Trying to decide on which type of filter to buy?

 

There are three main types of swimming pool filters, D.E. (which stands for Diatomaceous Earth) {first filter}, Sand {middle filter} and Cartridge {last filter}. Different regions of the country seem to have different preferences; personally my order would have D.E. first, then Sand, then cartridge filters. However, the suitability of a filter to a pool can have more to do with size, than with type. Always go at least one size larger than you think you need. Buy the largest filter you can afford, it's money well spent.

 

Even though I have just stated a preference of D.E. filters over Sand over Cartridge filters, I would rather have  a large cartridge filter than a small D.E. filter. So remember, in pool filters, size matters! Many filters installed in the 70's and 80's were much too small for the size of pool they filter, and with the deterioration of age are just barely operating. All filters at Poolcenter.com are good, solid technology. Major manufacturers try really hard to produce no "junk." So once again, filter size is more important than brand, name, type, color, etc.

 

Sand filters

 

The sand in a sand filter (#20 silica sand; 45 - 55 mm) is specially graded to trap particles in the 20 - 100 micron range. As a sand filter collects dirt, its efficiency increases, trapping more dirt. When your pressure gauge shows a reading 8 - 10 lbs. over its clean, start-up reading, it is time to backwash the captured dirt out of the filter.

 

"They say" that a sand bed should be replaced after seven years. Gradual loss of efficiency may be hard to notice. If your filter requires frequent backwashing, every week or two, the sand bed may be "mudballed", or it may be "channeled". It may also "calcify" with calcium deposits. Other water balance problems may also contribute to sand deterioration, but a properly sized filter could go over 10 years between sand changes.

 

Use of Biguanide chemicals, i.e., Soft Swim or Baquacil require annual cleaning of the sand to prevent it from "gumming-up". High amounts of bather oils can gum-up a sand bed. And just the years of a pump forcing water over the grains wears away the sharp edges of the sand. Such sand becomes more circular, and traps dirt less efficiently.

 

Remember that for sparkling water, we need the trio of sanitation, filtration and circulation. If one of these areas is lacking, the water won't look so hot. So, if you've kept very good chemical maintenance and your circulation is good, you may have a filter problem. Is the filter sized properly? Many filters of the 70's - 80's were grossly undersized, the trend now in pool filtration is "Go Big Early."

 

Adding a small amount of aluminum sulfate or "alum", through the skimmer will form a gelatinous layer on top of the sand bed, useful in cleaning up an undesirable water condition. You can also add a small amount of D.E. powder or other filter media.

 

"How and When do I Backwash my Sand Filter"

 

When the pressure gauge is reading 8 - 10 lbs above the clean, starting pressure (after backwashing), it is time to backwash the filter. This process involves turning a valve so that the water will flow through the filter backwards, flushing out the dirt. Hence the name "back-washing." Sand filters can have either a push-pull valve (also known as a slide valve) or a multiport valve. The multiport valve has multi-ports on the valve, usually 6 positions:

1. FILTER: Keep it here 99%, except when backwashing, rinsing or wasting

2. RINSE:   Use this setting for 20 seconds after backwashing to rinse tank

3. RECIRCULATE: Use this if the filter's broken; at least you're circulating.

4. BACKWASH: Use this setting to reverse the flow in the filter and send water out of the waste line. Make sure valves are open or hoses rolled out

5. CLOSED: Put here to close off flow from the pool, usually to work on the equipment. Do not operate pump with valve in closed position

6. WASTE/DRAIN: Another filter bypass setting, but this setting sends the water out of the waste pipe (hose), instead of returning it to the pool. This setting is used to lower pool water level or to vacuum to waste.

So, to backwash a sand filter with a multiport valve;

• Shut off pump motor

• Press down on valve handle, rotate valve from FILTER to BACKWASH position

• Roll out any backwash hose or open any waste line valves

• Open air bleeder assembly on filter, and turn pump on.

• Watch pressure gauge for backpressure and hose for kinks. Be prepared to shut off pump quickly

• After hose fills with water, run for 2 - 3 minutes or until water runs clear

• Shut off pump motor and move multiport valve handle to RINSE position Run on rinse for 15 - 25 seconds.

• Shut off pump motor and move multiport valve handle to FILTER position

• Turn pump back on and note lower pressure. Roll up backwash hose

To Backwash a sand filter with a slide valve;

• Shut off pump motor, roll out backwash hose (if you have it)

• Twist to unlock plunger T-handle, pull / twist plunger upwards 2 - 3"

• Open air bleeder assembly on filter, and turn pump on

• Watch pressure gauge for backpressure (+ 40 PSI) and hose for kinks. Be prepared to shut off pump quickly

• After hose fills with water, run for 2 - 3 minutes or until water runs clear

• Shut off pump motor and push T-handle back down into locked position

• Turn pump back on and note lower pressure. Roll up backwash hose

A properly sized sand filter should, in most cases, be able to operate continuously for a period of 4 weeks between backwashings. A "Filter Run" of less than 4 weeks may indicate sand......        (continued........)

Continued I 1 I 2 I 3 I 4 I Next

 

top