Posted by: Fluid Dynamics Pool and Spa Inc. | December 4, 2010


In part 1 we explored the basics of building a green swimming pool.  Things like: Variable Speed Pumps, Low-restriction plumbing systems, LED lighting, and Chemical monitoring and regulation.

Here in part 2 we will explore some of the additional things that can also be considered when building a Green Pool.

Solar options: (the ultimate Green improvement)

One thing that should be looked at on a project is the orientation and shape of the roof structures available on-site.  If an appropriate roofline is available then adding solar thermal panels can be explored.  This will extend the swimming season considerably, as well as significantly reducing the demands on the pool heater.

Photo Voltaic (PV) electric generating systems can also be explored. These systems can be used offset the electrical consumption of just the pool itself, or can be sized to generate enough electricity to power the entire home as well. 

Recent changes in Washington have significantly improved the tax benefits of installing these systems, offsetting some of the costs involved, be sure to check with a local Solar Contractor for further details.  It may be surprising just how affordable these systems have become.

Pool Covers: (Inexpensive Green option)

Pool covers come in different varieties: Automatic Safety Covers, and simple floating bubble covers (also called solar blankets).

Both covers have similar Green impacts on the swimming pool environment:  They significantly reduce the evaporation from the pool itself, decreasing a pools demand for our precious water resources.  Also the cover acts as a blanket for the pool at night.  At night the temperatures often drop below that of the pool, causing the pool water to cool off.  Covers reduce this overnight heat loss, which results in reducing the demands on the pool heater to maintain a comfortable swimming temperature for the bathers.

By far the least expensive Green upgrade that can be installed on any pool is the simple floating solar blanket.  These generally only cost a couple hundred dollars (or less) and as discussed above, significantly reduce water usage, plus helping maintain the water at a more comfortable temperature.

Automatic Safety Covers offer the same Green benefits as the simple floating solar blanket, but also have the added benefit of creating a safety barrier for small children, or animals; protecting them from unauthorized or unwanted access to the swimming pool.

Green Chemicals?: 

Ozone is a gas that is found in the upper atmosphere here on Earth. We are all familiar with the “hole in the ozone layer” which has been well publicized in the news media.  Ozone also occurs in nature during lightning storms.

Ozone is a very powerful oxidizer, much stronger than the traditional oxidizers (chlorine and bromine) used in swimming pools.  Ozone is currently utilized within the bottled water industry to purify their water for consumer consumption.  In a pool with an appropriate sized ozone system, the result is a bottled water quality swimming environment.  With a large enough system it is possible to reduced the demand for chlorine by 90% – 95%.  And since the ozone is generated onsite, the overall Carbon Footprint is dramatically reduced with this configuration.   These systems yield bottled water quality water that is pristine, and crystal clear all the time. If the budget allows for one of these systems, the end result is truly amazing.

 Green Heating:

Technology exists which will allow the home’s air conditioning system to transfer the heat it generates into the swimming pool.  This synergy allows both systems to perform more efficiently.  The AC system is cooled by the pool water, and the pool water is warmed by utilizing heat that would normally just be lost into the atmosphere.

Heat Pumps can be utilized as well.  These systems use electricity rather than gas (natural or propane) to heat the pool water.  These systems should only be considered Green when they are combined with an appropriately sized on-site PV electrical generation to offset the increased electrical demand these systems instill.

Posted by: Fluid Dynamics Pool and Spa Inc. | December 4, 2010


You could always not add chlorine for a few weeks and you will end up with a Green Pool, but that’s not what I’m referring to.

Green Pumps:

We have implemented a program utilizing both Variable Speed Pumps, and low restriction plumbing systems with great success.  We design our pool plumbing systems using the CA residential building code, which is known for being the one of the most stringent codes in the country when it comes to mandating energy efficiency.  By utilizing large PVC pipes (often 4” or larger) we are able to dramatically reduce the plumbing restriction, resulting in significantly lower energy costs.  We program our systems to run for 12+ hours a day at very little cost to the client.  Our average system costs just 40 cents a day to run.  A typical 1.0 HP pool pump costs about the same to run for only 1 hour. 

Green Lighting:

Next we looked at the pool lighting systems.  We no longer install 120 volt light fixtures in ANY pool that we work on!  Fiber-optic lighting was a noble early attempt to solve both the safety issues and the energy consumption issues posed by standard high voltage pool light fixtures.  But these systems had some drawbacks to them, and the high price was often a HUGE detriment to most system installations. 

We now install only 12 volt LED pool lighting systems.  Not only do these systems use 95% less electricity, BUT they also allow us to completely remove the underwater death charge that is the standard 120 volt light fixture.  We have all seen the MythBusters episode where they drop a running hairdryer into a bathtub, and watched the tragic results that followed!  YET many pools continue to be built with a similar 120 volt fixture permanently installed under water.  I know that with a properly installed GFCI the risk is greatly reduced, BUT what happens if an uninformed pool service-person, or homeowner decides to remove the GFCI because he can’t get it to stay re-set?  Now it is quite possible that there exists a potentially DEADLY situation.  Now you as a builder I am unlikely to be blamed for something like this, BUT I would rather just install a safer system in the first place, and then I KNOW that there will NEVER be any issues in the future, no matter who works on the pool down the road. This is not only environmentally responsible, but socially responsible as well.

Green Chemicals:

Once we got our plumbing systems fine tuned, we turned our attention to chemical consumption.  We have started installing automatic chemical feeding systems on our jobs, and are able to reduce the overall chemical consumption necessary to keep the pools clean.  With this type of system, we can set it to maintain a specific sanitizer level all the time, without ever over-chlorinating the water, needlessly waisting sanitizer.  This is not only more Green, and good for the pocketbook, BUT it also reduces the overall “carbon footprint” generated by the pool itself.  If less chemicals are used, then there is less manufacturing necessary, and less pollution generated transporting those chemicals from the manufacturer… to the distribution house… to the retail outlet… and then finally to the backyard pool… Not to mention the fact that you have reduced the amount of hazardous material out on our local highways.

These are the basic Green Building techniques that we implement on every project we build.

Posted by: Fluid Dynamics Pool and Spa Inc. | March 5, 2010

Hydraulics Pt. 3 (Why you should care)

As we have been discussing in previous posts, the importance of proper hydraulics in a swimming pool are very important when building a pool.

Many pool builders have a standard hydraulic plumbing template that they use for EVERY POOL they build, whether it is a 5,000 gallon cool off pool, or a 45,000 gallon lap pool.  We use a sophisticated hydraulics mapping program to evaluate every project to determine what plumbing to use on each individual project.

As we learned in the last post, there are minimum hydraulic specifications for plumbing set out at both the national and local level.  Many pool builders do not even adhere to these specifications, and of the ones that do, most of them are only concerned with making sure they meet the minimum requirements.

MINIMUM specifications are just that, the least that can be done in order to remain legal.  This is not a business model which I strive for.  I like to provide a quality product, not just install the minimum I can get away with. 

We adhere to hydraulic limits far more stringent than those laid out by the code.  We try to limit our line velocities to 4.5 fps suction and 6.5 fps return (as opposed to the 6fps suction and 8fps return in the code). 

Now you may be saying “SO WHAT! If the plumbing is within the legal limits, then it should be fine.  Why should I spend the extra money on bigger pipes?” 

Here are a few factors to consider.:

1) The internal hydraulic stress on the pipes and fittings.  The higher the speed that the water flows through the pipes, the more quickly the joints will fatigue, and eventually fail. 

2) The efficiency of the pump.  The larger the pipes are; the SMALLER the pump can be and yet still provide the same amount of flow through the system.  If there is less resistance in the plumbing system because larger pipes have been used, then a smaller pump can be used to flow the same amount of water. 

The size of the pump has a direct effect on your monthly electric bill.  A larger pump is more expensive to run every day.  It is not uncommon to be paying upwards of $0.28 per Kilowatt (KW) hour for electricity here in CA.  A standard 2.0 hp pool pump consumes about 2.2 KW per hour costing about $0.60 per hour, or $3.70 per day.  By contrast, a 3/4 hp pump consumes just under 1.3 KW per hour, costing only $0.36 per hour, or $2.18 per day.  That difference is impressive, but not nearly as dramatic as when a variable speed pump is installed on a pool with proper hydraulics.  We will explore Variable Speed Pumps more in our next blog post.  By using Variable Speed pumps, and upsized plumbing we are able to reduce our energy consumption to 125 watts; or 0.125 KW.  This has a dramatic effect on electric bills.  We are able to lower the DAILY cost to run the pump down to about $0.63 (similar to running a 2.0 hp pump for 1 hour!)

So even though 2 pools may look the same, 1 pool will cost $3.70 per day to run the equipment, while another will cost only $0.63 per day.  I assure you that the pool that costs $3.70 per day to run will be less expensive to build in the beginning, but it will cost over $1,100 MORE per year, EVERY YEAR, to maintain.  Most people who build a pool plan on staying in that house for a while.  The $1,100 per year utility bill savings will definitely add up over the lifetime of that pool.  

This is definitely something to think about next time you are interviewing pool builders, and wondering why there is such a wide difference in pricing.  One service that we offer our clients is an energy audit for every new construction project we undertake.  We have a very sophisticated  hydraulics program which will evaluate all of these parameters, and estimate what the electrical consumption will be; based on the equipment being installed for that particular job.  Ask your pool builder if he can offer you a similar type of  hydraulic mapping service as well.

For more information on hydraulics or anything else related to pools, please feel free to check out our website at .

Posted by: Fluid Dynamics Pool and Spa Inc. | March 5, 2010

Hydraulics Pt. 2 (Velocity Kills)

Swimming pool hydraulics are often overlooked when a client is interviewing a potential pool builder, but as you will learn hydraulics have a huge impact on the overall cost of ownership of you pool.

One of the first factors to consider when evaluating pool hydraulics is to determine how big the pool will be.  We need to know how many gallons are in a pool in order to determine what our flow rate needs to be. 

Let’s use an example of 30,000 gallons (a medium/large residential pool).  The California code (CA Title 24) tells us that we need to circulate ALL 30,000 gallons of pool water in a 6 hour period of time; this is called turnover time.  So when we divide 30,000 by 6 hours we determine that we need to flow 5,000 gallons per hour through the plumbing.  Within the pool industry we use gallons per minute (gpm), not gallons per hour.  So we take the 5,000 gallons per hour and divide by 60 (60 minutes in an hour) which gives us 83 gpm. 

Now that we have calculated that we need to have a flow rate of 83 gpm we need to determine what size plumbing to use. 

Just like on the freeway, pipe has a speed limit.  Rather than MPH; plumbing speeds are measured in feet per second (fps).  When we reference the national plumbing code we see that 8fps is the MAXIMUM speed (velocity) allowed for any plumbing, anywhere.  Here in California we look to the California code (CA Title 24 again) which states that 8 fps is the max velocity for return line plumbing, BUT 6 fps is the max velocity for suction plumbing.  Referencing Plumbing Velocity Charts we determine that at 83 gpm 2″ pipe will have a velocity of 7.9 fps, which is OK within the code (just barely) for return line plumbing ONLY.  We next determine that 2 1/2″ plumbing has a velocity of 5.6 fps, which is also OK within the code.  These are the MINIMUM specs that can be used to build this pool, and still be within the code.

One of the factors that get missed by many pool builders is the Velocity limits of the skimmers being installed.  Currently the highest flow rate traditional skimmer used in the pool industry has a MAX flow rate of 75 gpm; and some have flow rates much lower (even into the 20’s).  So in the example used above at least 2 skimmers would be required.

Make sure you discuss these hydraulics questions with your pool builder to make sure that he has fully thought this all through.  You may find that he has simply applied his “standard hydraulic template” to your pool, and has not given your particular project the attention it needs.  (That should make you question whether the rest of the project will get the attention it needs during construction.)

Now you may be saying “SO WHAT! If the plumbing is within the legal limits, then it should be fine.  Why should I spend the extra money on bigger pipes?”  There are a few factors to consider which we will get into in part 3 of this hydraulics discussion.

For more information on pool hydraulics, or anything else related to pools, please check out our website at .

Posted by: Fluid Dynamics Pool and Spa Inc. | February 1, 2010

Hydraulics Pt. 1

To most people a pool is a pool.  They look similar, hold water (hopefully), and are a great place to cool off in the summer.

Why then do some pools which look almost identical cost so much more?

There are a number of factors involved in this, which we will discuss over the next few blog entries.  The first category we will tackle is hydraulics and plumbing.

Most people don’t pay attention to what is underground on a particular pool.  In fact it is very difficult to determine what is underground without digging things up.  A typical pool has almost everything underground; the plumbing lines, electrical lines, gas lines, auto fill lines, light niches, sub-structural support mechanisms (such as caissons), drainage basins, hydrostatic valves, surge tanks,communication cables, in fact the pool itself is in the ground.  For this reason it can be very difficult to evaluate a pool based only on what you can see.

One of the areas that many “budget” pool builders skimp on is the pool hydraulics, and more specifically the size of the plumbing lines to and from the pool.  Now you may be thinking… “It’s just some plastic pipe! How hard can it be?”  For the most part it is not difficult, but there are a number of factors which must be considered when determining how to attain proper hydraulics for a particular pool. 

In Southern California, where we build most of our pools; a typical pool has 1 skimmer and 3 return lines.  Most builders have a standard plumbing hydraulic template that they use for EVERY POOL they build, whether it is a 5,000 gallon cool off pool, or a 45,000 gallon lap pool.  (We use a hydraulics mapping program to evaluate every project to determine what plumbing to use on each individual project)

There are laws which govern what pipe size can be used in a pool, but many builders (and almost all building departments) are either unaware, or don’t care about adhering to these laws.  The law does not say “Use this size pipe on this type of pool”, rather it gives a number of hydraulic parameters which need to be looked at to determine what pipe size needs to be used. 

These factors include: The size of the pool, the desired turnover rate of the pool, the intended use of the pool (is this a showpiece that will rarely be used for swimming, or will all the neighborhood kids be swimming in it daily), environmental concerns (are there large mature trees which will be dumping leaves in the pool regularly), and the overall environmental impact of the project itself.

Check back next time when we will get into more of the fine details of these different factors.  You can also get more information by visiting our website at .

Posted by: Fluid Dynamics Pool and Spa Inc. | August 14, 2009

What’s the phuss about phosphates?

Phosphate treatment has really taken hold within the pool industry in the past few years, but what are phosphates and why should you be concerned.

One of the other major concerns, and why phosphate treatment is much more common now than it was even just 4 years ago, is that high levels of phosphates in a pool will have a significant impact on your salt water chlorination systems performance.

Phosphates are one of the main ingredients found in plant fertilizers.  Since Algae is a simple plant the presence of phosphates in the water will have an impact on the difficulty controlling algae in your swimming pool.  The more phosphates that are present the more difficult it becomes to kill and control the algae in your pool water.

If you find that 1) your pump is running an appropriate amount of time and you are turning over your pool at least 1 time a day, 2) you have plenty of FREE chlorine in the pool, and 3) your PH and alkalinity are balanced, but you continue to have an algae problem… then it’s probably time to check for phosphates. 

So what do you do?

There are simple tests which can be performed to evaluate if your pool has phosphates present, and the approximate concentration of phosphates in the water.  There are liquid tests, tabs, and test strips available to accurately tell what your phosphate readings are.  We have found the test strips to be fairly accurate, and BY FAR the easiest tests to perform, and analyze. 

I personally prefer to have no phosphates in the water at all, but in reality we generally do not treat phosphates until they reach about 250 ppb.  Treatment involves adding the phosphate removing chemicals to the pool, typically through the skimmer while the pool pump is running.  This rapidly disperses the chemical throughout the pool, allowing it to have the maximum effect.  The chemical precipitates the phosphates out of the water, and they fall to the pool floor, where they can be vacuumed up.  We usually recommend that the pool pump run for 24 – 36 hours continuously during this process, which will speed the progress along.

Once the process is completed the filter will need to be taken apart and thoroughly cleaned (and it’s not a fun process). 

We usually recommend that an additional test be performed to confirm that all the phosphates have been removed from the water.

Not all phosphate removers are created equal!  There are dramatic differences in the effectiveness across different brands.  Read the directions  carefully, and compare the dosage rates to see which ones are the most effective.  These chemicals are not cheap, but when administered properly the result is a pool that is much easier to maintain throughout the year.

Posted by: Fluid Dynamics Pool and Spa Inc. | March 30, 2009


Welcome to my Blog.  My name is David Penton and I am the owner of Fluid Dynamics Pool and Spa in Orange County, CA.  I have been involved in the pool industry since 1992.  My business offers everything from new pool construction and backyard remodeling, to expert repairs, and even weekly maintenance.  One of the things that makes us unique is the fact that we are a fully integrated swimming pool business.  Not only do we keep up to date with the most cutting edge trends, and techniques in pool construction, but since our service guys see the pool every week for years after construction is completed, we also see what works and what doesn’t.  We also service many pools that we didn’t build, and we are constantly critiquing what we see, and evaluating how things could have been done better.    

The purpose of this blog is to discuss some of the things that we have learned over the years, unveil some of the mysteries involving swimming pools, look at the latest trends in pool construction, and generally offer helpful information for anyone who owns a pool or is thinking of building one in the future. 

I hope you enjoy this and find it useful.  Please feel free to post a question if there is something that you would like covered here.