Phosphates in Hot Tubs: Causes and How to Lower / Remove
Water can be complicated and lots of factors come into play when balancing and ensuring hot tub water is safe. One aspect that can go under the radar is the phosphate level. This is by no means a 'core' level like sanitiser (chlorine or bromine) or PH/Alkalinity however it can have an impact on these levels and in specific cases it can cause headaches when trying to get things balanced. In this blog post we will explain what phosphates are, what causes the level to get so high in hot tubs, the impact of high phosphates and how to remove phosphates from your water.
What Are Phosphates?
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. Phosphates can be found in almost everything from food, water and in our bodies. They are not visible and are in quite low concentration (highlighted by that phosphates tend to be tested in parts per billion rather than parts per million).
What Causes High Phosphates in Hot Tubs?
Phosphates can enter your hot tub from your source water on initial fill. The phosphate level will be then added to from multiple sources including rain water, leaves, body oils, cosmetic products and even some hot tub chemicals. So you could well have a high phosphate level in your hot tub straight after fresh fill and also add them when topping up from your garden hose.
What Problems do High Phosphates Cause to Hot Tub Water?
Phosphates will not directly cause harm to a bather in a hot tub however they can have an impact on sanitiser demand and therefore reduce sanitiser level significantly, which in turn could make a hot tub unsafe. Phosphates are the main food source for algae growth in water. This means that high phosphates levels give algae the perfect opportunity to grow. To fight algae growth you will have a sanitiser present in your water (chlorine or bromine), however if algae is feeding off of high phosphate levels then you will find yourself using more and more sanitiser to counteract this.
Phosphates in Salt Water Hot Tubs
The problem of phosphates tends to be exacerbated in salt water hot tubs. The reason for this is because Salt Water systems like the Hot Spring Freshwater Salt System are designed to deliver the optimium level of sanitiser to keep water clean. If excess sanitiser demand is created by things like dirty filters, increased bather load or high phosphate levels then the system does not perform as expected. A salt system cannot 'shock dose', it can only be turned 'on' for longer and therefore if sanitiser is being used up fighting high phosphates/algae then it really struggles to produce enough sanitiser to meet the demand. Removing or reducing phosphates levels in the spa allows the salt system to perform more efficiently.
How to Get Rid of or Lower Phosphate Levels in Hot Tubs
It is highly unlikely that you will remove all of the phosphates that are present in hot tub water however reducing the level will have a positive impact on sanitiser efficiency. The good news is that thanks to AquaPro Phosphate Remover the removal of phosphates is pretty easy. You simply need to ensure your filter is cleaned prior to dosing and then add the relevant dose of the phosphate remover to the water (see the Directions for Use tab on the product page for further information).
FAQs
What level should phosphates be in a hot tub?
Keep phosphates below 300ppb to avoid problems in your pool or hot tub.
How do you test for phosphates in your hot tub?
We reccomend using the La Motte Insta Phosphate Test Strips.
