2/16/2011

A Better Pool

Asking for some of these items on a pool will have very little impact on the initial cost but will improve both the sustainability of the pool and the water quality in addition to lower operating costs. We have not included an automatic cover in this list because the majority of new residential pools in our area have covers. 

What
Why
Six hour turn over
A six hour turnover is the standard for every commercial pool, why should your customers have anything less? Especially when the incremental costs for this standard is probably less than $300 for a pool. Better circulation means you are filtering organic material rather than treating with chemicals.  It also reduces the time to open a pool and improves the water quality. 
A return every 20 feet
Stagnant areas in the pool are potential breeding grounds for algae.  Proper distribution of the return water costs very little, improves water quality and helps to eliminate temperature variations in the water.  
Variable speed pumps
These pumps have four important benefits: lower operating costs, higher reliability, greater versatility, and when operating they make as much noise as a human whisper. 
Cartridge filters
A cartridge filter can be easily cleaned on site, filters out smaller organic material than a sand filter and does not require backwashing.  A sand filter requires backwashing periodically to clean the filter. This wastes hundreds of gallons of pool water every time the filter is backwashed. The make up water must then be balanced and reheated. Has your make up water (source) been tested? Testing your source water for metals (copper, iron, manganese), along with all other water conditions, is critical and often overlooked.
LED lights
LED lights last five times longer than normal incandescent pool lights and use about 25% of the energy. In addition, they can provide color lighting which adds to the pool’s enjoyment and atmosphere for the owner.
Flow meter
You cannot confirm proper flow for either turnover or a variable speed pump without a flow meter. It costs a pool builder less than $70 and they can be installed at the time of the installation.

You should also consider:
  1. Soil tests in the initial design stages of the project.
  2. Electronic water level controllers
  3. What is your policy on backfilling of the pool excavation with expansive soils?
  4. Rigid PVC vs. flex tubing for plumbing.  Which is best for your project?
  5. Pressure side vs. suction side vs. robotic pool cleaners.
  6. Spare cartridges for a cartridge filter.
  7. Chlorine generation or a UV system for pool sanitization. 

2/04/2011

pH Drift and Salt Pools

Salt pools are great. Just ask anyone who owns or uses one. Generating and controlling your chlorine on-site eliminates the need to buy and handle chlorine tablets. In addition, the water feels soft, silky and inviting. One of the main benefits to the salt pool owner is less maintenance but this doesn’t mean that salt pools are maintenance free. You still need to test, balance and clean your pool on a regular basis.

Our chlorine generation (salt pools) customers typically have us out once a week for service and cleaning but sometimes this isn’t enough.  The National Pool Industry Research Center conducted a study monitoring salt-chlorinated pools on a weekly basis. With weekly adjustments to the chlorine levels, the pool’s free chlorine (the good stuff) remained stable throughout the study. The water’s pH, however, was more difficult to control. Every time the pH was adjusted into the “ideal” range of 7.2-7.6, it was found to drift up to 8.0 or above within 3 days or less.

Experienced service technicians have noticed this upward pH drift for several years now. Muriatic acid is the most frequently used chemical to combat this drift and lower the pH back to acceptable ranges.

It’s important to remember that your pool’s water conditions are dynamic and not static. The chemistry can change, due to many factors, in a matter of just 24 hours. As evidenced by the IPSSA’s study and our field experience, this is especially true for pH levels in salt pools. Even though we may visit your pool for service once or even twice a week, we strongly encourage our customers to take part in the water testing while we’re not there and alert us if something is out of range. 

Understanding your pool’s chemistry trends, chemical needs and characteristics is derived from frequent water testing (including your source water). What the pool owner or the pool service professional doesn’t want is a perfectly balanced and clean pool Wednesday afternoon and then potentially cloudy, scale-forming water come the weekend.

Turnover Rate

A high turnover rate is not good for business, but it is important for pools...and unfortunately often ignored in the pool construction process. Turnover in the pool industry is defined as "The period of time required to circulate a volume of water equal to the pool or spa's volume." The minimum standards for turnover are 12 hours (per ANSI/NSPI-5 2003 standards) and 6 hours for commercial pools per the standards established by the MN Department of Health.

Turnover is important because it is much easier and efficient to filter the water than to treat it with chemicals. Pools with a longer turnover time period require more chemicals to treat the water, have more issues with water clarity, are more susceptible to problems with algae and typically take longer to open in the spring.

The incremental cost to design and install a pool with good versus poor hydraulics is minimal. 2" plumbing can carry 77% more water at the same velocity than 1.5" plumbing. 3" plumbing can carry 224% more water than 2" plumbing. The incremental cost for plumbing is pennies per foot and the labor is the same. Unfortunately, we see many pools with 1.5" plumbing that provides very limited flow. When we calculate the maximum flow they can achieve through the plumbing, we know their pool has poor circulation and most likely high operating costs.

What should you do? Our recommendation is that you insist your pool or pools are built to a high standard, or a six hour turnover rate. You should also insist that your pool contractor provide a flow meter installed visibly on the equipment pad in order to verify proper flow. Most flow meters cost a pool contractor under $70.00 and are easily installed.

The pool builder should be able to tell you what flow he or she has designed but to verify, the calculations are fairly simple. The volume of water in the pool is:  Pool surface X average water depth X 7.5 = Gallons in the pool. To determine the gallons per minute to achieve a 6 hour turnover, divide the total gallons by 360. For example, a 20' x 40' pool with a deep end of 8' and a shallow end of 3' would have approximately 33,000 gallons of water. The minimum flow to achieve a 6 hour turnover rate would be 92 gallons per minute.