Please note this is in the scientific section and my general recommendation of 50-75% weekly water changes still applies.
Now that's out of the way I am setting up a new blackwater tank and aiming for very soft acidic environment and would be happy if the pH could get to around 4 but will not add anything to the water to achieve this.
In my community tank I use RO, have bogwood, have a good number of plants and am heavily stocked. Ideal conditions for a low pH. But the tank never drops below 5 - according to a digital tester its typically around 5.3. In this tank I do regular 75% weekly changes and we know that this contributes to a stable environment.
Much of the guidance on very softwater fish suggests water changes of no more than 25-30%. I do believe that large changes are still beneficial as long as performed regularly with stability being the key.
But...
Now that's out of the way I am setting up a new blackwater tank and aiming for very soft acidic environment and would be happy if the pH could get to around 4 but will not add anything to the water to achieve this.
In my community tank I use RO, have bogwood, have a good number of plants and am heavily stocked. Ideal conditions for a low pH. But the tank never drops below 5 - according to a digital tester its typically around 5.3. In this tank I do regular 75% weekly changes and we know that this contributes to a stable environment.
Much of the guidance on very softwater fish suggests water changes of no more than 25-30%. I do believe that large changes are still beneficial as long as performed regularly with stability being the key.
But...
- Is there a case for keeping a light stock level and reducing the weekly water changes to 30% to allow the pH to drop further?
- Is the assumption that pH would continue to drop naturally (with these smaller changes) due to natural biological processes correct? The source water has 0KH so there is no buffering
- If the above 2 items are correct is there any detriment to doing a larger monthly change of say 75%. Besides my natural obsession with clean water my thinking is that this will prevent the pH dropping out of control and keep it at a level where it would still be safe to perform an emergency water change (if needed) without shocking the fish.