I'm not a Walstad Method expert, although I've studied it. My approach might merely be called somewhat Walstad inspired. But I think even a Walstad Method expert would have difficulty with your question not knowing how many fish you may need to grow out in the 10g tank.
Granted that Guppies are quite small, but the numbers could matter.
In any case, I assume if you're closely following the method that you are not using chemical additives (ferts) and you're not doing water changes. With an increasing number of growing fry, it would seem logical that you may need to do modest water changes to maintain the balance. Would that be so bad really?
Frankly, I think that's one area Walstad got it a bit wrong. Although it's somewhat important to preserve the organic nutrients for the plants, nature refreshes fresh water all the time with rain and run off...so doing small partial water changes in the aquarium just seems most natural and appropriate.
Granted that Guppies are quite small, but the numbers could matter.
In any case, I assume if you're closely following the method that you are not using chemical additives (ferts) and you're not doing water changes. With an increasing number of growing fry, it would seem logical that you may need to do modest water changes to maintain the balance. Would that be so bad really?
Frankly, I think that's one area Walstad got it a bit wrong. Although it's somewhat important to preserve the organic nutrients for the plants, nature refreshes fresh water all the time with rain and run off...so doing small partial water changes in the aquarium just seems most natural and appropriate.
