If your pool has gone green all of a sudden, or if you have just arrived back from a break away and you noticed your pool is turning green don’t panic. Algae is a very common problem in pools. It can occur if your pump is broken, your filter is clogged or your chlorinator ran empty.
Once algae sets in it will continually grow until all of it is eliminated. You need to nuke it with chlorine (free chlorine) until ALL of it is gone. If you stop halfway and go back to your pool in the morning more of it will grow back and you will have wasted your time, chemicals and money. This process is called SLAM (shock, level and maintain).
The amount of chlorine you will need to shock your pool with depends on the CYA (stabilizer) level your pool is currently at. If it’s high you will need to add more chlorine. Add too much and you can damage your pool surface and equipment, add too low and you won’t get rid of the algae.
You need a test kit to check CYA levels. Here are 2 videos that walks you through the entire process of shocking your pool and the begins with a K-2006 test kit, and then the shock process. It’s extremely easy to follow along too.
Here’s an explanation on how to use the Taylor K-2006 test kit.
When Is it A Good Time To Test Your Pool Chemistry?
Well ideally when setting your chlorine levels for the first time, or after you have noticed a problem with your pool you should test them everyday for a week. Then once a week is fine if you are really confident you can notice changes in your water and if there has been no radical weather changes.
You are trying to achieve a “balanced” pool, so the water does not become corrosive to the skin, or under treated so it becomes a breeding ground for bacteria. Balanced pools have the right PH levels, + correct TA (total alkalinity) and Calcium Hardness levels.
In order words it’s about getting the right chemical balance in your pool by, no pun intended – adding chemicals. Add too much of one and it effects the other. The environment, dirt and pollutants also effect all these levels in your pool.
The filter will remove dirt from your pool and the pump will circulate it into your debris baskets. A robotic pool cleaner will scrub dirt away and vacuum your pool. But the correct sanitation levels must be set by adding chemical content to your water.
After heavy rain you should test chlorine levels or if your pool is getting a lot of activity, say an all night party or a kids birthday party, you should check levels just to be on the safe side. Check your pump and filter once a week to make sure nothing is clogged up and they are working correctly.
If you notice your filter is clogged then it would be a good time to check levels as it may not have been doing it’s job properly. Better to be safe than sorry.
It also depends what you are testing for. If your PH levels stay mostly the same throughout the summer season once or twice a week is fine. CYA levels once stabilized and you know what you are doing can be tested every 2 weeks. TA (total alkalinity) levels should be tested every 1-2 weeks.
The Measuring Process Explained
Ph levels– checks how acidic your water is. Ideally should be kept between 7.2-7.8. Anything below is referred to as CORROSIVE and will damage your pool, including heating elements inside your equipment and the plaster. Anything above is consider BASIC and will leave calcium deposits and scale around your pool and can turn the water scaly.
Adding base will increase ph levels and adding acid with lower ph levels. It’s a scientific matter bring ph into an acceptable range, that’s why you MUST TEST.
Total Alkalinity– similar to ph, is a complex measurement of components, which in a nutshell is measurement of how resistant water is to ph changes. Alkalinity stops ph levels radically bouncing up and down. When it is low you add base, high you add acid.
Ideal TA readings depend on pool type:
Gunite & Concrete Pools: 80-120ppm
Painted, fibreglass, Vinyl Pools: 125-170ppm
Calcium Hardness– this has a direct relationship with TA levels and is is a byproduct the solutions put into your pool which can cause calcium deposits around surfaces. When referring to calcium hardness tests, you are actually testing how “hard” or “soft” the water is.
Hard water is more prone to have high calcium and magnesium levels, soft the opposite. You will notice white clumps around steps, ladders and lights if this is the case. Is “soft” water a problem? Yes as it causes problems with pool plaster as it contains calcium, it can actually start to corrode plaster surfaces around the pool.
One Test To Rule Them All (Sometimes…)
There is a test called the Saturation test or Langelier Index which uses an equation for all these levels that recommends the correct mixture of all the chemicals you need to add to your water.
It gives recommendations based on a chart but sometimes these are a little off and don’t take individual factors into consideration that may have caused a spike in one of your levels. It is a good indicator about the general state of your water though, helpful for diagnosing a quick fix possibly.