitrate level is <20ppm, can the water change be skipped or are there other reasons for weekly water changes?

 

[coralbandit]

Many other reasons to change water,but your stocking seems to be fine as 20 is ok...
Many just do their weekly as force of habbit or to grow bigger healthier fish.
I change water 2-3 times a week on my tanks...Usally 25-50% each time...
How do your fish look?

 

[Jweiner]

I have 6 Espie Rasboras, 4 Pygmy Corys, 4 Sparkling Gouramis and 6 dwarf shrimp. I have been slowly stocking over the last couple of weeks. Yesterday, the Nitrate level was at 5ppm so I didn't change the water, but now I am wondering if I should have. All my fish seem just fine.

 

[coralbandit]

you are all good at 5ppm!
Sounds like a cool little nano tank you got set up!

 

[Jweiner]

So really the only reason for a water change is to keep the nitrate level low?

 

[coralbandit]

No some fish excrete growth inhibiting hormones or other things we can't even begin to test for.
Clean water is like clean air. You can't get too much...

 

[skrapeNKA]

Water changes are also a great time to suck waste out of the tank so it doesn't build up! It can also replenish pH buffers and any minerals you happen to have in your water (unless you're using reverse osmosis water, of course!).

 

[Andy Sager]

Water changes are also a great time to suck waste out of the tank so it doesn't build up! It can also replenish pH buffers and any minerals you happen to have in your water (unless you're using reverse osmosis water, of course!).

And to expand on this, the fish use up ( absorb) the minerals in the water and even if you are using RO water, you should be adding back some of the minerals to make the water safer for the fish. As Coralbandit explained, there are a whole host of reasons to do water changes besides just reducing nitrates. Nitrates are just the end of results of the decay. if you can remove the causes before they turn to nitrates, the fish will like you much better.