In this Article, I will discuss 5 major reasons why your swimming pool in Lagos will turn green.

  1. Mechanical Issue with the pump, Pipes or Filtration system
  2. Imbalanced chemical composition of the water that made it easy for algae to thrive.
  3. Oxidized Iron content in the freshly introduced pool water
  4. Oxidized Iron content from dissolved gasses through Rain
  5. Frequent addition of fresh water to the pool as a result of pool leakage

 Swimming Pool Chemicals

Mechanical Issue With The Pump, Pipes Or Filtration System

In order to fix the green pool, we need to first check if the filtration system is working optimally. We need to check the water pressure in the filtration tank, we need to check the quality of the sand in the sand filter or the cartridge if you are using a cartridge filter. If any of the filtration media is blocked with dirt, then the filtration has been working sub-optimally. Once this is cleared, we proceed to test number 2.

Imbalanced Chemical Composition Of The Water

Every swimming pool where you have swimming lessons in Lagos, the owner of the pool administrator should have a pool test kit. It is foolhardy not to have one at a swimming pool. First, we test for the Alkalinity of the water, we test for the PH of the pool, we check the chlorine content and lastly we check for the calcium content. The readings help determine which chemical component became skewed that allowed the growth of algae in the water.

If the PH level is too high, we apply PH minus and if otherwise too low, we apply PH plus to the swimming pool water. The optimum PH Level should be 7.2

At a PH of 7.2, chlorine works best and indeed since the human eye has a PH of 7.2, the pool will never irritate the eye at that level. (At least to correct a lot of Nigerians that believe that the high amount of chlorine is the reason why a swimming pool is peppery on the eye)

Notably, after this test results are obtained; the first thing you want to do will be to dilute the pool water first, this gives you a quick win almost immediately.

Oxidized Iron Content In The Freshly Introduced Pool Water

This is by far the most common cause of green swimming pools in lagos. In many areas of Lagos state and indeed all around Nigeria. The water that we drink and also bath with contains a high amount of Ferrous (Iron). Once the water containing iron is introduced into the swimming pool, it immediately reacts with the chlorine in the swimming pool water. This forms Ferrous Oxide, which is either dark brown in color or mostly greenish in color. This is the major issue with many swimming pools in Lagos. The reason why most pool owners introduce new water into the pool is due largely to the fact that the pools are leaking. Once a swimming pool is leaking; its doom and gloom, since you have to always introduce new water, which is already leaden with iron that causes the water to turn green and in some cases brown.

If you have a case of oxidized water, then you need to sacrifice 4 days of constant filtration, backwashing, vacuuming and more vacuuming to waste as the Ferrous oxide will settle at the bottom of the swimming pool and a slug. Which will take days to clear out. As you clear some that had sediment at the bottom, more will sediment again over night. You will continue this battle for 4 days.

At the end of the 4th day, the swimming pool will be sparkling clean. But the problem is this, your pool is still leaking. Meaning that you need to introduce fresh water in another couple of days, which will turn the water bad again. It becomes a vicious cycle. So the only solution that this sort of problem require would be a complete overhaul of the swimming pool. We need to detect for leaks and get it fixed. Once this is fixed, we are home and dry. Rain water also fall under the same problem.