Alum

Dual purpose HASA Alum may be used as an additive to sand filters to improve filtration or can be applied directly to the pool as a floc. When added to a sand filter, Alum coats the filter bed and traps smaller particles that the sand alone cannot.

When severe water clarity issues occur, it may be easier to “floc” the pool. This process drops the suspended particles to the bottom of the pool which are then vacuumed to waste, rather than filtering.

Sand filter additive instructions:

1. Add Alum directly to the sand filter by slowly pouring the powder into the skimmer.
2. Use 1 pound of Alum per square foot of sand filter area. Consult filter manufacturer’s label to determine filter’s square footage.
3. Repeat process after backwashing.

Flocculation instructions:

1. Adjust alkalinity and pH. Floc works better at a higher pH range (7.6 – 8.0).
2. Run filter for 1-2 hours after adjusting pH.
3. Shut off  filter and all other pumps.
4. Broadcast Alum over surface of pool as evenly as possible.
5. Use 2.5lbs. to 5lbs. of Alum for every 10,000 gallons of pool water. The rate depends on the amount of suspended particles.
6. Leave all pumps off for 6-12 hours, allowing the Alum and sediment to settle to the bottom.
7. Vacuum pool to waste (sewer or as directed by local regulations) to remove floc sediment. Do not disturb water more than necessary so sediment remains on the bottom.
8. Test and rebalance water.