I have a 3 gallon tank with a sponge filter and a couple of live plants.
I've been doing a fish-in cycling for about a month, and I think my tank is finally cycled since it doesn't show any ammonia or nitrites, but small amount of nitrates.
Just to set up a proper water change schedule, I am monitoring how fast the nitrates build up. It's been 9 days since the last partial water change, but the readings are still ammonia=0, nitrites=0, nitrates<5ppm.
So, my question is... do I still need to change water regularly, like once a week (~50% I presume), or can I just wait until the nitrates reading becomes higher than 5ppm?
At this pace, it seems like the nitrates level will not exceed 5ppm in 2 weeks, maybe due to the live plants in the tank consuming it as fertilizer.
To put it another way, in a cycled tank, is the water change just to dilute down the nitrates level, or is there any other reason?
Thanks a lot in advance.