Swimming pool sanitation and paint are both called on far too often to cover a multitude of sins. While it might not be as devious as lining your leaking roof gutters with newspaper and spraying them black (when trying to sell your house), pool sanitation is called on to cover short comings such as,
The point is that the sanitation required in theory and the sanitation required in practice are two different things. Any sanitation system installed must take that into account. Even the most diligent of operations have things go wrong and it’s the speed at which wrongs can be fixed that’s important. Fixed, that is, before it starts to cost you serious money in chemicals, labour and power or before you lose customers.
We need a sanitation system that will keep your chlorine levels within an acceptable range but not below the required minimum level throughout your trading period. On top of this we need a dosing system that will respond to unforeseen events and any operational inefficiencies.
With a liquid chlorine pool the rate of dosing comes down to the size of the chemical pump. Years ago, I put a new chemical pump on a school pool’s liquid chlorine delivery. I pinched the sizing from an engineer’s specification for a similar pool. Immediately there was a huge improvement in ‘setpoint’ recovery. Turns out that the new pump was considerably bigger than the replaced device. You have to be lucky sometimes, don't you Fred.
How did I know?
The chemical controller was an Aquarius Ultima Basic model with web connection. I could see the changes in the dosing graphs. There wasn’t much change it the curve above the set point line, but there was a big change in the curve below the set point line. The negative amplitude was almost halved. The recovery was much faster. That’s the key to good dosing. The quicker the recovery the better. Truth is, we would not have known that the pump was bigger, if it had not been for the controller.
The only way you truly know what is going on with your chemical dosing is to have a chemical controller that shows you what is happening. Without the Ultima controller we would never have known the effect the bigger pump had on sanitation improvement. The pool still looked the same (when we saw it once a week) but with the higher recovery dosing there was less chance of problems developing.
If you are considering converting your pool over to a saltwater pool and installing a commercial saltwater chlorinator then you will need to know your existing dosing data. An Aquarius Ultima can give you that information. Knowing your total consumption does not give you enough information. You need to know what your peak rate of dosing is and that’s assuming your chemical pump is big enough.
I downloaded the data from two pools where I know that one pool (Site A) has much better dosing than the other (Site B). The load on both pools is similar. The idea here is to give you an idea of the information you can get from an Aquarius Ultima and the type of information that might be helpful in choosing the right path to follow.
The most important thing to see here is that the smaller pool with an output nearly the same as the larger pool did not struggle. Look at the difference between the dosing rates throughout the day. The set points differ between the pools. All pools are different in that regard. Site A dosing is controlled by the ORP probe while the dosing on Site B is controlled by a FAC Membrane probe.
The data that you can download is enough information for you to be able to do further calculations as you see fit, in order for you to gain the information you need on which to base operational decisions. The table above is just an example of 'let's see what this calculation tells us'.
The following are the Aquarius Ultima Charts for the same day.
Looking at the blue lines you can see the Site B chlorinator is running at 100% throughout the day while the Site A chlorinator only touches 100% twice briefly. As stated above the Site A pool has far better sanitation control thanks to the size of the chlorinator for the volume of the pool. Both of these pools do not have a lot of use compared to other commercial pools.
When considering converting a pool from a Liquid Chlorine pool to a Saltwater Pool you should look at the dosing rate that is needed based on its history and the size of the chemical pump. Site B would most likely have a 12 liter per hour pump if operating as a Liquid Chlorine pool which would respond quickly to any sudden drops in chlorine. The chlorinators above are only able to deliver 3 to 4 litres of equivalent liquid chlorine per hour at most, and never at a higher rate. It is critical to understand how important this information is when choosing a saltwater chlorinator. Chlorinators are an expensive investment. You want your operation to improve, not go backwards, don't you Fred. The alternative is to believe what a sales rep tells you.
An Aquarius Ultima Controller has a B dosing system which gives you back up dosing (which is usually liquid chlorine) when the read drops below a secondary, lower set point. The right balance between the size of your chlorinator/s and liquid chlorine backup is worth serious consideration. The liquid chlorine comes into action during those periods of sudden and possibly unexpected demand.
I wish to hell I had access to this sort of data several years ago. I received a specification to quote the installation of chlorinators. I could see straight away that they were going to be far too small. The bloke issuing the specification had absolutely no idea what he was talking about. Not a clue. The only weapon I had was experience, nothing solid. I chose not to quote as I could see it was going to be a disaster. In the end I heard that they did go for larger chlorinators, but even then, I didn't think they were anywhere near big enough knowing the demands that were going to be put on the pool sanitation.
