When do you use MPS?

[amattas]

What are scenarios where you'd to use MPS to augment your regular bleach sanitize / slam process?

The pool store tried to convince me that using Sodium Hypo in the hot tub was bad over time because it adds salt to the water, but the truth of the matter is MPS breaks down into a salt as well, so I see no real benefit in using it for what the extra cost is.

Another pool owner I know suggested using it when the pool was under heavy load (hence the reason I'm asking, I have a pool part in a few weeks with 18 kindergarten kids and their parents). I plan on giving it bumps with bleach throughout the day, and potentially augmenting with tricolor sticks. But when everyone gets out for lunch should I hit it hard with the bleach or toss in some MPS?

 

[mknauss]

Is this a hot tub/spa or pool?

 

[amattas]

Is this a hot tub/spa or pool?

I have both.

 

[Donldson]

Pool - never. With the volume of water even a bunch of kindergartners can be handled with bleach. Wouldn't even bother augmenting with trichlor, they release chlorine so slowly as to be completely useless for a single event. Just bring the FC up, as high as SLAM level (still less harsh than a pool with 2 FC and 0 CYA) and check it every couple of hours. Virtually never a need for supplemental oxidation.

Spa - occasionally with heavy use. It is a much smaller vessel so the bather waste concentration is way higher than the pool. The additional oxidation can be of some use in this case.