Preparing a polyelectrolyte solution: strength, mixing and ageing
How to dissolve granular polyelectrolyte properly: strength, water, stirring and time.
A polymer that is not fully dissolved wastes money and can block pumps. Good make-up is simple but it has to be done the same way every time.
Strength
Most plants dose a dilute solution. The dosing calculator defaults to 0.1%, which is 1 g of polymer per litre. The Sunfloc specification sheets list a recommended working concentration and a maximum use concentration for each grade where stated; do not exceed the maximum.
Method
- Fill the tank to about 80% with clean water.
- Start the stirrer so there is a gentle vortex.
- Sprinkle the granules slowly into the vortex, not all at once, to avoid lumps.
- Keep mixing gently for 45–60 minutes until fully dissolved, then top up to the final volume.
Common mistakes
- Stirring too fast. High shear breaks the polymer chains and reduces performance.
- Wet scoops or damp storage, which clump the granules. Store in the original sealed bag; shelf life is 24 months unopened.
- Making up more than you use in a day or two.
Use the solution make-up calculator for quantities.
A made-up batch, worked through
Suppose a plant needs 2 kg of polymer a day. At 0.1% (1 g per litre) that is 2,000 litres of solution a day. A single 1,000-litre tank would therefore have to be made up twice a day, so most plants use two tanks, one in use while the other matures.
Add the polymer slowly into the vortex of stirred water, through a wetting funnel or eductor, so that no lumps form. Mix gently for 45 to 60 minutes and avoid high-shear pumps, which cut the long polymer chains. Use the solution the same day.
Check the dissolved solution before dosing: it should be smooth, with no fish-eyes or gel lumps. If the pump or the dosing line blocks, the lumps are the first thing to look for.
Not sure which grade suits your water?
Send us a one-litre sample or describe your process. We test it in our lab free of charge and recommend a grade and starting dose.