Chlorine

[Lpv77]

I have a caldera with a swg system. I had issues in the past with chlorine demand I checked up to not flushing the new tub. I've since fucshed and changed the water and its been so much easier to maintain.
I had some people in it last weekend and decided to shock it as a precaution with non chlorine shock. I opened the tub this am to test it and notice a tiny bit of scum at the water line, the tub is ever so slightly cloudy and it had zero chlorine in it.
Could the addition of the non chlorine shock screwed everything up?
I lowered ph and added .3 oz of dichlor this AM.
We have company coming over and wanted to use it tonight. I have it running now to see if it'll cleat up a bit and will check chlorine in an hour or so again.
Any other suggestions?

 

[Ahhsomeguy]

Lpv77: You should be good to go for tonight’s soak. Just be sure that you have a decent reading of free chlorine, generally 2-5 ppm. The scum you see is probably normal. Just wipe it away with a microfiber cloth when you see it. It may be remnants of what was in the plumbing when you flushed the tub. Your water should clear up this afternoon if the pH is in range and your di-chlor is still in the water. Enjoy.

 

[Lpv77]

Lpv77: You should be good to go for tonight’s soak. Just be sure that you have a decent reading of free chlorine, generally 2-5 ppm. The scum you see is probably normal. Just wipe it away with a microfiber cloth when you see it. It may be remnants of what was in the plumbing when you flushed the tub. Your water should clear up this afternoon if the pH is in range and your di-chlor is still in the water. Enjoy.

I just tested it again and fc is 2.5 and 0 for cc. Ph is perfect I flushed it several weeks ago and it hasn't had anything up until I shocked it. Was the first time I shocked it since I flushed it.
I think it'll be fine as well. I'll put it on boost mode later

 

[Ahhsomeguy]

If you are planning 3 or 4 adults in the tub tonight I would probably add a level tablespoon of di-chlor around 5 tonight and possibly another 1/2 level tablespoon around 8 tonight. You will be well protected. Keep the tub running so the filter is operational. Water should be great by 5 tonight.

 

[VinnyinNJ]

Don't use non chlorine shock! I have used it but it really is not a good thing. Since you have a SWG in a spa I'm not sure if you need CYA or not as chlorine can be a little aggressive if you have 0 CYA. SWG in a tub is new to me. What Ahhsomeguy said is true, bring chlorine up before and be prepared to add somewhere during the night and make sure you run all the pumps and jets to distribute the chlorine anywhere there is water. After the party, shock it with chlorine running the pumps, leave the cover open for 20 minutes for the off gassing and you should be good to go. I used to shock to 6 PPM in a tub as bacteria is more fragile than algae but high CYA can inactivate the chlorine and you'll need more..

 

[phonedave]

Non chlorine shock is not a sanitizer, it is an oxidizer. Oxidization is breaking down stuff like oils and other stuff that makes your water murky. It does nothing for bacteria or algae. You need chlorine to combat those.

So by adding non chlorine shock after your party you burned off the sweat and skin oils, but did nothing to the load of bacteria that was introduced to your hot tub.

As an aside, some people are allergic to MPS (non chlorine shock) and get a pretty bad skin rash. I myself don't use it.

 

[darkrider]

Agreed. Don't use the non-chlorine based shock. If you can get your CYA level to about 35 (maybe higher if you have direct sun exposure), your SWG should do a good job of keeping up with demand. After a fresh fill in my HotSpring Grandee w/SWG, I generally use Dichlor as well to get the CYA levels up while augmenting the SWG production. However, once I hit my target CYA level, my FC stays at about 3ppm. At that point, if I need to shock (rarely) or augment the SWG production, I use liquid chlorine. Otherwise, the only adjustment I really have to make is to lower pH maybe once a month. Once I start to see some registered CC, I go ahead and change the water. That happens for me right around the 8 month mark.