There is more to think about than just calcium when it comes to scale in your swimming pool. Scale can be visibly seen in the pool, as well as feel rough to the touch when it appears on pool surfaces, fixtures, plumbing, and even inside of your equipment.
The most obvious cause of scale is often calcium. Especially in salt water pools where there needs to be a zinc anode to handle the effects of electrolysis – we often see calcium deposits form when the anode is missing. Another cause to look to for scale in pools is phosphates. The drinking water industry indicates that excessive phosphates may form a phosphate scale, typically when the concentration of phosphates exceeds 2000 ppb. In pools with high phosphate levels the scale can be stronger than average if the calcium has combined with the phosphates to form the resulting scale. This scale may require scraping as well as an acid wash to be removed from pool surfaces. Take care not to damage pool surfaces while removing the scale.
Phosphates in pool water
Phosphates are common in pools, though most homeowners may ignore this and never even think about phosphates in their pool. Phosphates are inorganic chemicals that are a primary food source for all types of algae.
Phosphates are compounds of the nonmetallic element phosphorous and are a primary food source for aquatic plants, including all types of algae. Phosphate compounds are inevitably broken down into their simplest form, orthophosphates, in one of the following three ways:
- Oxidation (converting compounds into oxides)
- Hydrolysis (decomposition by water)
- Enzymatic digestion
Regardless of how it happens, if phosphates are allowed to remain present in pool, spa, or pond water, they will be reduced to orthophosphates, which are the only form of phosphates that algae can digest. Orthophosphate levels should remain below 100-125 ppb (parts per billion). Once levels exceed 200 ppb, algae becomes increasingly resistant to sanitizers, including chlorine shock. Excessive levels of orthophosphate, such as 1,000 ppb or more, should be brought under control with Natural Chemistry phosfree Commercial strength .
Sources of Phosphates
Phosphates can be introduced to the pool by:
- Wind blowing dirt into your pool
- Sprinkler run off from lawn or landscaping
- Water leveler adding fresh water into the pool
- leaves/twigs and bark entering the water
- using chemicals containing TSP or any phosphoric based ingredients to clean your pool
Controlling Phosphate Levels
You will always have some level of phosphates in your pool water. It’s best to maintain a “near zero” level through the use of products such as Natural Chemistry’s Phos Free to keep the level controlled. You can use preventative pool maintenance to limit phosphate exposure by:
- Removing leaves and organic material from the water as soon as possible.
- Vacuum and clean your filters and pump basket regularly
- Don’t allow drainage from landscaping to flow back into the pool
Prevent Calcium Phosphate Scale
- Remove phosphates when they become a problem
- Reduce the ability of calcium and phosphates to come out of suspension *only in extreme circumstances
- Keep your water in balance
Something to note: removing phosphates will not kill algae. If you have algae, in addition to removing phosphates you’ll need to shock or superchlorinate your water to kill the existing algae in your swimming pool.
Recommended Natural Chemistry Products
Natural Chemistry PhosFree
Natural Chemistry Phosfree brings phosphate levels to near zero and should be used when you first begin your phosphate management program. phosfree is non-toxic and will not cloud pool water. It is added directly to the skimmer and is compatible with all types of swimming pools, filters, and sanitizers.
Pool Perfect plus PhosFree
Natural Chemistry Pool Perfect + Phosfree is a weekly maintenance product that continually removes phosphates and organic contaminants from pool water. Pool Perfect is a powerful enzyme that reduces the need for maintenance by breaking down organic contaminants, surface oils and prevents scum lines. It continually cleans the filter media and makes water feel noticeably softer.
Pool Magic plus PhosFree
Natural Chemistry Pool Magic + Phosfree is perfect for use when opening or closing your swimming pool. Pool Magic uses enzymes to break down organic contaminants and prevent organic staining while the pool is closed for the season. It likewise brings them under control after the pool is opened.