The only extra water my little hex tank receives is from top up through evaporation. It's not a lot but enough to replenish some of the lost elements/nutrients. And the tank is thriving, crystal clear water showing constant 0ppm nitrate.
If it had a tight fitting lid on, which I can't possibly do because of the plants, then I wouldn't have to top it up at all. In that scenario I'm not sure what would happen long term. Would the balance still be ok or would part of the ecosystem break down and cause me problems? I honestly don't know the answer.
I just absolutely love this tank and can't wait to set up more smaller tanks when my 360 goes.
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