Crystal Clear Water. Expert Care. Zero Hassle.
Weekly Pool Service
Chemistry balanced perfectly. Equipment checked. Water crystal clear. You swim, I handle everything else.
Light Repairs & Tune-Ups
Catch problems before they’re expensive. Optimize your system to cut your electric bill. Keep equipment running longer.
Expert Consultations
Second opinions on repairs. Equipment upgrades. Water chemistry issues driving you crazy. Straight answers from someone who knows.
About Me
With over fifteen years as a Pool and Spa Contractor and ten as an electrician, I offer a wide range of expertise. Semi-Retired, I now offer Weekly Service, Light Repairs and Consultations.
I offer a mastery of water chemistry, including the Calcite Saturation Index. My methods will virtually eliminate the causes of waterborne illnesses as well as prolonging the life of your investment
Given my years of experience with installation and repairs, I can spot minor issues before they become major ones. And, given my thorough knowledge of the National Electrical Code, I can advise you on how to keep things safe
I have a thorough understanding of water hydraulics which allows me to “Tune” your pool for greater savings
And finally, I always tell the truth and I keep my word.
Pondering the deeper mysteries of pool care? Plunge into the more technical aspects by checking out the “Deep End”
Why Choose Clearwater
I tell the truth. I keep my word. Your pool will be dialed in.
- 15 years as pool contractor + 10 as electrician – I actually know how this stuff works
- Master of water chemistry – Including the Calcite Saturation Index most pool guys ignore
- Prevent expensive problems – Spot issues before they cost you thousands
- Cut your electric costs – Hydraulic tuning that actually saves money
- Electrical Code expert – Keep your family safe, not just compliant
The Deep End
Learn more about the science behind my process.
Swimming Pool chemistry is like having a project where 10 different machines are doing 10 different jobs and each job affects all of the others. If one machine breaks down, the whole project goes South. With that in mind, let’s get started.
Of course, one of the main things we want to do is sanitize the water for safety. To that end, we want the sanitizer to be as effective as possible.
When we add liquid chlorine to water, it breaks into two molecules – one will kill stuff, the other does very little. In pure water, at a pH of 7.5, it’s about a 50/50 split. At a pH of 8.2, it’s about an 80/20 split (the good stuff is the 20%). So, how do we keep the pH where we want it? Glad you asked!
pH is affected by the Total Alkalinity (TA) level. Too high and the pH continually creeps upward – too low and it can become erratic. The trick is to keep it in that sweet spot right in the middle. Then, week after week, the pH stays stable. One bonus is that we use way fewer chemicals. And, as you’ll see, this balance keeps the whole project running smoothly.
We also need for the chlorine to stay in the water. In pure water, in an outdoor pool, chlorine will be lost to UV radiation within a few hours. So we need something to hold the chlorine in the water. Enter Cyanuric Acid (CYA). CYA forms a weak chemical bond with the chlorine molecules. The bond is strong enough to hold the chlorine in the water but weak enough where it can get loose to do its work. We just need to keep the proper level of CYA in the pool – if it gets too high, we have to add more and more chlorine to compensate. MINIMUM Free Chlorine should be 7.5% of whatever the CYA level is. BUT, it should be maintained at a level a bit above that to provide a cushion for those times when a lot of folks go in the pool, there’s a lot of dust, debris, etc.
Next, are phosphates. Orthophosphates are plant food – algae is a plant. Does it make sense to try to kill the plant (algae) on the one hand and then feed it on the other? Nope! It’s an easy fix though – we just add phosphate remover and test monthly.
Then, we measure Calcium Hardness (CH) and adjust as needed to balance the Calcite Saturation Index (discussed below).
Lastly, we measure Total Dissolved Solids (TDS). TDS measures the concentration of dissolved inorganic and organic materials. Everything added to the pool—chlorine, other chemicals, and contaminants like body oils, sweat, and lotions—eventually increases TDS.
Now we tie it all together to calculate the Calcite Saturation Index (CSI). Note: Formerly, the Langelier Saturation Index was used – the CSI is more accurate.
It is calculated using temperature, TDS, pH, TA, CH and CYA. It is a measure of how saturated the water is with Calcium Carbonate. Too saturated and the water will get rid of it, leaving calcium deposits on tile (Bathtub Ring), heater heat exchangers, etc. Not saturated enough and it will find Calcium and ‘eat’ tile grout, plaster, heater heat exchangers, etc.
Bottom line, this is complex but not complicated. Initially, it may take a bit of work to get everything balanced and all the parts happily working together. But, after that, very little is needed. Put another way, initially, it’s like driving Highway 17 to San Jose. After that, it’s like driving I-5 to LA!
Chemistry can be perfect but the sanitizer must be delivered to every cubic foot of water in the pool. Plus, all of the waste material (debris falling in the pool, dust, dead algae, bacteria, etc.) must be removed from every nook and cranny.
This is done, of course, by using the pump to move the water from the pool, through the filter and back to the pool. So, how long should we run the pump every day?
A general rule of thumb is that all the water in a residential pool should be run through the filter once per day (one turnover). Pools that are used a lot or have a lot of debris going in them may need to be turned over more often. Naturally, one turnover of a 20,000-gallon pool will take longer than a 15,000-gallon pool. Here’s how we calculate it:
Let’s say that the piping is 2” PVC, which is the most common. To begin with, you can only push water through a pipe so fast (velocity) before it starts creating turbulence that actually slows the water down. A velocity of 6’ per second is the sweet spot.
In a 2” PVC pipe, we use the formula below to calculate the maximum gallons per minute (GPM) we can move through the pipe without slowing it down.
GPM = 2.448 x ID² x v
Where:
2.448 A constant used to convert cubic units to gallons per minute
ID = The actual internal diameter of the pipe (inches).
v = The velocity of the water (feet per second).
2.448 x 2.047”² x 6’ per second (velocity) = 61.546 GPM
Then, we calculate how many gallons are in the pool. We first calculate how many cubic feet of water are in the pool. On a rectangular pool, we use the simple formula:
Length x Width x Average Depth
So let’s say we have a 30’x 15’ pool that is 8.5’ at the deep end and 3.5 ‘ at the shallow end.
30’ x 15’ x ((8.5+3.5)÷ 2) = 2700 cubic feet
There are 7.48 gallons in a cubic foot so,
2700 ft3 x 7.48 = 20,196 gallons in our pool
And, at 61.546 GPM, I can run my 20,196 gallons through the filter in 328 minutes or 5.47 hours, which achieves my one turnover per day.
But, I want to save on electricity!
Right! Most pools these days have variable speed pumps. The Pump Affinity Law states that, if I cut the speed of the pump in half, I cut the electrical usage 8 times!!
Top speed for a pump is 3450 RPM. I want to run the pump at a higher speed for 4 hours/day with the cleaner to really mix the water thoroughly so that my sanitizer is, for the most part, getting to every corner. Plus, this stirs up the waste products mentioned above so they can be picked up by the filter.
On most residential pools, to achieve (but not exceed) my 61.546 GPM, I can set the pump high speed at 2200-2500 RPM (which is almost half of 3450 RPM so almost 1/8 the electricity). So, in 4 hours, at my 61.546 GPM, I will have filtered 14,771 gallons. I can now filter the remaining 5425 gallons at a lower speed (and even less electricity!). I want to set the pump speed as low as possible and still get 20 GPM, which is required to fill the filter all the way up (otherwise, the filter will be half full of air which degrades the elements plus it’s only filtering half the water). So, 5425 gallons ÷ 20 GPM = an additional 4.51 hours to filter the remainder of the water.
Sounds good, right?
Nope! Even if we run 20,196 gallons through the filter, some of the water was run through twice while some of it hasn’t been run through at all. Actually, if we kept the pump running continuously at 61.546 GPM, it would take 10 turnovers to filter all of the water! So, I would have to run the pump for 10 x 5.47 hours or 54.7 hours for one turnover per day, which is impossible.
Instead, we just run the pump as follows:
4 hours per day at 61.546 GPM (which is 2200-2500 RPM)
20 hours per day at 20 GPM (which is 1000-1300 RPM)
Since the pool is not in use constantly like a commercial pool, the added time at the lower speed gives it time to filter most of the water before it can get dirty or become contaminated. And, since it’s running at the lowest speed, it’s using very little electricity.
Pools set up this way, along with proper chemistry, will have crystal clear water. A good measure of water clarity is to imagine laying a newspaper on the bottom in the deep end. Although it’s too far away to actually read, it should be perfectly legible.
Many times, when I explain why the National Electrical Code dictates a particular thing, I’ve heard the response, “Oh, that’ll never happen!”. The thing is that it did happen – that’s why it’s in the Code.
Every three years, through a consensus of volunteers, including engineers, contractors, and inspectors, and then approval by the American National Standards Institute, the Code is updated. And these updates are to address issues that were found to have caused injury or death.
One great example as relates to pools is the advent of GFCI Breakers. In the old days, we would just put, say for example, a regular 15 amp breaker on a pump. This type breaker is designed to protect equipment and wiring from circuit overload, which could also cause a fire. It does not protect the swimmer.
In response to this danger to swimmers, Charles Dalziel, a UC Berkeley electrical engineering professor, invented the ground-fault circuit interrupter (GFCI) in 1961 to prevent electrocution. He patented the device in 1965 after researching the effects of electric shock on humans, determining that a 5-milliamp threshold was necessary to protect people from fatal shocks. Code then required that GFCI’s be installed on all pool pumps.
A further evolution of the Code: While GFCI’s were used on Pool Pumps for a long while, they were not used on gas pool heaters. The committee later determined that an electrical fault in the heater circuitry could also introduce electricity into the water so now GFCI’s are also required on the heaters.
Simply put, I don’t do a thing because Code tells me to do it – I do it to save lives.
Contact Me
Clearwater Pool and Spa
6101 Gushee Street
P.O. Box 147
Felton, CA 95018
California Contractor’s License #1067473