Dear Carlos, we have ...

Dear Carlos, we have conducted verification of sand and our AFM filtration media performance independently by IFTS in France and in our own laboratory. We therefore have definitive data on sand filter and AFM performance.  Filtration performance depends upon, water chemistry, filtration velocity, filter design, sand quality.  There are many factors involved. Also sand becomes biofouled after a few weeks, the biofouling leads to sand coagulation and transient channelling of unfiltered water directly through the filter bed,  So giving a performance for a sand filer is not straightforward.  

A very high quality sand filter will remove approximately 90% of particles down to 10 um, when you use new sand.   Mature sand, can actually work better, but then at set intervals due to bio-dynamic instability it will dump solids back into the water. This may only happen, once a week of once a day for a few minutes,  but it is sufficient to block membranes or cause a disease incident.

Our AFM media  from www.DrydenAqua.com gives a verified performance 10 times better than sand and will remove better than 99% of particles down to 10 um and over 98% at 1 um.  The second advantage is that AFM does not suffer from bio-coagulation and as such it will not allow channelling and passage of unfiltered water through the filter bed.

If you would like more information and  formal reports from an accredited laboratory, then let me know.  Howard@drydenaqua.com