Salt Water Pool Maintenance
Once you convert your pool to a salt water chlorine system you will need to change how you go about caring for and maintaining your pool. In my article about getting informed about salt water pools I dispel the myth that salt water is an alternative to chlorine pools. Even though salt water pools are chlorine pools, and not a chlorine alternative, they do in fact operate differently than traditional chlorine pools. When you switch to an electronic chlorine generator for your pool you will need to change the way that you adjust your chemicals. In addition to this salt pools tend to develop problems that are unique and different from pools using traditional chlorine treatments. None of this is a problem, just slightly different than what you might be used to with your pool up until you made the conversion.
In addition to the chemical treatments there are other things that you should know that are unique to salt water pools. This article will help to highlight some of the important things you need to know about what to expect once you switch to salt water. This includes about when to add salt, and how much to add, as well as how to know if you have a potential problem brewing...and more importantly how to prevent those problems before they even happen!
If you are reading this because you have a salt water pool and you are currently experiencing problems then remember that salt water pools are chlorine pools and you can still (and should) shock your pool with chlorine if you discover that you have zero free chlorine in your water. A salt system makes chlorine slowly over a long period of time so helping your system to establish a chlorine residual in the water with extraneous chlorine treatment is a good idea. This is especially true for pools that struggle with phosphates. Phosphates in specific are hard for salt systems to overcome on their own due to the rapid rate of organic matter growth in the water. A salt water pool is distinctly different than a traditional chlorine pool however when it comes to fighting off algae and cloudy water they can essentially both be treated the same. Just because you have a salt water system does not mean that you need to rely on it completely for delivering the chlorine that your pool needs. That being said salt pools do tend to operate a little differently in terms of regular maintenance and generals areas of concern. This article will highlight some of the things you need to know about now that you have a salt water pool.
In addition to adding a sacrificial anode to your pool it is very important to make sure that your pump, heater, and any other equipment with metal in it is bonded with a heavy guage low resistance wire. The ground wire contained in the power supply is not sufficient - if you can locate an empty bonding lug on your equipment then this is not a good sign and something you should look into further. If you want more information on this subject then watch a few of these pool equipment installation reviews and you will see examples of where to look and what to look for in terms of equipment bonding.
High pH In Salt Pools
One of the very first things that swimming pool owners will learn after they switch over to salt water is that the pH in the pool is constantly going too high. This is a function of the pH of the type of chlorine that salt water systems generate. Different kinds of chlorine have different pH levels which means they will have different effects of the pH levels of the water. Salt water just happens to have a type of chlorine with an extremely high pH. Constant upwards pH drift is just a function of owning a salt water pool. Step one of dealing with this problem is to understand why this is significant.
First, at a pH level above 8.0 chlorine is over 75% inactive. Over 8.2 the free chlorine in the water is over 90% inactive. If you run your pool constantly with a high pH then you do not have as much free chlorine in the water as you think you do...potentially only 10% as much or less which means that many salt pool owners are not staying within the recommended values for free chlorine. You should have between one to three parts per million of free chlorine in your water. However if your pH is over 8.2 because you have not been adjusting your chemicals enough, then you effectively only have 0.1 to 0.3 parts per million of chlorine. Once you convert to salt water you need to understand the importance of why you need to keep your pH levels in balance and the activity of free chlorine in the water is only one of those reasons. Another important factor to consider about high pH levels is how this will affect the saturation index of the water.
Saturation index is the calculation of whether water is considered to be in a "scaling state", a "neutral state" or an "acidic state". This can be calculated using the temperature of the water, the pH level, the alkalinity level, the calcium hardness level, the cyanuric acid level and the total dissolved solids level in your pool. If you are in a scaling state then you are at risk for adverse reactions in your water related to scaling. If your water is in an acidic state then you are at risk for problems related to corrosion. Maintaining a neutral state for your water is and has always been important in swimming pools. However the addition of a salt water chlorinator changes things in that you will be much more likely to have a high pH in the water. You will also have more dissolved solids in the water from all the salt that you need to add. The effect this has is that many salt water pools operate in a scaling state. This can cause scale related problems like calcium scale build up on the salt cell blades, but can also cause problems with staining and mineral leaching within the pool itself.
Simply knowing that your pH will go too high in a salt water pool, and knowing that you need to try to keep your pool out of a scaling state by keeping the pH in the correct range is not enough. How do you actually prevent the pH from climbing so high? Checking and balancing the pH in a salt water pool once per week really is not enough. In most cases the pH will be over 8.0 every time you check the pool water and this will have a detrimental effect on your pool and your pool equipment if left to operate this way for extended periods. The challenge is that no matter how much acid you add to reduce the pH level to 7.4 the pool is always back up over 8.2 by the time you check it again. In theory the total alkalinity is the buffer that helps to prevent the pH from fluctuating dramatically. In a non-salt pool the total alkalinity might be as high as 120 however in a salt water pool you might benefit from having a slightly lower total alkalinity level and also by running borates in your pool water.
If you have trouble keeping the pH of your salt water pool where you want it then lowering your total alkalinity levels to around 70ppm and adding 50ppm of borates to the water should help to keep your pH in the ideal range. At the level of 50ppm borates help to stabilize pH and vastly reduces the pH drift you experience as a result of the high pH of your sanitizer from your salt water system. Additionally borates help to fight algae growth, feel good on your skin in the water, and can help to make your water look clearer, cleaner and crisper. There are no magic secrets to making swimming pool water extra easy to care for and look extra good - but the closest thing we do have to this would probably be the use of borates.
Borates are sold under many different product names such as this Optimizer Plus from BioGuard. It takes quite a bit of this product to initially establish a 50ppm borate level in the water (upwards of 2 lbs per 1000 gallons of water) however once you have established this value you will only need a small amount of product to accommodate for splash out or pumped out water.
You will also need borate test strips to check the borate levels of your water conveniently at home. Borates are not something that is included with most generic water test strips or from most pool and spa free water lab testing counters unless you specifically request this. Having some strips at home will help you to get your initial levels dialed in as quickly as possible.
When you add the borates to your pool this will cause the pH to increase. Part of the process of establishing 50ppm of borates in the water is to reduce the pH of the water with muriatic acid or another swimming pool pH reducer product. Before you attempt to add borates to your pool you need to first establish your total alkalinity level (70ppm) as well as your pH level (7.4) and then begin adding the borates. Do not add borates until you have your pH and alkalinity in the correct ranges!
Adding Salt To Your Pool
Adding salt to your pool, much like adding the borates described above, will require a large initial dose of product followed by only minor maintenance doses to replace that which has splashed out or been pumped out of the pool. Salt does not deteriorate or become used up in the chlorine conversion process so you do not need to constantly be adding more salt. Salt also does not evaporate with the water so even evaporation does not lower the salt levels in your pool. Since dilution is the only solution you therefor want to avoid a situation where you add too much salt to the pool since the only way to lower the levels again will be to pump out some water and replace it with new, clean fill water.
Check Existing Salt Levels - Before you start calculating how much salt your pool will need, and certainly before you add any salt to your pool, you need to know what your current salt levels are. Since chlorine is salt based, if you have been using chlorine in your pool then you will already have some salt in the water...the question is how much? It is not uncommon to see traditional chlorine pools with a few hundred, even up to 1000ppm of salt already in the water. If you did not account for this then you are going to end up adding way too much salt to your pool. This will cost you money and wasted time and effort. Since a large pool might need up to 1000lbs of salt you certainly do not want to overestimate how much you need by 33%. What are you going to do with over 300 lbs of pool salt that you don't need? Not to mention the trouble of pickup up that much salt and locating it to the pool area.
When you add salt to your pool to the tune of hundreds of pounds you are going to need to spend quite some time brushing the pool down to help the salt properly dissolve. Be sure to turn off your salt system during this time as the inconsistent salt levels in the water can cause damage to some systems. When you add the salt simply pour it into the pool and just keep brushing the pool walls and floor until it is all dissolved. The water may become a little cloudy during this process but it will resolve quickly on its own. Do not pour salt directly into the skimmer of your pool...this seems like a super convenient way to disperse all the salt but pumping highly concentrated salt through your pool equipment is not a good idea to say the least. Try to calculate and use a little less salt than you think you need to avoid overshooting the amount you end up with in the pool.
Testing Salt Levels In Pool Water - A common question that tends to come up for salt pool owners is how to tell when you need to add salt? Using salt test strips is one way, and having your water tested by a water lab is another. Finally most salt systems have a digital readout of how much salt is in the water. With all of these ways to test your salt levels how can there be any uncertainty about this? The problem comes from each of these three ways to test salt levels giving you different readings. For example what if the digital readout on your salt system says "low salt" or "add salt" but when you test the water with test strips everything still looks OK?
The digital readout on your salt system may be rendered inaccurate by age, failure or scaling problems on the cell. Any time that your system tells you to add salt you should test the water yourself or have it tested in a reputable pool and spa water lab. You should be able to confirm a problem with the salt level in your pool two ways before you make any actual adjustment to the salt level. For example, the test strips take about five minutes to work. If someone very inexperienced with water testing used these strips to test your salt levels then they may not have let the test finish before reading the results. Pumping out your chemically treated water simply because you added too much salt is a real pain so be sure to verify your salt levels two ways before adding any more to the water. Discrepancies of 300 parts per million or so should be ignored and assumed to be tolerance in the accuracy of the different salt testing methods.
Protecting Your Pool From Salt Water
Something that I have written extensively about is the potential for damage to pools from salt water which is sadly glossed over by most people selling salt water systems to pool owners. The reality is that increasing the salt content in your pool water ten fold will have a ten fold increase in the conductivity of the pool water. Since your pool has many different kind of metals in contact with the water you effectively have a gigantic primary battery operating 24/7 in your backyard. This is something that can be said for any swimming pool, not just salt water pools, but the concerns for damage increase as you increase the salt level.
Galvanic corrosion is the name of the destructive process where electrons travel between dissimilar metals within the water. As you increase the salt levels in the water you make it easier for this process to happen. This means all pools can experience damage from galvanic corrosion however salt water pools will experience these problems much, much faster and to a more serious degree.
A sacrificial anode is installed in the plumbing system in the pump room and is connected to the bonding grid of the pool via a heavy guage low resistance conductor. It does not matter where precisely in the equipment it goes - before the filter, after the filter, or other, so long as it is contacting a pipe that is always filled with water. Another important note is that a sacrificial anode will do little to help you if you do not connect it into the bonding grid, or if you attempt to ground it incorrectly.
Bonding is not the same as grounding - the two are different and perform different functions within a pool system however they do work in tandem to protect the pool. This article that I published talks more about bonding versus grounding for swimming pools but for this example all you need to know is that bonding connects all metal things together electrically, and grounding forces something to have the lowest possible electrical potential. If you were to add a sacrificial anode to the pool system but you did not connect it properly to the bonding grid, instead simply putting a grounding rod in the ground and connecting to it with a wire, then you can experience drastic and accelerated deterioration of metals in the system. The theory behind this is that "ground" on your electrical breaker, and the actual ground of the earth in any particular part of your yard, are not likely the exact same. You can not just introduce new grounding points into an existing system wherever you like. You need to connect to the exact same system that the rest of your pool is connected to. This is done via the bonding grid that was used when your pool was built. You need to locate the existing bonding grid, or connect to the same earth grounding point that the bonding grid connects to. Any other grounding point may in fact have a different potential. If you have two different voltage reference points within a contained system that have different potentials then this would create a non-stop electron transfer between these two points as the system attempts to electrically balance itself. All of this would be very subtle and not visible by feel or by eye...that is until the damage from galvanic corrosion starts to show up or your pool equipment fails very early or repeatedly.
The first time I saw an anti-electrolysis weight 25 years ago I had no idea what it was. When I asked about it I was told that it is used to weigh down the skimmer basket and stop it from floating when the pump turns off. As it turns out this is only a fringe benefit to a much more important process - protecting the pool from galvanic corrosion. I receive a lot of emails from readers of this website asking about if they really need an inline sacrificial anode. Can you just use one of these zinc skimmer weights and get the same level of protection for your pool? No, not really.
I would endorse that all pools should have one of these zinc disks in the skimmer basket however I do not believe that they are sufficient as a stand alone method of protecting the pool against galvanic corrosion. Actually, the inline anodes are not enough either. Pools can and will continue to experience galvanic corrosion even despite our best efforts. What you need to consider is that we are not stopping it, so much as we are attempting to control it, and reduce the amount of damage to the pool...not stop it. Is a zinc disk in the skimmer going to protect the pool from damage? No, it won't. But neither will an inline sacrificial anode. They will however both reduce the potential for damage, and reduce the rate at which metal components experience galvanic corrosion in your pool. A zinc disk in the skimmer is better than nothing, and an inline anode is better than a zinc puck in the skimmer basket. Best of all would be to have both of these, plus ladder anodes and light anodes. The reason why an inline anode is better than the zinc disks is because the inline anode has a water bond connection that is directly connected to the bonding grid of the pool, and the ground of the main electrical service panel. This direct low resistance connection to ground makes sure that stray currents in the water are not finding their own path to ground. Since the disk style anodes are electrically isolated other than through the contact of the water itself this makes them less effective overall than the inline anodes at controlling stray currents, and thereby galvanic corrosion within a galvanic couple (the pool water).
Draining Water From Salt Water Pools
So if you increase the salt content of your pool up to 3000 parts per million or more what are you supposed to do with the water when you need to drain your pool? Can you just drain a salt water pool like a normal pool? The answer to this will depend on where you live and whether there are any restrictions on how you can dispose of salt water drained from a pool. It used to be, when salt systems were less popular, that you could just drain them to the curb like any other pool. In fact, in many areas you can still do this without a problem. In some densely populated areas the amount of salt that is being pumped into city drainage systems is too great and laws are being put into effect that restrict where you can pump out salt pools.
In some areas it is no longer legal to pump water to the street by your house if you have a salt water pool. In these areas the salt levels are building up in local ecosystems and causing problems. The solution to this is to either pump the pool water somewhere onto your own property, or to pump the water into the sanitary drainage system for your home.
Draining Salt Water Pools Onto Your Property - Is it OK to drain water from a salt water pool onto your property like the grass? The truth is that you can drain salt water pools onto your property, supposing you have a suitable spot that is large enough, and the salt content alone will not kill the grass. Chlorine is actually more of a concern than the salt level. Now, over time if you were to drain water regularly from your salt pool into one location in particular it is possible that the salt levels in the soil will build up. If you do have a property large enough to handle the volume of water you need to pump out without flooding onto your neighbors property then you can get away with draining onto your grass.
Draining Salt Water Pools Into Your House Sanitary System - In areas where it is no longer legal to pump salt water pools to the street drainage near your home then you may need to pump the water into the house sanitary drainage system. The sanitary drain for your house collects waste water from your household and delivers it to a water processing plant to clean it. For most pool owners this will mean running a discharge hose into your house and draining into one of your sink or laundry drains. To reduce the potential for flooding you should attempt to drain into the lowest drain access point in your house, or potentially a basement laundry tub.
The most important thing to keep in mind when you switch your pool over to salt water is that you will need to change, or update the way in which you interact with the pool. Most especially the chemical maintenance schedule for your pool will change and you should test your water more often than you used to until you get the hang of your new chemical maintenance program. The addition of borates will help you to maintain optimal pH levels in the pool and the addition of a sacrificial anode will help to protect your pool from the potential for damage from galvanic corrosion. If you want to make sure that your salt system is installed correctly you can read this article on how to install a salt chlorinator on your pool which highlights many of the common mistakes that people make when installing pool salt systems.
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