turbulentwaters

Yeah, I cleaned out the old store's supplies when I found out they were closing. Almost out now. I once titrated a sample and it was more like 7.5% instead of 10%, but I think it had been sitting on the shelf for a while before I bought it.

I'm very happy with the "dichlor then bleach" method and have been using HTH 10% liquid chlorinator for a while. Problem is my local hardware store that carried it closed down and I can't find liquid chlorine anywhere. Pool stores don't have it. All the big box stores list it on their websites but it's not in stock. Where is the best source of gallon jugs of ~10% liquid pool chlorine? I'll be using Chlorox 7.5% disinfecting bleach unless I can find some, but twice the price per Cl (not that it's super expensive in the first place, but still) and I'm not sure if it has additives. Thanks!

Thanks for sharing about the raspipool project. I'm also interested in automation and I had found a commercial option but have not used yet: https://www.hannainst.com/pool-line-ph-orp-controller-bl122-bl123.html. It's probably more difficult to make a clean installation of an automated system on a portable hot tub though due to space under the hood. You should search this forum for "dichlor then bleach" method of sanitation and you'll get a lot more info on using liquid chlorine in hot tubs. I find it makes for very clean water and highly customizable for the bather load. You can initially dose your hot tub with NaBr ("bromine booster") at startup if you want to run "bromine". The bromide salt will be converted to active bromine upon addition of bleach or pool chlorine of any source. Ozone might obviate the need for going bromine since I believe nasty chloramines are burned away without shocking (pH must also be maintained in a stricter range with chlorine). Also search for borax use. Helps buffer pH, maintain TA, and reduces the frequency of acid additions for me. It is tricky to prep though. Must mix in a bucket and then adjust pH to 7 using acid before putting in hot tub.

Hope you all had some success with the leakstop at this point. I called Marlig and they recommended leaving the tub drained for a couple weeks (!) to allow curing. Makes sense since the slicates (listed on MSDS) would need to dehydrate to form hard seals and I have a foam-filled tub where air can't get to. I'm just not that patient though and after a 2-day hold, I refilled immediately after draining. Seemed to stop the leak for the first week, but it's now seeping again. Maybe next time in the heat of summer I will blow out the pipes with a shop vac, maybe even leave the air blow running for a while, and let it sit for a day or two. Anyone make an epoxy-based or similar leak-stop product that will cure under water?

Still no real determination of the cause, but I did notice this odor again starting a few days after my refill three weeks ago. I did start up using dichlor again but just for a couple days and as I ramped up doses after bathing, I noticed that odor come back. I changed over to bleach and the smell has pretty much gone away.

Yeah, agreed. Honestly, I see no reason to not allow low speed pumps to continue to run. Check this thread above for the method (similar to Marlig's own recommendation if not draining).

On their website (http://www.fixaleak.com/hot-tubs-spas): "Recirculate continuously for 6-8 hours then shut system off...Allow 48 hours before resuming operation". Just turn off circuit breaker. I also already turned off the heater as a precaution, but I'm not sure if that is an issue. I'm assuming that this hold time allows some curing to take place, although their talk about foam-insulated tubs being waterlogged and inhibiting curing contradicts the usefulness of that. Maybe the curing happens when exposed to air on the outside of the leak (water evaporates from drips and the silicate salts form silica gel that binds the cellulose), but not likely if waterlogged foam is on the other side, which is likely why they recommend leave sitting if drained. Doesn't say draining/sitting is required though for foam. I'm just going to try @Cusser's method first. My leak is a few gallons a week right now and I have no idea where from, but seems worse when jets are used a lot. It's freeze damage for sure and I've fixed proper all leaks in the equipment bay already. It sat drained (but not winterized) through a whole winter before I got it. Cross my fingers! I think it will be easy to just hose the stuff down the drain, or just let it get collected by filter element if not based on how easily it is resuspended.

Just got back from the tub after forgetting to restart the jets for about an hour and I did actually now see a lot of the product had fallen out as a gel-like sediment, so that's good to know. Stirred up easily by just the jets. @mscdman, thanks for sharing. I did read in their instructions that I should let the tub sit for a while to allow curing upon draining (mostly pertaining to waterlogged foam-insulated tubs I interpreted), on top of the 48h hold after application. I really don't want to wait a couple weeks though as I've become addicted to bathing. I may try using the shop vac in reverse to gently blow out all the jet plumbing and hopefully hasten the curing while it's empty. How can you put this stuff in at startup? It would certainly be picked up by the filter element and leak-stop that!

Hah! Very good. I'm doing the same procedure today prior to a water change. I had imagined this stuff as dense blue globs that would quickly settle out, but it seems this stuff (light-straw colored thick liquid) just dispersed immediately in the water stream. Came back after the pumps stopped (20 min) and the water is just a hint cloudy and can't see anything falling out on the floor or skimmer bottom. Is this normal? I'm planning on draining in ~2 days, but I was assuming it would also be easy to just vacuum off the bottom (winter fix without draining). No complaints though if that's how it works as I was expecting some messing around to make sure the stuff got sucked up by the intakes over and over again.

That "olive" odor I described could also be thought of as canned hearts of palm, for sure. I didn't say earlier, but this happened twice. I had just done an Ahhsome purge and refill, followed by a math mistake that led to ~25 ppm bromine at startup. Five of us just all plunged in to reduce the bromine quickly and then used it a few days in a row. Bromine was still a bit high though at 10 ppm. The "odor" appeared a couple days later which led me to believe that I had some sort of disinfectant byproduct issue (maybe even some burned off plastic monomers from spa or cover even) and I drained/refilled a second time. Same odor came back a few days later again even with in-range bromine. I started analyzing it piecewise, and I realized there were some other subtle changes compared to last water batch: 1) water source, 2) brand of CaCl2. Water is from a different season and the creek where muni water is sourced is running low due to droughts. I switched to some no-name bulk bag of CaCl2 dried chips for swimming pools. Strange though that the odor wasn't there immediately upon fill and dosing startup chem. Maybe a [bacterial] impurity in the CaCl2, similar to the roof runoff gunk @Shanti observed? Odor did eventually go away after a couple weeks though. I'm due for another water change soon so I'll see what happens then.

I've been curious for years now about what I believe to be a once available option or planned add-on to the Sundance spa systems. I have a 99 Sundance optima, and the LCD display has available a "pH" and "ORP" indicator, presumably meaning that there could be pH and ORP probes added to the plumbing at a later date and hooked up for ultimate convenience. I've searched around but can't find any info on it. Interestingly, my spa has a new "sentry 850" motherboard installed in 2016 (but with original touchpanel/LCD), and it looks like the "pH/ORP" indicator is lit up by the same bit that indicates the optional filter change/clean interval has been reached, which is a new feature for this version of 850 board installed. Anyone have experience with Sundance onboard probes, if they ever existed? I dream of having an online ORP probe with automatic liquid chlorinator addition!

This is an old post, but this SpaGuard question is relevant still. I was given some SpaGuard Enhanced Shock (long story) and I wanted to figure out if I should use it. First glance I was thinking yeah I can use this as a source of dichlor, but the "other" ingredients accounted for ~50%. The label states that it is a shock, not for direct use of sanitizer. Found the SDS and there is in addition to dichor 10–30% sodium persulfate, ~10% aluminium sulfate (flocculant), ~10% "trade secret boron salt" (probably adjusted boric acid). Quite the cocktail and yeah it probably should not be used for daily sanitizer maintenance, but an all-around weekly maintenance item. Note that persulfate is NOT to be confused with the frequently mentioned "non-chlorine" monopersulfate/peroxymonosulfate/MPS. Sounds fine for shock assuming my CYA is within reason; however, I dose my borax at fill time and don't need any more. Is it bad to have high boric acid, assuming pH is kept adjusted? Also, I read posted elsewhere, I believe by @chem geek, that persulfate is an irritant (I assume more so than MPS). Also, it won't oxidize chlorides or bromides back to life. Any more thoughts or insight on the persulfate vs MPS usage here?

I just refilled my tub a week ago and I am having a strange odor that is appearing now that I've never experienced before. When I open the lid and turn on the jets, I sense a strange olive-like/corn-like offensive smell that slowly dissipates but is definitely coming from the water as the jets bubble it out. There's also almost an acidic tinge as well. Now, you may be thinking "put some sanitizer in there, quick!", but I have been maintaining total bromine between 1–6 since startup. My main concerns are that I am either dissolving plastic from the cover or tub somehow or that I'm creating nasty disinfection byproducts. The only change I've made is immediately starting up on a bromide bank with dichlor instead of using bromine tabs. Some details: 1999 Sundance optima. TA = 80, CH = 250, pH = 7.6, borates = 40 ppm B, +30 ppm NaBr. I have a JED ozonator running about 6–8 h/d depending on heater demand (there's some blistering on the cover where the circulator jet bubbles, but never any odor in the past besides the smell of "clean"). I purged it with ahhhsome prior to drain with a thorough rinse. I'm using dichlor dosed as needed and will switch to bleach soon. Any ideas?

I also am starting to suspect a biofilm issue in my tub with what seems to be excessive sanitizer consumption without bathing, but I want to clarify this comment. Does ozone also destroy FC in a short timespan? Same for bromine? I'm assuming this is resulting in inactive chlorites/chorates and bromites/bromates but I thought that would be a slower process.

Yeah, I think that's a good plan to start up with dichlor either way. I don't know what the burn up rate is of my bromine bank due to the ozonator, so if I ran low without knowing, it would be very good to have some chlorine buffering. I may also run a week or two with bromine tabs to build up DMH to a low level...I suppose though that bromine based SWGs don't mess with that, so maybe it's really not a concern.