Why do swimming pools turn green? What makes a swimming go green in colour

If you are a swimming pool owner, and have had your pool for a long time, you might be familiar with green swimming pool syndrome, and how to fix it.

 But if not, and you are new to owning pools and all of the joys of pool maintenance this post, drawn from personal experience may be of help.

 When it comes to private swimming pools, perhaps a backyard pool, above ground, in ground or otherwise, there are two main sorts. These are chlorine pools and salt water chlorinated pools.

 The aim of both systems is the same, to keep the water clean and safe to swim in. By safe, we mean keeping bacteria and algae at a non hazardous level.

 The owner of a chlorine pool does this by putting a measured amount of chlorine in the pol and checking it. How much goes in depends on the size of the pool and the weather Hot weather and sun will cause the chlorine to break down quicker. Evaporation and rain will also affect the chlorine balance of a pool. A salt water chlorinated pool still uses chlorine, but it does so by converting normal salt to chlorine.

 When not enough chlorine is present in the pool, algae and bacteria will begin to multiply. They do this causing the water to go hazy. This is a warning sign. If your pool starts to appear hazy, you be to either add chlorine or run your salt converter. At this stage your pool is not clean enough to swim in safely.

Swimming in a green pool runs the risk of ski irritation ad bacterial infections. If there is not enough free salt in the pool, the electrolytic converter will not have enough salt to convert to chlorine, so you will need to add salt first.

 If you don't do this, the growth of algae and bacteria increases exponentially, and large clumps of algae will start to form. It is this green algae that gives the pool the green look. By now, if you have a salt water pool it is now too far gone to recover using just the pools chlorinator. When a pool is clear and safe the salt water chlorine converter will make enough chlorine to keep things healthy but once the algae growth has rocketed most chlorinators will not make enough to reverse the situation.

You will need to shock treat your pool with a high dose of chlorine and algicide. I have covered that in another post here.