Don’t shoot the messenger, aqua magazine had a big write up on it two years ago I believe. Hayward now will balk on warranty replacement if phosphates are not lower than 500 ppb.
I personally see no reason not to use it, it lowers chlorine demand that can prove excellent should a pool drop lower than the recommended levels.
I might add it’s part of my arsenal now for all my pools. IMO it’s a no brainer. Yes I’ve been converted.
When a salt chlorine generator begins to fail it will not produce sufficient free chlorine to keep up with demand. One possible cause is the presence of phosphates in the pool water.
aquamagazine.com
Yep, I do remember that article and it’s completely devoid of any actual science. They make a conjecture about a chemical reaction without offering any basis in actual chemistry. But let's use their own words against them, shall we -
A product known as zinc orthophosphate is used in drinking water systems because it adheres to metal pipes and acts as an anti-corrosion agent. So, from this we know that orthophosphate likes to cling to metals.
So, from a completely unrelated chemical used in water delivery systems to avoid metallic corrosion, the article makes the conjecture that phosphates "stick to metals". This is a classic if-this/then-that logical fallacy. While it is true that phosphates can be added to water to modify the electrochemical behavior of metal pipes (most notably cast iron and lead solder joints), the chemistry employed there is entirely different than what one finds in an SWG. So this is truly a non-sequitur .
The real interference of phosphates in chlorine generators is still somewhat theoretical. It appears that since orthophosphates attach to metals they attach to the anode and cause an interference with the flow of electrons between the anode and the cathode of the salt chlorine generator. We do know that higher levels of orthophosphate seem to cause a definite interference with the normal operation of the salt chlorine generators.
{emphasis added}
So right there is the crux of their argument, but their argument is totally wrong. Electrons don't flow at all between the cathode and the anode, at least not through the water. They flow along the electrical wiring that connects the anode to the cathode on the external electrical circuit.
Now here's an interesting quote from the comment section made by the author of the article, Terry Arko -
The phenomenon of phosphate interference with salt generators in pools is still relatively new. There really isn't to my knowledge any direct scientific data related to results and exact measurements in swimming pools. The reports and solutions at this point are mainly anecdotal from the field. As with many problems in the pool industry professionals in the field many times are ahead of those in the lab in the observance and solutions to various water quality challenges.
{emphasis added}
So right there the author acknowledges that everything he just wrote in his article is nothing more than conjecture. I give him points for at least being honest there and relating that field testing often is ahead of the industry learning curve (just like TFP and the old Pool Forum linking the FC/CYA ratio to good pool care), but this is case where the anecdotes are saying one thing (high phosphates tend to cause the SWG to not keep up) but the experts have no idea as to what the problem is and are making non-sensical conjecture. Is it possible for phosphate to have some kind of chemical reaction at the anode or cathode? Sure. Does that necessarily imply that the chlorine production will be impeded? Not at all. It is entirely possible for two separate electrochemical reactions to happen with no cross over whatsoever. So again, the experts in this case need to make an argument based on the actual electrochemistry of phosphate (a highly complex molecule to study) and then relate that to what is happening with chlorinated pool water inside the cell. Simply taking concepts from completely unrelated topics and then stating them as fact does nothing to bolster their argument.
It is also always worth reminded people that you need to first vet the source of the information before you put too much reliance on it. AQUA Magazine is a trade-rag that is entirely dependent on subscribers (very small part of it's revenue) and advertisers/corporate backers (the lion's share of it's revenue). Terry Arko is an employee of .... yup ....SeaKlear. SeaKlear makes lots of pool chemicals, not least of which is a line of both residential and commercial phosphate removers. So you gotta ask yourself, "
Do you think there's a conflict of interest there in letting the guy that sells you the chemicals tell you how amazingly important it is that you believe his theories??"
On a personal note, I too use phosphate removers regularly and do believe that phosphate control is good for a pool (it eliminates a variable). But, as I stated above, the vast majority of problems that occur between SWG's and phosphates is not direct-causal, but rather indirect, ie, algae. Phosphates are an algae nutrient and most pool owners take lousy care of their pools. Algae blooms easily overwhelm SWG chlorine production. Therefore, when phosphates are high and pools have algae in them (and yes, clear pool water can have planktonic algae in it), SWG production rates can't keep up and it appears that the cell is not working. SLAM the pool and bring the algae under control and 99.999% of the time the SWG goes right back to being able to maintain chlorine levels.
SeaKlear is the one that is the most concentrated I have found... make sure you are getting the quart bottle and not the pint, sometimes they sell the pint for the same price as the quart so watch out. And you don't have to follow the treatment with clarifier as the instruction indicate... that just gums up your filter even more..
