Not having success with BBB in my hot tub

[chem geek]

In regards to what I was adding with the Baquacil, I'd have to say....I don't know! I just bought the stuff they said to in the book and stuck it in when the test strips recommended it. They were called: A. Sanitizer. B. Shock (recently they changed the name to oxidizer.) C. Waterline control. Also obviously PH & alk up and down, and their "water clarifier" that didn't work worth a darn....

Now for a question on Pseudomonas aeruginosa...Knowing that one has it in one's tub, how high would the CL need to be and for how long would it need to be there to kill it off?

The "A. Sanitizer" was probably Biguinide (PHMB) while the "B. Shock or Oxidizer" was probably Hydrogen Peroxide. So the shock should have oxidized organics and you should not have had cloudy water, but then again who knows what happened...

As for Pseudomonas aeruginosa, it looks like the CT (chlorine concentration times time in minutes) values for this bug are on the order of 50-70 which would mean it would take about 20 minutes to kill 99.99% of the bugs at a 3.0 disinfecting chlorine level, but I do know that the commercial spas study measured pseudomonas and found that the 650 mV ORP level which roughly corresponds to the 0.011 ppm disinfecting chlorine level was sufficient to prevent these organisms from growing. However, once they are started, they can form biofilms and require much more chlorine to kill which is what the 50-70 CT value represents. Bottom line is that Ben's best guess chart is probably sufficient for preventing it (his minimums are around 0.02-0.03 disinfecting chlorine), but you need to shock regularly to get rid of it once it's there. Since it is so hard to control sanitation levels in the small volume of water, setting an initial target of around 5 ppm chlorine would be good and try never to drop below 3 ppm. You mostly need that amount of chlorine simply to oxidize the organics, that is, to never run out. If you use any CYA at all it should be a very small amount (< 10 ppm) so that you can easily shock to get to high chlorine levels when needed.

And I agree with previous posters that bromine can be easier to use in this sort of situation, but I also understand your desire to get that wonderful BBB feel. My hunch is that if you shock your spa and keep it at shock levels until the chlorine doesn't drop anymore, then you'll have a clean-water starting point. Then any chlorine usage would be related to your usage of the water and you'll just have to drop in an amount of chlorine after each use. Some websites even recommend a shock level after each use, but that's probably for heavier usage (i.e. 6 people in a 4-5 seater).

Richard

[keithw]

Richard,

Well just got home and checked my levels and you are correct on the CYA. Tested with Taylor K-2006 so should be pretty accurate.

FC 10.6
CC 1.2
CYA 100
ALK 130
PH 7.5

Since the CYA is so out of whack, I guess I will just drain and start over and give it one last shot.

My hunch is that if you shock your spa and keep it at shock levels until the chlorine doesn't drop anymore, then you'll have a clean-water starting point.

My problem has been that I could never reach a point where the CL wouldn't drop any more. Gonna give it one more shot though.

[chem geek]

Gonna give it one more shot though.

When you do the drain and refill, there will still be residual CYA in the pipes and stuck to the walls that you can't get rid of so just be aware that there will still be a small amount (probably < 5 ppm, perhaps only 1 ppm though you can try testing for it to see). I suggest you not add salt to see if that makes any difference. Notice that you have a large FC now, but also have CC which makes me think that indeed there is something consuming a lot of chlorine in your tub.

I'm keeping my fingers crossed that the chlorine will hold this time, at least after some initial use. Keep us posted.

Richard

[RavenNS]

Unfortunately I don't really have a moment right now to go into all this...
lets just say,
(1) forget the bleach... too much trouble for what it's worth & it will most likely end up costing the same or more than bromine anyway ( due to dissapation factors)
go with Bromine
(2) I agree with Chemgeek... forget the salt... you don't need it.
- you'll get the same "soft" feel from spa products usually called "soft" ( with way less tds & chemical solvents)... it usually only takes one small squirt every once in a while
(3) don't add CYA
(4) use puck floaters ( they will most likely have a bit of stabalizer anyway)
- make sure that the floater is Never empty... this will ensure that your level doesn't drop to zero... around 6ppm sanitizer is a good number to shoot for.
(you can still use sodium carbonate or bi-carbonate products & you will still need to add calcium...)

I would suggest checking your hot tub manual for recommendations of levels...
then check your old baqu system to see what "job" each chemical was doing ( some of your "start-up" chemicals may not be replaced with grocery items, but we may be able to suggest other chemicals instead of Baqu-crap system);
then you can then figure out what chemicals can be replaced by grocery store items ( or BBB... Bromine, Baking soda, Borax)...

as long as your sanitizer ( bromine or chlorine) is high enough to do it's job ( not interupted by CYA) then the "itch" or bacteria causing it, should Not re-occur....

if you have a product called " tub clean" or something similar to it, run it through before draining the tub... be sure to either replace your filter or use a filter cleaning chemical ( like filter pure, or filter cure) soaking it over-night
or about 24 hours would be ideal

Best of Luck

[keithw]

Yep I am going to nix the BBB on the tub. Tested tonight and the CL was 0. I was at 10.6 yesterday at the same time. The tub hasn't been used in three days so it cannot be anything that we are putting in that's killing the CL. It just disappears so fast in such a small tub, I guess. Don't see any choice but to drain tomorrow and re-baquacize it.

[keithw]

Just an update. Decided to give CL one last shot. As Richard and I discussed, my CYA was high so I did a drain and refill and have the CYA at 30PPM now. Also gave up on the salt since Richard suggest that it oxidize the CL faster. Things appear to be much more stable after the refill. I can hold a CL greater than 6PPM for a day day or two now so maintaining the tub with CL is now tolerable.

[chem geek]

Just an update. Decided to give CL one last shot. As Richard and I discussed, my CYA was high so I did a drain and refill and have the CYA at 30PPM now. Also gave up on the salt since Richard suggest that it oxidize the CL faster. Things appear to be much more stable after the refill. I can hold a CL greater than 6PPM for a day day or two now so maintaining the tub with CL is now tolerable.

Thanks for the update. The lower CYA level will keep the sanitation level of chlorine up while the elimination of extra salt (chloride ion) will cut down the outgassing of chlorine gas (it's not that it oxidizes faster, but that it gets converted back to chlorine gas -- the opposite of dissolving chlorine gas in the water).

As others have mentioned, using Bromine is quite typical in a spa so if you get frustrated with the chlorine just switch. Keep us posted, especially if anything changes (e.g. you experience hot tub itch, or you start to lose too much chlorine, etc.).

Richard