Adding water volume no sump no drill

[BeanAnimal]

Wouldn't a adjystable inline valve on one or both lines work?

No, the system has no chance of staying in balance.

 

[BeanAnimal]

You can always auto water change into another tank with a few dosing pumps.

That solves nothing here.

 

[jda]

In general, anything that does not use gravity to end in the final location can and will fail. You can never get the balance right with pumps and even if you do for a bit, the tiniest amount of film bacteria in the lines over time will mess it all up.

Gravity is it.