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Drop of Hope - Follow up

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Follow up with the user - Is your BioSand Filter working well?

What Will Tell Me If a Filter is Working Well?

There are 8 points that can tell you if a filter is treating water well. They are called the 8 Key Filter Performance Points. If these 8 points are met, you can be confident that the filter is removing most microbiological contaminants.

1. The filter was installed more than 30 days ago.

It takes 30 days for the biolayer to grow and be working well.

2. The filter is used at least once every day, with water from the same source every time.

Don't forget the Pause Period: after the water stops running, you must wait at least 1 hour before filling it again.

3. The water poured into the BSF is clear.

If you only have dirty or cloudy water, leave it in a bucket until the sediment has settled to the bottom. Then pour the clear water in the bucket into the BSF. Do not pour the sediment in.

4. The filter container does not have cracks and is not leaking.

Users may not use filters that don't look nice or that make a mess. Also, a leak may cause the standing water level to be too shallow, and the biolayer may be damaged.

5. There is a diffuser.

It should be in good condition, so the biolayer is protected when you pour the water in. There should be no cracks or large holes in the diffuser.

6. When the water stops running, the water surface is 5cm (2") above the top of the sand.

If you don't have a ruler with you, 5 cm is about the length of your middle finger from the tip to the second knuckle. It is ok if the water depth is between 4 to 6 cm (1.5-2.5").

7. The top of the sand is flat and level.

If there are dents, holes or "valleys" in the sand, the biolayer may be damaged

8. When the filter is full, the flow rate is 400 mL or less per minute.

If you get more than 400 mL in1 minute, the filter may not be operating at its highest possible treatment efficiency.