Tuesday, May 23, 2017

How Can I Tell How Much Filter Media I Need To Rebuild My Filter Tank?


Looking to purchase coconut carbon material and support gravel for a
residential style whole house filter. Not sure what type and quantity?  How
can I tell how much filter media is needed to rebuild my existing filter

I use a carbon filter with a backwash valve on top, to keep my house water
clean. It has been in for some years and I know I need to change the
charcoal inside it.

I saw on your website that there are two different types of coconut shell
carbon.   You showed something called "catalytic carbon", and it was more
expensive.  Which is better?

Paducah, Kentucky

Hi Donald,

Your tank’s dimensions will “tell” you how much.  The number should be
written on the tank at the bottom; it goes diameter by height.

Most residential filter tanks are sized by the cubic foot size of the filter

For example a 9" wide (the diameter) by 48" tall (the height of just the
tank itself, without the backwash control on top).

844 = 0.75 Cubic Foot
948 = 1.0 Cubic Foot
1054 = 1.5 Cubic Foot
1252 = 2.0 Cubic Foot
1354 = 2.5 Cubic Foot

In a typical backwashing carbon filter system, the filter tank is filled 2/3rds of the way from the bottom with filter media.  The free space at the top gives some room for the filter media to expand during backwash.

The water flows in through the top of the tank and down through the carbon filter media.
At the bottom of the tank is a bed of filter gravel and the distributor tube
and bottom basket strainer.

Water flows down through the media and then up through the distributor tube and out to the house clean and filtered.  After some period of days (often once a week or perhaps every two weeks at most) the automatic backwash control valve turns on automatically and begins a backwash and rinse

During the backwash, the water flows down through the distributor tube and reverse flows up through the carbon filter media and out to drain.  The carbon is cleaned and rinsed and the carbon bed is "re-classified" meaning the particles are re-distributed.

This helps the filter media last a little longer and can help prevent odors from developing in the carbon, as fresh chlorinated water from the city cleans the carbon.

The backwashing won't remove chlorine or other chemicals that have adsorbed into the carbon pores, but it does wash out accumulated sediment.
Backwash carbon filters generally do work better than non-backwashing types in our

How much filter gravel to add?

It is best if the gravel is about 2" to 3" above the top of the bottom
strainer.  Here is a typical amount of gravel in pounds used for the common
tank sizes:

844 = 10 lbs.
948 = 12 lbs.
1054 = 16 lbs.
1252 = 20 lbs.
1354 = 35 lbs.

Activated Carbon

Activated Carbon Coconut Shell 12 x 30 0.5 Cu. Ft. Coconut shell carbon, because it is comprised of predominantly microporous structures, is a superior performing product for the removal of chlorine, chlorinated solvents, and VOCs. It is also harder and can stand up to more backwashing than bituminous coal based carbon. Its drawbacks lie in its higher price and its inability to absorb heavier organics. 12 x 30 Mesh

What Type of Activated Carbon To Use?

Activated carbon is sometimes referred to a charcoal, but actually, it is
manufactured under very high pressure and heat from various forms of
charcoal.   To remove chlorine and tastes in city water or chlorinated well
water we recommend coconut shell carbon.

Coconut shell carbon, because it is comprised of predominantly microporous
structures, is a superior performing product for the removal of chlorine,
chlorinated solvents, and VOCs. It is also harder and can stand up to more
backwashing than bituminous coal based carbon.    Coal based carbon, made
from anthracite coal is also used sometimes, but generally, coconut shell
works better.

Catalytic Carbon refers to activated carbon that is coated with a
nitrogen-based coating.  Catalytic carbons is a type of high activity
granular activated carbon manufactured by steam activation of select coconut
shell charcoal.

Catalytic means that chemical reactions can happen on the carbon, without
the carbon itself being consumed.  Catalytic carbon is especially used for
the removal of chloramines (city water that has been treated with both
chlorine and ammonia).  It also works great to remove hydrogen sulfide
(rotten egg odor) in well water, usually after the water has been aerated

The catalytic activity of this type of activated carbon makes it highly
effective for the removal of chloramines and hydrogen sulfide from potable

Its large micropore volume makes it particularly well suited for the
removal of low molecular weight organic compounds and their chlorinated
by-products such as chloroform and other trihalomethanes (THMs).

Carbon Backwash Filters

Remove Chlorine & Chloramine, Tastes & Odors For The Whole House


Excellent for use in dechlorinating water and removing tastes and odors

Removes chloramines with the optional Catalytic Carbon upgrade

Much longer life and higher flow rates than carbon filter cartridges.

Unlike carbon cartridges which can trap sediment and dirt, these systems automatically backwash out trapped sediment, alleviating pressure drop.

NSF certified, one piece, seamless polyester filter tank for long life

Backwash control valve has fully adjustable backwash and rinse cycles to save water and allow maximized performance

User-friendly LCD, displaying time of day, regeneration mode, and gallons remaining before backwash

Totalizer function, tracking total amount of water treated

Meter immediate, meter delayed, meter with day override, and calendar clock regeneration modes available (See manual for details)