lagreca Posted June 9, 2014 Report Share Posted June 9, 2014 I'm planning on leaving for a one week vacation, and am trying to figure out how to leave my spa... Since I have an ozone generator installed, I think I'll adjust the ph to 7.4, shock the spa to 20 ppm chlorine, once sufficiently mixed in the water, turn the breaker off to the spa and seal the lid. This will keep contaminants out, lower the temperature, and prevent the ozone from oxidizing the chlorine. Does anyone see a problem with this plan? Quote Link to comment Share on other sites More sharing options...
chem geek Posted June 9, 2014 Report Share Posted June 9, 2014 That should work though you probably won't need the chlorine to be that high. With no ozonator you shouldn't be losing more than 25% of the FC per day and that's at hot spa temps. With the water temp lower, you'll likely lose 15% or less of the FC per day. So starting out at 20 ppm FC would end up at 6.4 while starting out at 10 ppm FC would end up at 3.2 ppm FC. It's not a big problem if you want to play it safe and use 20, but measure the chlorine when you get back so you can get an idea of the chlorine loss rate for this situation -- let us know as well. All of the above presumes you've got 30-40 ppm CYA in the water already. Quote Link to comment Share on other sites More sharing options...
Spanky Posted June 10, 2014 Report Share Posted June 10, 2014 A well insulated spa, left in the summer sun, may not drop much in temperature. I've seen mine actually go up 2 deg on a hot summer day. I don't know if I would shut down the power as you would loose circulation. Personally l would prefer to keep the filters working. The ozonator is a different story. With bromine you want the ozone ON and with chlorine you want it OFF. There's 2 ways of doing that, 1) You can access the low level programming and set the ozonator to off 2) Most ozonators connect to the spa pac with a j&j mini plug. Just unplug it I've left a bromine spa for 2 weeks by loading the floater full, turning the temp down as low as the controller let me and using the low level program to set the ozone to "Always on" (for chlorine you would do the opposite, set it to "off") Another reason to keep the pumps running is that as the FC drops so will the pH. Maintaining the pump filter and purge cycles will provide aeration which will counteract the net acidity of the chlorine. It also doesn't hurt to boost your TA before you leave, you can always lower it (if it's still high) when you return. Quote Link to comment Share on other sites More sharing options...
lagreca Posted June 22, 2014 Author Report Share Posted June 22, 2014 I came back and tested the water.....I was at 0 ppm chlorine and at 80 degrees temperature, down from the normal 101. I just put in 3.5 teaspoons of Ahh Some spa cleaner, and am now going through the decontamination procedure, as there was a probably a biofilm in my spa. Quote Link to comment Share on other sites More sharing options...
chem geek Posted June 23, 2014 Report Share Posted June 23, 2014 I'm sorry to hear that. Are you sure you had the ozonator turned off? Maybe you had a buildup of leftover bather waste so had higher chlorine demand. If you started out with 20 ppm FC then to get to 0 (<= 0.5 ppm if you are using a FAS-DPD test), then the daily loss would be 23% per day. So maybe the temperature starting out high had higher loss. Anyway, the Ahh-Some should take care of any biofilms that may have developed. It's possible the chlorine only get that low in the few days before you got back, but bacteria do multiply quickly. If the water was clear and not cloudy and if the spa surfaces were not slimy then you probably didn't get much bacterial growth. Quote Link to comment Share on other sites More sharing options...
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