Fluoride Reduction
Removing fluoride from water can be a tricky thing to do.
The best and effective methods are as follows:
#1 Reverse Osmosis (RO): Removes up to 85-97% of fluoride alongside other heavy metals. It’s one of the most effective ways to reduce fluoride at the tap.
#2 Water distilling: The steam is then condensed back into liquid, producing purified water with significantly reduced fluoride and other minerals, heavy metals, and most contaminants.
#3 Activated alumina filters
An NSF 61-certified granular activated alumina (AA) is a specialised filter media designed to effectively remove fluoride and arsenic from drinking water. Made from aluminum oxide, AA has an exceptionally high surface area, which allows it to adsorb fluoride efficiently. In municipal water supplies, fluoride concentrations are typically around 2 ppm, and AA filters can reduce this to below 0.1 ppm.
Drinking water only
Undersink designated drinking water dual water filtration with a low flow tap will provide the best results effctively removing up to 95% of fluoride when it is new. The second filter (CTO 1 micron carbon block filter ) will help to improve the water quality and prevent any taste issues.
Whole house filtration
Best results rely on the fluoride to have as much contact time with the filter media as possible allowing the fluoride to be bonded to the highly absorbant Activated Alumina media. Example if the flowrate passing through is high due to the amount of taps running at one time the fluoride reduction rates are significantly reduced. A single flowing tap under 10lpm will provide the best reduction rates.
How water PH Levels impact Activated Alumina (AAL)
The best pH level for activated alumina to effectively remove fluoride from water is between 5.5 and 6.5.
Here’s why this pH range matters:
- Higher Fluoride Adsorption: The slightly acidic environment enhances the fluoride-binding ability of activated alumina.
- Lower Effectiveness at High pH: At higher pH levels (above 7.0), fluoride removal efficiency decreases significantly because fluoride ions are less likely to bind to the alumina surface.
Examples:
- pH 7.5:Efficiency might drop to about 30-50%.
- pH 5.5-6.5: Efficiency can reach 85% or higher.
Summary:
There is no definitive time frame for when a AAL fluoride filter should be replaced, nor a guaranteed lifespan. If unsure periodic water testing or filter replacement based on usage are recommended but often not feasible.
How much water do you use?
What is your PH level?
Having a good quality variable density sediment filter and a 1-micron Matrikx carbon filter before the activated alumina (AA) filter can significantly extend the lifespan of the AA media by 30-50% although it doesn't directly affect its fluoride adsorption capacity.
Here's why:Prefiltration in whole house sytems prolong the lifespan of the AAL media.
- Preventing clogging from debris.
- Reducing fouling by organics, chlorine, or heavy metals.
