JasonLion said:
The filter thing doesn't make any sense to me. DE filters are the worst possible kind of filter for an area with especially large amounts of silt.
It's the
size of the silt. Okay, so I really should be calling it chalk and clay particles to be more exact. I throw all of that fine stuff into the category as silt as opposed to clay (smaller particle sizes) or sand (larger particle sizes). Some of our silt [sic] is finer than 1 micron.
I haven't officially measured it yet and I forgot to pick up some scaled slides my Vet ordered for me. Will do so next visit in two weeks. In my reading tonight I found out that we
do also have a lot of clay in our soils but here in the woods we have a lot of loamy soil from the tree decomposition; much more so than other areas around here, away from the woods.
According to Wikipedia
Loam is soil composed of sand, silt, and clay in relatively even concentration (about 40-40-20% concentration respectively), considered ideal for gardening and agricultural uses. Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils.
Not everyone has the quantity of silt we have here but the size is pretty common up here on the Austin Chalk Escarpment. As you know cartridge and sand filters don't filter down as fine as DE. It's simply that in particular that makes the DE filter a necessity out this way.
There is one additional factor that I don't really like to even think about. It's been a controversial environmental issue for years out here. Hopefully our hundreds of acres of trees in protected lands, habitats, parks, suburban areas help to improve the quality of the air. About 7 miles south of us is Midlothian. Midlothian is a prime area for cement quarrying due to the Austin
Chalk Escarpment, a unique geological formation that runs north-south through the region. Three of the top ten largest cement factories in the United States operate in the city. We sit right on top of that Austin chalk. A unique characteristic is that the fertile soil, but mostly rock, has chalky rocks constantly working up to the surface and then disintegrating by wind and water very rapidly. My soil, here at the very top, is almost 90% rock/10% soil. A lot of the sand is brought in for construction of houses/buildings/roads/pools, etc. but much is also blown in from the west with prairie just a few miles from us. We are also sitting on top of one of the largest gas shale deposits in the US. Lots of horizontal wells are going in now days all around us. They do drill very deep going vertically before they go horizontal but the drilling puts even more fine "stuff" into the air. My town has been developing rapidly in past 15 years with huge population growth=development and disturbing of virgin forest and grazing/farming lands and it is becoming one of the largest shopping areas in the DFW metroplex. So chalk in the air has been increasing exponentially the past few years. The dust in my house, even when tightly closed up with multiple filtration systems, has many of the properties of DE including sapping the moisture out of skin on contact and keeping the bug population down without using chemicals. Asthma is pretty rampant in school age children probably from the chalk "silt". Luckily we have a few months out of the year that the winds don't blow from the south. Most of our "pollution" is not dark brown or black like you find in urban areas rather it is light tan to white. Not much of the Dallas pollution settles out this way as it is blown away before settling, thank goodness.
Hope this helps to shed some light on our very unique needs for water (and air) filtering.
Our chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. We don't get acid rain with all the chalk in the air. Not joking either. Our current water supply is surprisingly low in calcium but until about 10 years ago it was extremely high making pH management in the pool extremely difficult.
From Wikipedia
http://en.wikipedia.org/wiki/Silt
It is in semi-arid environments [6] that substantial quantities of silt are produced. Silt is sometimes known as 'rock flour' or 'stone dust',..............Sedimentary rock composed mainly of silt is known as siltstone.
Silt is easily transported in water or other liquids and is fine enough to be carried long distances by air in the form of dust .... Silt and clay contribute to turbidity in water
In the Udden-Wentworth scale (due to Krumbein), silt particles range between 1â„256 and 1â„16 mm (3.9 to 62.5 μm), larger than clay but smaller than a sand. ISO 14688 grades silts between 0.002 mm and 0.063 mm, with clay particles being smaller and sands larger. [ 1 micron = 0.001 mm so I'm, in acuallity, talking about fine clay particles when I describe our smallest size "silt"] In actuality, silt is chemically distinct from clay, and unlike clay, grains of silt are approximately the same size in all dimensions; furthermore, their size ranges overlap. Clays are formed from thin plate-shaped particles held together by electrostatic forces, so present a cohesion.
According to the USDA Soil Texture Classification system, the sand-silt distinction is made at the 0.05 mm particle size.[7] The USDA system has been adopted by the Food and Agriculture Organization (FAO). In the Unified Soil Classification System (USCS) and the AASHTO Soil Classification system, the sand-silt distinction is made at the 0.075 mm particle size (i.e. material passing the #200 sieve). Silts and clays are distinguished by their plasticity.
A main source of silt in urban rivers is disturbance of soil by construction activity. [/i]
gg=alice
Debris was so bad she even had to use the leaf net. She didn't tell me that but there were tell-tell signs.