Tank Water Filtration
All tank water used for human consumption should be filtered. Tank water quite often becomes contaminated by animals, animal faeces, dirt, leaves and algae.
None of these things are entirely pleasant commodities to have in your drinking water, hence the need for filtration.
What is the standard type of filtration used for tank water?
There are several different applications for tank water filtration.
When the tank is new or freshly cleaned you should look at a single or a twin system with a 5 micron poly spun sediment cartridge.
When the tank is older and/or has a fair amount of build up, you should definitely select the 20" x 4.5" twin system with a pleated 20 micron sediment filter first, followed by a 5 micron poly spun sediment filter. The pleated cartridge has a larger surface area and can be cleaned to some degree and re-used. This will protect the poly spun cartridge (which is a disposable cartridge) and offers finer filtering (down to 5 mic) than the 20 mic pleated cartridge.
The only exception to the above would be if there is any taste issues or organic smell to the water that you're not satisfied with. If there is taste or smell in the water you should use the same system but set the cartridges up with a poly spun first followed by a carbon cartridge for taste and smell reduction.
My tank water is discoloured:
Discolouration is a common problem and is often caused by leaf matter in the gutters or in the tank itself. If you are experiencing any colour issues (tannins) you should again opt for the twin 20" x 4.5" system with the poly spun sediment and carbon cartridge to absorb the colour, both at 5 micron.
Unfortunately this may not always be successful. Tannin is the single hardest problem to correct in tank water. Due to the various type of trees and the oils that they leach, filtration may or may not be successful - it is simply a trial and error basis. The real solution is a chain saw to get rid of the trees surrounding the tank!
My tank water is extremely dirty:
If you have very dirty water or a stagnant smell , the first thing you need to consider is having the tank commercially cleaned. There are companies now that can clean your tanks out with minimal water wasted.
After the tank has been cleaned, you should consider using a sanitizer (check out the info on our preferred sanitizer: HydraSil) HydraSil is a peroxide based and silver stabilised, odourless, all natural sanitiser. If you still don't have filtration you should once again choose the 20" x 4.5" twin system with 5 Micron poly spun sediment and or carbon pending other conditions listed above.
Do I need a 10” or a 20” system?
We always suggest 20" systems for water tanks, although both the 10" and 20" systems offer the same flow rate with the 1" ports, the contact time in the 20" system is much longer - offering better extraction of colour and smell issues. Buying the 10" systems could be considered false economics. The cartridges expire quicker, you have less contact time (particularly with the carbon), more frequent changes and cleans, and you have your hand in your pocket more often that you need to. Our advice unless you have a 1 bedroom cottage is to stay with the 20" x 4.5" Big Blue systems.
Will I need a pressure pump if I install a filter ?
The answer is yes - unless you have a decent head of pressure on your gravity feed, and even then you may still need a pump once the filters begin to fill.
How much pressure will I need to filter my water?
The absolute minimum pressure required will be about 25 psi (172.38 Kpa) The ideal pressure to run filtration would be from 40 psi - 70 psi , most pressure pump system allow for adjustments to pressure, or consult your pump supplier for advice.
What flow rate would I expect from a 10" or 20" x 4.5" Big Blue filter system?
This will depend on what cartridges you run, however the 10" x 4.5” and 20" x 4.5” (both with 1" ports) will offer flow rate in excess of 90 Ltrs/Min with just a sediment cartridge.
If you are running a carbon filter this may drop off to 40-50 Ltrs/Min , as will the efficiency of the carbon at these flow rates.
Optimal flow rate for these carbon blocks is 30 Ltrs/Min. The carbon's performance will peak at about 35 Ltrs/Min, after this the carbon becomes less effective on colour extraction and taste issues. To put this in perspective a general house with two bathrooms will consume up to 45 Ltrs/Min.
Will I place the filter before or after the pump?
All filtration must be fitted after the pump. Filter vessels are pressure vessels, not vacuums.They need the pressure produced by the pump to function correctly. If you place a filter before the pump it will work fine until it begins to block, but once it blocks it will limit the flow of water getting through it. At this stage you run the risk of collapsing the housing or burning the pump out or both.
Always install filtration after the pump.