First post here, but I've been lurking and learning for a while. I realize this is probably just a variant of the old "how much chlorine do I need to oxidize a dead porcupine" question, but it's new to me anyways.
Running a wood-heated hot tub, using dichlor/bleach for sanitizing. CYA around 25-30 using a Taylor kit, just on the cusp of switching to bleach after the most recent refill. Everything seemed to be fine until the last couple of days, when a thermometer failure resulted in the water getting hotter than planned, so I closed the air intake with the fire still burning rather than letting the fire burn down normally. The Snorkel chimney is arranged to keep rainwater from running into the stove, but the downside is that if you do make a lot of creosote some of it can drip into the water. Normally I burn hot fires and creosote isn't a problem, but damping the fire down mid-burn made a lot more creosote than normal.
I added about 8 oz of bleach after using the tub last night, which is normally enough to give me a few ppm of FC the next evening, but when I checked this morning the chlorine level was 0. Added another 6 oz bleach, checked chlorine level after mixing, then re-checked a couple of hours later -- 0 again. Added 4 tsp of dichlor and checked chlorine level immediately after mixing it in -- 5-10 ppm, no problem. Will check FC/CC as soon as I get home.
I gather from this that chlorine probably does try to oxidise creosote and that's why my chlorine is suddenly disappearing -- guess I'm wondering if MPS might be a better choice or if there is some other magical "creosote-B-gone" chemical I haven't heard of.
Normally I can follow the "when in doubt, drain it out" method but we've been having a lot more snow & ice than usual and it took about 200 gallons of hot water to melt down to the drain plug last time
Thanks in advance...