Balance the chemistry to normal levels.powder can also be used in small quantities as a filter aid for sand pool filters. Sand filters however, have large enough spaces between the sand grains, that most of the alum flushes out easily during backwashing. or Cartridge filters, as it can clog the small pores of the fabric, and ruin the filter media.
#POOL TIME SINK TO CLEAR FLOCCULANT HOW TO#
HOW TO USE ALUM as a FILTER AID for SAND FILTERSĪlum can be used in small quantities in a sand filter, to improve filtration temporarily. Alum is most active in warmer water temperatures of 70-80°, but also works in colder water temperatures.If there is algae present, you can add 2-4 lbs of shock per 10,000 gallons, immediately after adding the Alum.If your pool pump is on a timer, remove the ‘ON’ tripper, so that the pump won’t come on in the morning, and clog your pool filter, or disturb the settled alum.
Depending on the amount of solids in the pool, effective dosage can be 2 lbs to 8 lbs per 10,000 gallons.
The dosage of 4 lbs per 10,000 gallons is an average amount. You can use any kind of Aluminum Sulfate (aka Aluminum Sulphate) – food grade, technical grade or garden grade – just be sure not to use Ammonium Sulfate, which is a different chemical. Use a pool brush instead to create circulation in the pool, and help distribute the alum. If you don’t have a multiport valve, don’t run the pump after adding the alum, as it will clog your filter fast. Add a hose to the pool to replace water lost to vacuuming to water. When vacuuming to waste, it must be done slowly, to avoid disturbing the layer, which has the consistency of wet toilet paper. Read an earlier post for options on vacuuming to waste, even if you don’t have a multiport valve on your filter. Cartridge filters or filters with Slide Valves don’t normally have this option. Place Multiport valve on Waste, and vacuum to waste, the settled Alum. Turn pump off for 12-24 hours, or until the Alum settles to the pool floor. Put Multiport valve on Recirculate and run pump for 2 hrs Brush pool. Broadcast 4 lbs of Alum over the pool surface, per 10,000 gallons. Balance pool pH, Alkalinity, Calcium, Chlorine and Cyanuric acid levels. Skim, vacuum and brush the pool to remove large debris. Buy Aluminum Sulfate online, or find at a local garden center. HOW TO USE ALUM as a FLOCCULANT in SWIMMING POOLS Alum is considered a flocculant, because it sinks material to the floor – as opposed to clarifiers, which enlarge particles only slightly, for trapping within your pool filter. The tricky part of using alum is that the aluminum hydroxide precipitate must be vacuumed to waste the following day. It works best with well balanced pool water, and in water temperatures of at least 70° F. Eventually it grows to a large size and heavy weight, until it slowly sinks to the pool floor. Over the period of several hours, the alum molecule attracts suspended particles. Particulate matter in solution have negative charges. HOW DOES ALUM WORK in SWIMMING POOLS?Īluminum Sulfate is a double salt with a strong positive charge. And for areas with water restrictions, many pool owners are prohibited from refilling pools from the garden hose, and forced to pay for expensive water delivery. Vinyl and fiberglass pools are not supposed to be drained fully, the liner can relax, or a fiberglass shell can buckle or shift. Whatever the cause, bottles of alum have been absent from pool store shelves (including our own), for over 30 years.Īlum Floc has been making a quiet comeback however, as a quick way to turn around neglected or abandoned pools, without having to drain the water in the pool. Or perhaps it was the now debunked theory in the 60’s and 70’s, of a connection between Alzheimer’s disease and aluminum. 
“Floccing” a swimming pool with aluminum sulfate was a popular way to clear extremely cloudy or swampy pools, up until the creation of polymer pool clarifiers. Its use continues to this day in water treatment facilities, as a flocculant to clear turbid water, and remove phosphates, pathogens and other undesirable particles. By the 16th century, Alum was in widespread use across England, for treating municipal water supplies.
Ancient Egyptian hieroglyphics describe the use of “aluminum earth” and first century Greek and Chinese documents tell of mining and use of alum for clearing water. Aluminum Sulfate, commonly called “Alum”, has been used for thousands of years as a water clarifier.
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