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How to accelerate chlorine recovery after purging with SC-1000

The SC-1000 purge dose can wipe out free chlorine levels. Here's how to speed up the recovery process.

The SC-1000 purge dose will be attacked by chlorine until it has had time to find metals and minerals to bind to (chelate). Until SC-1000 has bound up those metals, chlorine continues to try to oxidize it.  SC-1000 is immune to chlorine oxidation, however. So the result is zero chlorine for several days, and it's frustrating for pool owners and pros alike. We get it. The long-term benefits of SC-1000 are substantial, so it's important to navigate the initial dosing correctly.

How to recover chlorine levels after the SC-1000 purge dose

SC-1000 (1)

The fastest way(s) to recover free chlorine levels is a combination of the following:

  • Pre-dissolve calcium chloride and add it to the pool.
    • Most pools should have at least 300 ppm calcium hardness. If you have less than 300, this is a great opportunity to increase calcium while also giving SC-1000 something to do in the water.  Colder climates (like the US northeast and midwest) can benefit from over 400 ppm calcium. It just depends on how these levels impact your LSI balance.
  • Reduce the pH with diluted acid without creating a low LSI violation.
    • Use the Orenda Calculator™ to determine how low you can drop your pH in the water without the LSI dipping below -0.30 and turning red. Maybe its 7.6 for you, or maybe its 7.7.  Whatever it is, use the prescribed amount of acid and dilute it thoroughly before pouring it into the pool around the perimeter of the deep end.  Lowering the pH can accelerate chelation.
  • Increase circulation time.
    • If your pool is not circulating 24/7, you can increase the run time. More circulation means more mixing in the water. This can help SC-1000 find the metals it's looking for.
  • Heat the water.
    • Chelation is a function of time and temperature. The colder the water, the slower it happens. And below about 60-65ºF, it may not happen until the water gets warm enough the next season. The warmer the water, the faster SC-1000 works.

What to do if too much SC-1000 was added?

If you add too much SC-1000 (more than the recommended purge), you can either add more calcium chloride to the water to give that additional SC-1000 something to bond with, or dilute some water from the pool.

We strongly recommend against purging at one time if you cannot afford 4 or 5 days of no chlorination.  This is why our purge instructions say to divide up the dose over several visits, OR purge in the spring when the water is warming up past 60ºF (and rising), so you can give it time to do its thing before needing chlorine. Chlorine becomes far more important above 65ºF as contaminants get introduced and try to multiply.

To reiterate, the chlorine is not holding after the SC-1000 purge because SC-1000 has not yet had time to do its job. Either give it more time, or accelerate its ability to finish the job.  

dissolve calcium chloride, how to add calcium

Adding calcium chloride is a great way to accelerate the recovery of chlorine for two reasons. First, dissolving calcium chloride creates heat, and when that warm calcium chloride slurry is added to the pool, it accelerates SC-1000's reaction speed in the immediate area. This is good. 

Second, the new calcium introduced is exactly what SC-1000 is looking for.

Hopefully you're able to recover the chlorine levels quickly. If you're struggling to hold chlorine past the 5th day, contact us.