With swimming pool season approaching it’s time for the posts to switch to pool information. The info I’m going to give in this post is about total alkalinity. Most of the new customers that come to my store are unaware that total alkalinity is something they should be testing in their pool and spa water. Most new customers are introduced to total alkalinity when they bring in a water sample to be tested.
Usually, they are having a problem keeping their PH in an acceptable range. The problem is that no matter how much PH up is added to the pool, the level always seems to be below. When I hear this the first thing I test is the total alkalinity of the water. What happens is the total alkalinity drops below the recommended level for their pool and this drags the PH level down also. You can adjust the Ph of your swimming pool to the correct level and within a day or two, it will drop back down if the total alkalinity of the water is too low.
Different types of swimming pool surfaces require different levels of total alkalinity. A vinyl liner swimming pool needs the water to have a total alkalinity level of 125. A concrete, gunite, or fiberglass pool (or hot tub) needs a total alkalinity level of only 80. It is extremely important to keep the total alkalinity at these levels. they can be a little higher than this but no lower.
If for example, the total alkalinity of a swimming pool is 200 my suggestion would be not to lower it. If you choose to lower the level it can be done by adding acid over the course of several days. It involves adding acid to lower the ph, waiting for 24hrs for it to come back up, retesting, adding more acid, waiting for 24hrs, retesting, and so on until the alkalinity is correct. By doing this most people bottom out their ph and alkalinity and have to add alkalinity increaser to raise everything back up. If this sounds like a lot of trouble and a waste of time that’s because it is. If the alkalinity is a little high, leave it alone. It won’t hurt anything.
If the alkalinity in your pool is too low raising it is as simple as adding alkalinity increaser. The instructions on the container will guide you on how much to add.
Some things that can cause a drop in alkalinity are rainwater entering the pool water and swimmers who don’t exit the water to go to the bathroom. Rain can be acidic and so is urine. I have some customers that are farmers and they have said that some of the fertilizers they use in their fields get airborne and lower the ph and alkalinity of their pool water.
No matter what lowered the alkalinity of the water it is important to maintain the correct levels for your pool. By not doing so your ph will always be below and this is hazardous to you and your swimming pool equipment. So remember to always check your ph weekly and if it’s low check the alkalinity of the water. It could be the reason that the ph won’t stay up.