How do I achieve the maximal dosing accuracy with GHL Dosers?

In order to achieve the maximal dosing accuracy with our dosing devices we recommed:

  1. Always use the newest firmware for your device resp. the newest version of the PC software GHL Control Center. Please update to benefit from our on-going improvements. You find the newest version in our download section.
  2. Select the appropriate pump speed. The smaller the dosing amount and the higher the required precision is the slower the speed shall be. For large amounts which don’t need a very high accuracy higher speeds are appropriate.
  3. The calibration process is extremely important. Calibration has to be made in the speed in which the pump will later be operated, of course. For calibration the hoses should be as short as possible, the total length shall not exceed 60cm (2ft). The volume, which is pumped during the calibration, must be measured absolutely precisely. We recommend a letter scale or appropriate vessel with exact markings.
    Check the calibration: Dose a certain amount and check whether the expected quantity was also dosed. Repeat the calibration if the result is unacceptable. The test amount should be large enough for the pump to run for at least 1 minute.
  4. Keep all hoses as short as possible. Use the smallest possible inner diameter which just works for your application. The larger the volume inside the hose – determined by inner diameter and length – the less accurate the dosing will become.
  5. Avoid large height differences between dosing container, pumps and aquarium. The smaller the differences the more accurate the dosing will be. The dosing container shall be placed below the water level to avoid a back flow or syphon effect, the outlet hose (to the aquarium) must never hang in the water.
  6. Although the pump heads had been produced under highest quality standards with very small tolerances it can’t be guaranteed under every possible operating condition that liquids move in the hose after a certain time. Therefore it is possible that reverse valves improve the precision. But this will only work if 5.) has been followed, especially important is that the dosing container is below the water level.
  7. Bear in mind that liquids in the tube may volatilize, depending on temperature, air pressure fluctuations and last but not least on the fluid itself. Also, gases can diffuse through the tubing and create bubbles in the tubing. If you have problems with bubbles or liquid seems to return, you should change the tubing. In particular silicone tubes have a higher gas permeability.

 

Bottomline – You achieve the best accuracy with:

Slowest possible speed, very precise calibration, thin, short and gas-impermeable tubes, small height differences.