Angel Falls Pool and Spa Services
PO BOX 61793
Fort Myers, Fl 33906

Phosphates can cause pool problems.

What are Phosphates? 

Phosphorus is a natural element found in rocks, soils, and organic material. It is used extensively in fertilizer and other chemicals. Phosphates are pollutants that enter the pool water via soaps, detergents, fertilizer, organic debris (leaves, tree bark), fill water, and even from pool chemicals themselves. Once in the water, Phosphates can cause a wide variety of problems as detailed below. In field experience with quite a few CES customers, we have witnessed a terrific pool “go bad” in a short period of time due to elevated Phosphate levels only to recover quickly once the Phosphate level was reduced.

How much Phosphate is TOO MUCH?

This topic has made for some lively discussion in the past few years. Some (phosphate removal) chemical manufacturers have called for removal of all Phosphate above 125 PPB (parts per billion) or 0.125 PPM (parts per million). We find that this might be a bit excessive, and could be expensive to pursue. Our field experience has been that negative effects become more evident once Phosphate levels reach 1,000 PPB or 1 PPM, and that this is when Phosphate removal should be initiated.

A treatment that reduces Phosphates to 300 PPB, or 0.3 PPM is more than enough. Therefore, our recommendation is to treat 1,000 PPM as an absolute maximum, and treat enough to drop the levels to 300 PPB as a normal rule of thumb.

Where do Phosphates come from?

There has been a lot of debate about where phosphates come from. Here are some quick tips:

City fill water: Many municipal water utilities in Florida seem to utilize phosphate treatments that serve to help protect distribution lines against corrosion. Actual concentration of incoming Phosphate can vary from municipality to municipality and even from day to day within a specific municipality. In our experience, Phosphate readings have varied from 500 PPM to a high of 2,500 PPM. The average has been between 500 PPM and 1,200 PPM.  Every time you fill your pool you are adding Phosphates to the pool water. As water evaporates, the Phosphates stay behind, and Phosphate levels continue to elevate due the the additional Phosphate-laden fill water. Over time it is possible for the pool water Phosphate levels to be 4 times higher than the incoming Phosphate readings.

Detergents:  In the 1960’s Phosphates were used to increase cleaning power in detergents and cleaners. The Phosphates in deck and/or tile cleaners sometimes would work its way into the pool water, and cause issues. Over the years, the extensive use of Phosphates caused environment issues in lakes and streams, and their use was reduced in future years. There are even some municipalities that completely ban its use.

Fertilizer & run off: Some of the most dramatic increases in Phosphate levels have come from literally fertilizing your pool water. How so? We have seen a wide variety of problems ranging from sloppy application of fertilizer directly into the pool (great way to stain the surface too), to rain water leaching fertilizer from surrounding lawn or planters into the pool water. We have also traced Phosphate introduction from patrons swimming after walking across a recently fertilized lawn.

Wind blown debris: On several projects we discovered that Phosphates increased exponentially during times of local construction. The pool which had always maintained a high ORP and crystal clear water, became overwhelmed with low ORP, algae, and cloudy water. Once the Phosphate levels were reduced, the pool clarity and chemical consumption quickly returned to normal. We now believe in this phenomenon.

Tri-sodium phosphate: This tried and true filter degreaser is a known source of high levels of phosphates. There are other types of filter degreasers and enzymes that can do the same job, with less impact on Phosphate levels.

Scale & Stain Prevention products: Sequestering agents are used to prevent the precipitation of heavy metal salts (Iron, Copper, Manganese, etc.) from pool water. They are very valuable tools in the overall operation of pools. Many of them, however, contain either orthophosphates (the chemical we are trying to remove, or polyphosphates (which eventually might convert into orthophosphates in the chlorinated pool environment). Still, stain prevention is so important that an occasional Phosphate removal procedure might still be warranted as a necessary correction to this predictable phosphate increaser.

Does a presence of Phosphates mean that you will have algae?:

No! Maintaining a consistent ORP > 700 mV, and keeping your entire circulation and filtration system in peak working order will normally go a long way in preventing algae breakouts. Keeping Phosphates below 1,000 can only help the process.

Known issues resulting from high Phosphate levels:

BulletAlgae: Growing algae requires sunlight, carbon dioxide, and several key growth nutrients (nitrogen, phosphorous, and sulphur). Research shows that controlling Phosphate levels can directly limit algae growth. In CES field studies, Phosphate levels above 2,500 PPB (2.5 PPM) significantly increased chances of growing green algae. Phosphate levels alone are not the culprit, as low chlorine levels, excessive chlorine demand, high cyanuric acid levels, and poor filtration will also help grow algae.

BulletCloudy Water: In certain circumstances, high Phosphate levels has been blamed for cloudy pool water. Upon closer examination, one will probably find that the cloudy water was probably caused by low sanitizer levels and/or poor oxidation.

BulletSuppressed ORP: Research shows that higher levels of Phosphates will attract Hydrogen, and will effectively help suppress ORP. Field observations have supported this as we have experienced ORP increase after successful Phosphate removal treatments.

BulletReduced output from Saline Chlorinators: Some feel that high Phosphate levels can lead to fouling of the saline chlorinator titanium cells, thus reducing the output. Since saline chlorinators “trickle-feed” chlorine into the pool, any suppression of ORP also could result in sluggish Saline Chlorinator performance. We have witnessed reduced output in high Phosphate pools, and have successfully treated using a combination of technologies. Contact your CES rep for more information.

BulletReduced life of Saline cells: The exotic coating on saline cells have a finite life span which could be expressed in number of hours of operation. If your cell is not connected to an ORP control system, or has to run longer due to ORP suppression, it may well result in a shorter cell lifespan.

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