10 Alkalinity and pH
This is Janine with Pool Zones and this is series 2, where I’m going to cover some details about ‘How difficult is it to maintain my own pool, how much chemicals should I add, when should I add, and what should I add?’.
You should have completed series one videos, and in series one, remember the sequence. As you can see here; in steps one through two step five, and today I will discuss adding chemicals to balance the alkalinity, and the pH, which we should know moves together, or are affected by the same chemical.
Another factor to consider is that all of the chemical bottles, all of the materials that you will purchase chemicals to add to the pool; the instructions or the numbers on them are calculated to 10,000 gallons of water, or an increment of 10,000.
So keep that in mind regarding this particular discussion. My numbers will be based on 10,000. Now, if your pool is 15,000 gallons more than 10,000 or 11,500 gallons, add 15% more to the 10k calculation.
So let’s look at that, in other words you know what you multiply by 1.15. Let’s say that if it is less than 10k, Say 8000 gallons then use point eight, multiplied by the 10k formula. So let’s take a look in here now in terms of how do we balance the alkalinity, and what do we need to add.
This is based on 10,000 gallons. So let’s say for a moment I’m going to skip from alkalinity into PH which is exactly what I told you not to do, but I will explain why in a few moments. And I’m sort of working in this manner and I’m still reverse engineering my way to alkalinity balance.
Let’s say that the pH is 7.8, and we want to reduce it to 7.2, so what do we add? We’re going to add three pounds of dry acid, which is also known as pH down or Ph decreaser, the chemical name is sodium bisulphate.
Now, or if you’re using Muriatic liquid, add 36 fluid ounces, so the ratio is either 3 pounds of dry or it’s 36 fluid ounces of Muriatic liquid.
So now let’s take a look into how to add the acid. We saw this video in the first series where I show that I’m using dry acid, and I prefer dried to liquid, because I just find that the liquid when I’m pouring it in, that I get a whiff of it and it’s a killer to just get wiff of the liquid so here I’m using dry acid, and in this case I am adding a little less than three pounds, because my numbers are slightly different.
I wear gloves because it does burn the skin, and I will even use a plastic bag just to protect my hands as an added layer. So I’m adding the acid, I’m measuring it in… you can see there I’m measuring, and then I take it to the pool, and I mix it in. So we’ll take a look at the mixing process here.
These are both dry acids, I buy in bulk as well so I put some in the bucket and I label the bucket. And now I’m going to stir it and add it to the skimmer. Now, again I’m going to balance the alkalinity and the pH at the same time.
Take a look here and sort of fast forward this because I’ve done this before you should see it you will notice that it needs to be gradually added. At three pounds for an 11,500 gallon pool that’s really a very low quantity of acid.
Now, why did I skip to pH let’s take a look at the reason behind that. In taking a look at that this shows me; this is actually a calculator online that you can get access to, it’s pooloperationmanagement.com. And this is a really wonderful calculator because I can put numbers in here, and then I can come and select over here what type of chemical I want to use, which in this case is dry acid, which is sodium bisulphate and don’t be concerned about the name, it’s very simple to pull it up.
And as you can see here, and in terms of my reading; my reading for pH was around eight. My alkalinity was around 200. Now an ideal alkalinity reading would be between 100 to 120 for example, or 140 for example, so you can see here that what I’m aiming at with alkalinity would actually take in terms of dry acid it would take around 13 pounds.
But coming down to the pH, the pH only requires four pounds so imagine this, say I went out there and I added 12 pounds of acid, which I would never do, my pH would drop so low, below 7.2 and we’ll take a look at what happens when we add, for example, 12 pounds of acid, so the only way I will actually get 12 pounds… reading this let’s put five in there, there you go. Let’s put 5.5 there you go.
So in other words, if I were to add 12 and a half pounds of dry acid to balance this very high alkalinity, to 140, to get it very close to where I wanted, the pH would go into the corrosive range, at 5.5 that would basically corrode the light because the light has metal around it, it would corrode parts in the heater, and it would corrode parts in the pump, so we never never want to do that, and so that’s why I’m explaining to you what I aim for is I’m going to aim for the 7.2 for the PH which will not give me 12 pounds, but what I’m going to do is I’m going to add that in, and it says four pounds but you know we’re going to add three.
So, I’m just giving you an example, and so what I’m going to do is I will be adding that today for tomorrow I’ll check it, and I’ll check the alkalinity which will have dropped, and then the following day I may repeat the same process.
Now I am talking about a new pool and a new pool will require a lot of dry acid or liquid acid, so keep in mind, I’m going to gradually work on alkalinity, not directly, but I’m actually going to work on it by working on pH, and as you know, when we work on one, we work on the other as well.
So, that’s how you balance alkalinity, you do it by balancing the pH and continue to work on the pH, and you will balance the alkalinity. Now there’s one caveat to that, which now sounds like I’m going to totally throw things out of whack.
At some point the alkalinity is going to continue to drop, and continue to drop and continue to drop, to the point where when you check it, you’re going to see something like… let’s cut out of here, we are not going to need any bisulphate, we don’t need anything actually.
We’re going to have to increase so we have a reading of 16 for example, so it’s dropped way way down. And we’re going to need a carbonate, in this case. Now, just disregard this at the moment, we’re not interested in that factor right now, I’m only letting you know that in a subsequent video, I’m going to show you that this will just continue to drop, and drop, and drop to a very low level out of the ideal range, and then we’re going to want to increase this later, much later on.
So at this point, we’re just going to work with the sodium bisulphate, to help decrease the pH, and then when we start seeing a crazy low reading on alkalinity, anything below say 80, then we’re going to start looking at adding sodium bicarbonate, to bring this back up.
So, today’s lesson is on balancing alkalinity and on balancing pH, and I think I’ve explained that process to you. If you’d like to know more, then let’s go to the next video in the series.