If you boil the lines, then pull straight, they won't curl. I use silicone tubing which naturally hangs pretty straight down. I dose into the chamber which overflows from a refugium into my main return, so the flow is pretty high. I also have a powerhead in my main pump chamber to mix up everything, and give my coral I am storing down there some more flow.Do you have a solution for the tubes curling?
I use the same thing, issue I always have is the airline tubes curl a bit and I always end up dripping solution against the back of the tank and it makes a giant mess of precipitation.
Was thinking when I eventually get the pump going again I need to connect some ridgid tubing to the airline.