MSI: One very dynamic pool chemical
Meaningful pool care in more ways than one
Think of the most dynamic pool chemical you know of. What does it do? When we think of the word “dynamic”, it suggests multiple uses and a range of positive results. Metal & Scale Inhibitor (MSI), to us, is one very dynamic pool chemical. It serves many functions, including the ability to both prevent and undo common problems in swimming pools and other water treatment systems. Let’s share some of them.
1. Preventative water chemistry
Water chemistry affects everything in a water system. If your water is corrosive, it can cause damage to surfaces and equipment. Conversely, if it is scale-forming, the scale itself can cause damage too; pipes with scale in them can increase water pressure and reduce flow rates.
The most important factor in preventing corrosion and scale is LSI balance. After that, it helps to have a chelant like MSI to hold minerals and metals in solution. Take calcium carbonate scale, for example. If calcium is held in solution by MSI, it takes a much more for scale to form. Think of MSI as allowing more grace to your water chemistry.
It’s not that MSI prevents these problems from happening…it’s that it gives you, as an operator, an advantage in handling minerals and metals.
2. Protecting pool plaster
Pool plaster is most vulnerable while it is curing. Plaster curing can take 30 days more more while the surface hydrates underwater and hardens. Given that calcium chloride is often used as an accelerant in plaster mix, it provides available calcium to water that is probably calcium-deficient. Water will stop at nothing to reach equilibrium. As the universal solvent, water dissolves whatever calcium it can find and bring it into solution for its own benefit; the most readily available source is plaster or tile grout.
But what about vinyl liner pools, or fiberglass? The LSI still applies, but the difference is water has no source of calcium. Therefore, low LSI water corrodes its way through everything trying to find it. The damage can be severe over time. For vinyl liners, this can mean fading, wrinkling or even wearing through the liner itself, allowing water underneath it. It’s no good.
MSI provides more grace to the LSI. In effect, it seems to buffer the LSI acceptable range, making it more difficult to form scale, and more difficult to corrode. Of course, this buffering benefit has its limits. At some point, the LSI can be so far out of range that no amount of MSI can stop the inevitable consequences. Use MSI immediately upon filling (and refilling) a swimming pool. It gives you more time to adjust the chemistry to get in proper LSI range.
With any sequestering agent or chelant, one of two things happens: it gets oxidized by chlorine, or it wipes out chlorine. MSI’s initial “purge” dose wipes out chlorine. In most cases, this is an annoyance; chlorine must be hand-fed for two or three days to catch up, because otherwise the pool is unsafe. Fortunately, the weekly maintenance dose of MSI is small enough that it hardly has any impact on chlorine levels. More importantly, the good news about MSI is it will not be oxidized out of the water by chlorine. That means it stays in the water and works to your benefit over a longer period of time. It’s just the initial concentration of the purge dose of MSI that overpowers chlorine…and when dosed properly and evenly circulated throughout the pool, chlorine levels can maintain just fine.
Dechlorination is sometimes needed, however. For example, if you need to do certain types of maintenance, or bring chlorine levels down from recent hyperchlorination, MSI can help. Rather than using sodium thiosulfate, MSI can accomplish more than just lower chlorine. After all, you get the benefits of this dynamic pool chemical while lowering the chlorine level to where you want it.
Realistically, dechlorination is a rare need for swimming pools…but sometimes it’s urgent. MSI can drop chlorine levels down in just minutes.
4. Chelating Metals, Preventing Stains
Metals are the first substances to be oxidized when chlorine enters the water. Oxidation can change the color of certain metals. Eventually, when the water is oversaturated with dissolved metals, or when they are oxidized, they can fall out of solution and stain. Just like with calcium saturation, water can only hold so much.
Stains come in many different colors, and there are entire businesses devoted to stain removal. We are not one of them…but again, MSI is a dynamic pool chemical. Just like with calcium, MSI gives more grace to the water’s ability to hold metals in solution. With MSI in your water, metals have a far more difficult time coming out of solution and staining, because the metals are chelated.
Chelating metals means MSI isolates each metal ion and binds with them. Binding with metal ions prevents them from being oxidized.
Can MSI remove existing metal stains?
Over time, MSI has shown it can gently dissolve stained metals back into solution and lift them from the pool surface. We told you MSI is a dynamic pool chemical. Unlike acid-based products, however, this process is slow. You may want to combine its efforts with ascorbic acid (vitamin C) to speed up the process. That said, be sure that the stain in question is, in fact, caused by metals in the water. Some stains come from behind the pool surface itself, like rebar being too close to the surface. In those cases, MSI cannot prevent or permanently remove that problem.
5. Scale removal
Yes, just like removing stains, MSI can dissolve calcium back into solution as well. Of course, the long-term solution is LSI balanced water…but even then, hardened scale won’t move easily. MSI is the chemical to soften and remove scale deposits around your pool. It can even remove scale on spillways and water falls, as long as the MSI-treated water has time to affect the scale area. Raise your water level to remove scale on a tile line, for example.
Why use one dynamic pool chemical vs. multiple single-use chemicals?