Please suggest a dosing pump

[Delphinus]

How much do you want to spend? A fairly low-cost approach would be two Aqualifter pumps and a digital appliance timer (or two). If you can add the effluent lines to different spots in the tanks you can have them dose at the same time. If you prefer to drip the effluent in the same spot then you need two timers (so that you can add them at different times). Use one minute intervals on the timer (hence the digital timer) and you should be set.

I never tried the controllable Aquamedic pump but I did once try a noncontrolled one (ie., using my own timer) for dripping kalk but I can confirm the rollers did not pinch the tubing hard enough to prevent seeping during the off cycles (ie., either forward flow OR backward flow, depending on which direction the head pressure was). The only way you could use an Aquamedic, in my opinion, is if you are lifting the water into the tank (so no chance of uncontrolled flow during the off cycles) AND the effluent line had no chance of being submerged (ie, so no chance of backflow during the off cycles). Do-able mind you, but something to keep in mind. I wasn't able to use the pump because my kalkreactor was taller than my sump so there was a constant slow drip during the offcycles.

Another option is the LitreMeter3, they've been around forever, but they are pricey. Both BRS and MOPS come to mind as places you can pick up a LitreMeter3. BRS also sells the "Drews Dosers" and the Aqualifters.

HTH!