What is a Pool Testing Kit and Do I Need One?

We have a lot to do to properly maintain our swimming pools.  We have to get the dirt and debris out, make sure we are circulating the water, make sure our equipment is operating properly, and balance the water chemistry.  Balancing the water chemistry is the most important thing you need to do for your pool.  Not only does well balanced water look amazing, but it feels great to swim in.  The most important part is it ensures your pool or spa water is safe.  But how do we know what chemicals are needed to make this happen?  Test, test, test!  Never add chemicals to your swimming pool without testing it first.  Unbalanced water can be scale forming or corrosive which can make the sanitizer less effective, and unsafe for use.  It can also be damaging to your equipment, plumbing and surface.  So, how can we test our water and what should we be looking for?

Test Strips

While not quite as accurate as a reagent test kit, test strips are a perfectly acceptable way to test your swimming pool water.  Please follow the directions on your individual brand of test strips, but here is how they work in a general way.  Most test strips test for total chlorine (or bromine), free chlorine, pH, alkalinity, calcium hardness and cyanuric acid.  You dip the strip into the water, shake off the excess water and lay the strip flat for approximately 15 seconds. Read you results within 60 seconds max or they are no longer good.  You read your results by matching the colored squares to the corresponding field on your test strip bottle.  It will give you a spectrum and they will usually mark the “in range” readings.  Basic rule:  If its high, lower it.  If its low, raise it.  Use the appropriate product to do so.  Always follow the products instructions and wear the proper PPE (personal protective equipment) when handling chemicals.

A Reagent Test Kit

These are much more precise than test strips, but allow a lot more room for operator error.  You can buy a test kit in different sizes.  What I mean by “size” is the larger the kit, the more fields you can test for.  You don’t want to skimp and buy a kit that only tests for total chlorine and pH.  This is because we have to be able to determine if we have any combined chlorine.  We also cannot get an accurate pH reading without comparing it to our alkalinity reading.  I recommend the Taylor brand test kits.  Whatever size you get your test kit will come with  testing decanters where you will put your sample water into.  You then add the called for drops of a numbered liquid reagent.  The little reagent bottles come in your kit and are numbered and color coded.  

Pro Tip:  When using a reagent bottle, always hold it directly up and down over your sample water.  Don’t flick your wrist from an angle. Gently apply pressure to the bottle, but do not squeeze.  The bottles are designed to produce “gravity drops, which are even sized drops.  If we don’t have even sized drops, we don’t have an accurate test.

Reagent test kits involve counting drops, spinning decanters and comparing colors, like on a test strip.  It can sound overwhelming, but it’s really quite simple one you see it done.  Having managed a swimming pool supply store for 7 years, I always invite my customers to bring in their test kit so I can show them how to use it.  You may be able to find a friendly local pool professional that will do the same.  This brings us to our next testing method.

Swimming Pool Store Water Tests

By far the easiest way to get an accurate water test is to bring in a water sample to your local swimming pool supply store.  Most places test for free or a nominal fee.  The pool professional will then take your water and manually test it with a reagent kit, or use the newer technology of a “Spin Lab”.  A spin lab requires a minuscule amount of swimming pool water which is put into a special disc.  The disc is then inserted into a spin lab which spins the water around.  This photometer method uses color and light, much like a regent test.  The groovy part about going to a swimming pool store is they will usually give you a report which shows you where your water is, where it should be and how to get it there.  It produces the correct amount of any given chemical based on your results and your swimming pool size.  As a courtesy, if you do take your water in to be tested, you should buy your supplies there as well.  Spin discs cost up to $3 per disc. See you poolside!