To Answer my own question and to share with the community the team at BRS and Tunze replied as follows;
"The pump speed is set by voltage, 12V is full power, 9V will work but slower, 6V is the bare minimum to work. At 12V each pump can draw as much as 1200mA. The Osmolator only lets the pump have a max of 1200mA before detecting it as a failed pump and cutting off power to the pump."
I used a couple of the pumps for my DIY top off on both of my quarantine tanks using 2 float switches wired in series and a mechanical float valve for each (double redundancy). I used a switchable 3-12 V power adaptor set at 9v for the power to the Tunze and a 24v power adaptor for 2 relays that control the pump via the float switches. A cheap digital timer switches the power on for one minute every 4 hours (which is another level of redundancy). Both of the power supplies and the timer control both of the top offs. I did think to add solenoids so that I could run it all of one pump, but did not want to over complicate it. I do have my DOS adding ALK & CAL to both my DT and quarantine using solenoids, buts a different story. If there is interest and anyone would like me to post pics or either of these projects, just let me know.
