Questions regarding extended water change interval
I'm not aiming for a no-water-change tank, but just want to reduce the frequency if it will make everything more stable for my shrimps. Questions are:
1) I read about creating anoxic conditions to convert nitrate to N2, but why not just use floating plants plus removing them to control the nitrate level?
2) How to deal with or test for the general case of "pollution", whether it be from poop, uneaten food that fell into the substrate, little bit of plasticizer leeched out, "bad" bacteria, some mineral accumulating, etc. There are so many ways to add bad things to the water, yet it seems that the no-water-change philosophy depends on plants and bacteria to remove them all. Really?
3) What is the shrimp feeding philosophy here? The standard is to feed sparingly and remove uneaten food promptly, but now am I no longer supposed to fear "pollution" from leftover food?
4) Do I still add fertilizer (ThriveS) for the plants, or not, since I can control the nitrate level.
For background, I have a low-tech shrimp tank which has UNS controsoil, a few plants and mosses, and I typically do 15% weekly or once-every-two-weeks water change with RO water + GH remineralizer. Usually things are ok and nobody dies, but sometimes the shrimp become less active than usual. Since I am new at this, and the tank is slowly changing with time, there are little changes along the way, such as installing a new light, trying a new food, oops I added too many Indian Almond leaves and turned the water brown, etc. And so my usual fix is to the change the water more often, since I figure that the new water I put in is about as clean as possible.