Originally Posted by jargonchipmunk
the 50% WC is NOT for the fish. For the fish no water changes are needed in heavily planted tanks. The plants are all the nitrate control you'll ever need.
I would be careful as to what you say.
IMO, MAYBE you can get away with "no water changes are needed in a heavily planted tank", if you MAYBE, I doubt... had a limited stock of fish.
People are going to take your words literally, stock up their tank with
what they think is "heavily" planted, and think they are set.
An ESTABLISHED planted tank that has been running for at least 12 -
18 months, using their plants as a "biological" filter takes years to do.
Anyhow, IMO it is ridiculous not to do any water changes in a tank with something living. Most people in this hobby aren't going to be able to do that cept for maybe Tom Barr and a few others.
There is no rule as to how many water changes you should do in your tank, planted of otherwise. But, I would say, most would agree that there needs
to be SOME KIND OF WATER CHANGE, at least to get the bacteria and
anything else out of the bottom of the substrate that would build up after a years time and not break down.
To answer the original Q to the poster... you don't wait until your ammonia and nitrates are high before you do a water change. You will stress your fish out, and take the chance of disease and death.
You want to keep your water parameters stable, which IMO will be virtually impossible with no water changes cept for someone besides an "expert", who has unlimited resources with money, time and lots experience.
Sometimes I wonder if people who are "into" the planted tanks care more about their planted tank, then the living, breathing fish in it.