Can Too Much Chlorine Damage Your Pool?

There are many things that can cause damage to our pools.  This includes the pool’s surface, the plumbing, the equipment, and even us as swimmers!  Let’s talk about some of the things that can cause damage.

Too Much Chlorine

Yes, too much chlorine can cause damage.  Let’s start with the bathers.  They can get irritated skin, eyes, and even lungs from too high of a chlorine level.  Too much chlorine is also corrosive to a swimming pool’s plumbing.  It can eat away at the vessel itself, damaging the plaster or pebble tech.It can bleach out vinyl liners.  It can eat away at your equipment too.  Especially if you own a heater.  The heat exchanger gets eroded, spilling copper into your water.  Think chlorine turns your hair green?  That is actually a myth.  It is actually chlorine’s reaction to copper in the water that causes that.

Too Little Chlorine

Too little chlorine can cause a litany of issues as well.  First off, swimming in a pool or spa with no sanitizer is quite dangerous!  There are all sorts of water borne illnesses one can pick up.  Algae is another annoying, and costly, occurrence that can occur if there is not enough chlorine in the water.  We are shooting for that ideal range of 2-5 parts per million (PPM).  

Too Low of a Calcium Level

If your pool’s water has a level below 200 ppm of calcium then the water will seek it out.  It searches our equipment, our plumbing, and even our bodies!  It leaches and can cause severe damage.  Calcium does not evaporate, so be careful not to add too much as we do not want too much calcium either.

Too Much Calcium

Too much calcium, over 400 ppm, and you may see some scaling around your swimming pool and even on your equipment.  This is made worse by unbalanced pH and alkalinity.  We ideally want our water’s calcium somewhere between 200-400 ppm.

Unbalanced pH & Alkalinity

Too low of pH and/or alkalinity can cause your swimming pool’s water to become corrosive.  The water is then damaging to the vessel, plumbing and equipment.  It also makes the sanitizer less effective.

Too high of pH and/or alkalinity and your water may become scale-forming.  This leaves that unsightly white build-up along your water line.  Guess where else that is happening?  If you said plumbing and equipment…you are correct!  It can gunk up plumbing, making circulation more difficult.  It can build up on equipment causing it to have all sorts of different damage.  Sanitizer is also less effective if our pH/alkalinity gets too high.


Metals can be naturally occurring in water.  Some is ok.  Typically less than 0.2 ppm.  We must be aware of excess copper, iron and magnesium.  If you find your metal levels too high, you will want to use a chelating agent to gather them into the filter and then proceed to do a filter clean.  Metal-removing products only work with certain limits of high levels.  If your levels are too high, you may need to drain your pool.


Leaves and other organic debris can cause your phosphate level to rise.  Phosphates are food for algae.  We don’t want a Las Vegas Buffet laid out of phosphates, especially if we have trouble with algae.  Using a phosphate reduction product is a prudent insurance policy to any pool in danger of getting algae.

Organic material is not only unsightly but can cause staining.  These stains can be hard to remove and may end up requiring you to purchase a stain and scale remover.  Remove debris out of your pool as quickly as possible to avoid these risks.


Even a small leak at your pump, filter or heater is no bueno.  It can ruin whatever piece of equipment that is leaking.  Since your swimming pool system is designed to be an airtight system so we want to repair leaks as soon as possible.  

I hope this was helpful in educating you on some of the damage that can occur in our pools if we are not diligent.  See you poolside!