SACRIFICAL ZINC ANODES FOR SALT WATER POOLS
How it Works
The Sacrificial zinc anode protects all metal parts (heaters, lights, rails, etc.) from galvanic corrosion. Zinc anodes will sacrifice themselves and corrode before all other metals in the pool. Zinc anodes need to be replaced approximately every 4-5 years.
Reasons for using Zinc Anodes in chlorine-generated salt water pools
Any time you have different metals (copper, stainless steel, etc.) in a salt water pool, you create a battery. Some amount of current flows between the metals. The electrons that make up the current are supplied by one of the metals, giving up bits of itself in the form of metal ions to the pool water. This is called galvanic corrosion. Galvanic corrosion causes plaster discoloration and metal erosion. The best way to inhibit the effect of galvanic corrosion is to use a zinc anode. Zinc is a metal that gives up its metal ions faster than other metals in the pool. In other words, the zinc anode will erode instead of other metals (pool light, rails, heater, light niche, ladder, etc.). The zinc ions will not discolor the pool plaster. The zinc anode should be replaced after half of it has eroded.
Salt systems. We have received many questions regarding the use of alternative chlorine generation systems, referred to as "Salt Systems".To help answer them all we have listed some details below;
Do I have to add salt every month with a salt water chlorinator?
Salt should be added to the pool when necessary. Salt level may decrease after a heavy rain, backwashing, refilling, draining or excessive splash out.
Do I still need to use granular chlorine with my Salt water chlorinator?
The salt water chlorinator replaces the hassle of having to use granular chlorine. If the chlorinator is the correct size, then it's sufficient to sanitize the pool without adding granular chlorine.
How do I add salt?
Is it true that a salt water chlorinator provides chlorine-free water?
No, a pool treated by salt water chlorination is a chlorinated pool in which the chlorine is produced automatically. The salt under the effect of electrolysis, is transformed into sodium hypochlorite, a disinfectant.
Is it true that salt water chlorination is maintenance free?
While the salt water chlorinator prevents the user from needing to add chlorine to the pool on a regular basis, some maintenance, in regards to water balancing, will still need to be accomplished.
Check the water balance as usual. The water balance will be less threatened, because only pure chlorine is added to the water. All other forms of chlorine (tablets, powder, liquid, etc.) contain additives. In addition, chlorine levels can be stabilized easier with less dramatic fluctuations.
My pool is currently treated using bromide. Can I switch from bromide to salt water chlorination using the same water?
If there is still a large amount of bromide in your pool, we recommend that you wait for it to dissipate. It is ok to startup the chlorinator when there is a little bromide in the pool.
The remaining bromide in the pool will produce a white emulsion (chemical reaction). The remaining bromide will not harm the users, pool equipment or the pool.
What is polarity inversion on a salt water chlorinator?
Polarity Inversion is what salt water chlorinators use to periodically remove scale from the electrode plates. The controller will periodically change the direction of the cell current in order to eliminate the layers of scale that deposit on the electrode plates. This action maintains the cell. For very hard water, some chlorinators can shorten the polarity inversion time (e.g. 2.5 hours instead of 5 hours) so that the electrodes are cleaned more often.
Warning: shortening the polarity inversion time can wear the electrodes more than usual. This is why changing this parameter is reserved for the pool professional.
What type of salt needs to be used for salt water chlorination?
Salt only needs to be added when necessary. This may be necessary after heavy rains, backwashing and refilling, excessive splash out, etc. It's always important to test the salinity before adding salt to determine how much salt should be added.
Will salt from the salt water chlorinator deteriorate the metal components in my pool?
If the ladder is bonded properly to the rest of the pool equipment, corrosion will be minimal. Most cases of corrosion can be better explained by an incorrect water chemistry as opposed to the presence of salt.
Stainless steel is better adapted to resist salt than Galvanised steel. If corrosion appears in one year, it can be explained by incorrect water chemistry or bonding issue, not by the presence of salt alone.
Will there be any harm if someone swallows salt water in a salt chlorinated pool?
While the salt shouldn't have any effect on the person if a small amount is swallowed, please keep in mind that the water is chlorinated and chlorine should not be consumed.
Salt system shows low salt but we had it tested and it is okay, the pool store tells us we need a complete new salt system.
Salt system control units will give a reasonably accurate reading for the salt content in the pool, with one exception, when the cell has expired. You did the right thing in having the salt tested independently. Your service tech can test your salt for you and should be doing so as a matter of course every 3-4 months just to make sure the system is reading correctly and there are no other issues.
Many homeowners, when purchasing salt systems for the first time, are not informed of all the relevant information on the life of the systems. Do not presume that once you buy the system and have it installed it will operate tirelessly for the life of the pool. If we use the Hayward Aqua-Rite or Pro-Logic systems as an example, the cells used on these systems have an operating life of 10,000 hours. After that the life of the cell expires and the cell requires to be replaced in order to continue to produce chlorine. If the clients pool runs for 9 hours per day 7 days per week the cell will be required to be replaced in 3 years and 3 months.
A replacement cell for the Hayward system can cost up to $650 for another cell that will only last another 10,000 hours. Several manufacturers have developed aftermarket replacement cells that directly retrofits into the Hayward unions. They are cheaper than the Hayward AND they have a stated life of 15,000 hours, coupled with the fact that the cell itself is see through and the warranty is 3 times better than that of the Hayward, it appears to be a "no brainer", however, buyer beware, several companies that produce these aftermarket cells including Compupool have gone out of business, therefore so has any warranty
Personally, I would replace the system with the latest technology from JANDY.
Jandy use proven technology to ensure that their units do not suffer from board failure with the slightest surge, a common complaint with the Hayward systems.
It is a common misconception that excessive Chlorine causes the burning sensation on your eyes. "Eye Burning" is usually the result of too little chlorine in the pool water or an incorrect pH balance.
Have the water tested by a professional who will be able to test and distinquish the levels of Free Available Chlorine and Total (often called Combined) Chlorine. The golden rule is that these two results ideally require to be close to each other, for example, if you have a free level of 2.3ppm and a total or combined level of 2.8ppm then you are in good shape, however, if you have that free of 2.3ppm and a combined of 3.4 then your pool is loaded with Chloramines which are a nitrogen compound and will cause eye irritation. The most common Chloramines are NHCI and NCI these Chlormaines are present from rain, perspiration and urine among other things. The way to reduce the deficit between the two readings is to superchlorinate or shock the pool, this will burn off the Chloramines and bring the combined levels down to equal the free levels which in turn will mean that your pool is full of free available chlorine ready to act as a sanitizer. Check the pH level as this can also be effected by heavy rain as it causes an inbalance in the Alkalinity which in turn allows the pH to "bounce".
The introduction of foreign matter coupled with pool filter operation may cause cloudy water (algae may also cause cloudy water). Check the filter run pressure, if it is over 10psi higher than the start-up pressure after cleaning then the filter is not operating effectively and needs to be assessed for either cleaning or element replacement.
A high pH level can also be attributed to the cause of cloudy water. Your pH should be checked and adjusted weekly as part of your general pool maintenance.
Another factor which can cause cloudy water is poor circulation or low filtration times. Some filters/pumps require to be be run continuously, such as above ground pools. Some pool owners are reluctant to do this and mistakenly blame the lack or excess of chlorine for the cloudiness.
Poor circulation occurs most frequently when the main drain is turned of and the pool is run purely on skimmer filtration. The skimmer circulates only the surface water which results in a build-up of contaminants in the deep water of the pool. Main drains should always be in operation except when using an automatic pool cleaner through its own suction outlet, if using a pool cleaner through the skimmer, the main drain must be open for suction.
Having your pool re-finished is not only a big undertaking but also a considerable financial investment. The first month of pool service is the single most important phase of any re-finish.
I would strongly recommend you contract with a certified, licensed and insured pool service company for that 1st months service. Average cost for the first month pool service following a re-finish is $385. This involves 6 daily visits per week for the complete month to monitor the pH, Chlorine and Alkalinity levels, daily sweeping and vacumming as required with a brush vacuum only, filter cleaning as and when required which could be as much as every 3 days, balancing Cyanuric acid level at week 3, maintaining checks on Calcium hardness levels throughout the month and balancing the pool for swimming during week 4.
If you value the investment in your new pool finish contract with a service professional, take on this 1st months service yourself and you risk damage to your new pool finish.
Alkalinity is probalby the easiest test measurement to correct in relation to your swimming pool. Your Alkalinity will be effected greatly by any rain. It is very unusual to have a neutral rain so it will either be a base or acid. Either way it will tend to lower or raise the Alkalinity. If the change in Alkalinity is caught early enough it will not be allowed to effect any other perameters, however, any change in Alkalinity which removes it from it's balanced range of 90-110 ppm will allow the pH measurement to go into a state classed as "pH bounce" which effectively means the pH will increase or decrease at will until it is stabilized along with the Alkalinity.
In effect the Alkalinity is a set of handcuffs which stabilize the pH.
To raise Alkalinity add Sodium Bicarbonate directly to the deep end of the pool, it is not necessary to have the filtration system running. 1.5lbs of Sodium Bicarbonate will raise the Alkalinity by 10 ppm in a 10,000 gallon pool.
Additions of large amounts of Sodium Bicarbonate can temporarily cloud the pool but this cloudiness will generally disipate within a few hours.
High pH can cause extensive scaling and damage to the pool interior finish if not correctly balanced on a weekly basis. The acceptable range for pH is 7.2 - 7.8 but the optimum comfort level for pH would be 7.4 as this is the closest point to the pH level of human teardrops at 7.35.
Ph will fluctuate naturally especially if the Alkalinity is out of range.
High pH can be reduced by the addition of Hydrochloric Acid, commonly referred to as Muriatic Acid. Hydrochloric Acid adds hydrogen ions H+ to the pool water thereby reducing the pH range of that body of water.
Problems with Algae seem to be compounded in hot weather climates and after heavy rains. Algae appears to more prevalant during the transition from summer to winter and winter to summer. Algae causes water to become green and cause slippery growth on ladders, sides and the bottom of the pool. Black algae growth shows up intially as small black spots and are harder to remove than green or mustard (yellow) algae.
Green and yellow algae can be removed by super chlorination followed immediatly by brushing the pool walls and floor, vacuuming is recommended 2-4 hours later and then filter cleaning 24 hours later is a must to remove the algae spores from the flter elements. If you fail to clean the filter your algae will return.
To remove Black Algae it is advisable to use a product that is specifically designed for this purpose. The successful removal of Black Algae requires high free chlorine leves to be maintained over anextensive period of 3 -5 weeks and sometimes even longer.
In the winter months your pool can be kept free of algae by making sure you have a chlorine residual (free chlorine that is available to be used as a sanitizer) of 1 - 1.5ppm. In summer months increase that to 2.5 - 3ppm.
Of course, each pool reacts differently to its environment. Just because your pool is screened in and you have no trees directly overhanging does not mean that you will never get algae. Algae is airbourne. Good maintenance is the best way to ensure your pool remains algae free, weekly brushing of the pool walls releases contaminants that would otherwise encourage algae spores to flourish. Vacuuming weekly is essential to maintain analgae clear pool.
At some point pools will get algae, it does not mean that your pool water is unhealthy and unbalanced, increase the chlorine levels, brush, vacuum, clean and its gone.
A pool store has told us we have high Total dissolved Solids and this is dangerous and we have to empty half of the pool water?
Having a high or elevated TDS can cause the water to look flat or have a salty taste, it can also promote the formation of scale on the finish. If left unchecked the scale that forms on the finish will require professioanl treatment to remove it if indeed it is removable at all.
TDS is the measurement of all of the dissolved organic matter and solids in the pool. If you have a salt chlorine generation system you should deduct your salt level measurement from the TDS total to reflect the correct TDS reading.
TDS that is elevated can only be reduced by draining your pool and refilling with fresh water, ideally NOT well water. The amount you will need to drai isdependant on your final TDS reading.
Ensure your TDS remains between 1000ppm and 2000ppm. 3000ppm is the absolute maximum. If in doubt about how much water to dump obtain advice from a pool professional. The general rule is dump 12 inches then retest, if necessary dump another 12 inches then retest and continue until TDS is in range.
"Chlorine Lock" is one of those terms used in the swimming pool industry that is not widely known by the general public. It describes a state in your pool water where the free available chlorine that is present is unable to do its job as a sanitizer. If the chlorine cannot sanitize then it also cannot burn off organic matter that enters the pool water.
Generally there is only one reason for chlorine lock - Cyanuric acid levels over 100ppm.
Maintain your Cyanuric Acid level at 40-50ppm. Cyanuric Acid is generally known as Stabilizer.
The quickest and easiest way to solve this issue is draining the pool in the same method as you would for high TDS, 12 inches at a time, testing each time, until you reach the desired CA level or between 40-50ppm.
If you do not control the reduction of the CA then be prepared for your pool to "turn". Without the chlorine able to act as a sanitizer your pool will suffer quickly with algae blooms.
Bob Charlton is a Certified Pool & Spa Operator and Inspector with the National Swimming Pool Foundation with 17 years of experience within the pool industry in Florida.