Vacation

[rckymtntim]

Here's another question for you guys. I'm going to be going on vacation and gone for about 6 days. My CD is approx. 35%. Can I bring my FC up to 40ppm before I leave? Will this have any negative on the spa? My calculations have my returning to a FC level of between 3 and 4ppm. I'm also using N2 and ozonator.

Thanks for all the help I've received here.

Tim

[quantumchromodynamics]

What is your cyanuric acid level?

[gman]

I have a 530 gal hot tub. I too have an ozonator and use N2. I have no problem maintaining some FC in my tub for 6 days by raising the FC to about 12 ppm. Although, I am not trying to keep the FC at 3 - 4ppm. My focus is just to be sure that I have sufficient FC in the tub to keep it sanitized.

Assuming that you do not take a soak just before you leave for six days, and that you added chlorine to your tub after your LAST soak AND you allowed sufficient time for the chlorine from your last soak to neutralize contaminants, I think you would only need to raise your FC level to about 12 ppm to maintain some FC chlorine level in your tub.

I'm not intending to "volunteer" anyone's assistance in particular, but I'm Richard or chemgeek, could provide you with the exact calculations if you provide them with sufficient water stats.

gman

[oldparr]

I'm leaving for a 15 day vacation. I use the dichlor/bleach method and I don't want to switch to bromine. My plan is to low the water temp to 60F (the lowest my tub can go), put 20ppm using bleach and leave a floating with 4 or 5 tablets of thichlor. I intent to raise the TA from 50 to 80 - to control the acid that will come from the trichlor.

I think that with 60F the CD will drop (now it is 30%) and the tablets will dissolve very slowly. I live in Dallas, so I'm not very concerned about freeze.

My CYA is 35 and CA is 150

What do you think about that strategy?

Claudio

[rckymtntim]

Quantum, My cya is approx. 35.

gman, my Chlorine Demand is approx. 35%. If I start with 40 ppm of FC I figure if I leave for 6 days it will be around 4 ppm. Is this correct? 40x0.65=26, 26x0.65=16.9... Am I correct in thinking this is how CD works?

[chem geek]

Quantum, My cya is approx. 35.

gman, my Chlorine Demand is approx. 35%. If I start with 40 ppm of FC I figure if I leave for 6 days it will be around 4 ppm. Is this correct? 40x0.65=26, 26x0.65=16.9... Am I correct in thinking this is how CD works?

Yes that is how it works -- 40*(0.65)^6 = 3

However, I wouldn't raise the chlorine that high. I think that without bather load you don't have to end up with a chlorine level of 3 ppm. If you raised the chlorine level to 20 ppm I think that would be fine. You would end up with around 1.5 ppm FC. If your higher CD is due to an ozonator, then it may keep the tub clean for a few days even if the chlorine level dropped (since, again, there won't be any bather load so no new introductions of lots of bacteria).

[chem geek]

I'm leaving for a 15 day vacation. I use the dichlor/bleach method and I don't want to switch to bromine. My plan is to low the water temp to 60F (the lowest my tub can go), put 20ppm using bleach and leave a floating with 4 or 5 tablets of thichlor. I intent to raise the TA from 50 to 80 - to control the acid that will come from the trichlor.

I think that with 60F the CD will drop (now it is 30%) and the tablets will dissolve very slowly. I live in Dallas, so I'm not very concerned about freeze.

My CYA is 35 and CA is 150

What do you think about that strategy?

Claudio

I'd be concerned about the Trichlor tablets. They are very acidic so you are right to raise the TA to help counter-act that, but with the cover closed on the spa there won't be much outgassing of carbon dioxide counter-act that acidity. You are right that the tablets will dissolve slowly at 60F -- that's a lot lower than even pool temperatures -- but are you using small Trichlor tabs used for spas? I assume you aren't talking about the large ones used for pools. Can you tell me the size of the tablets? Are they 1-ounce 1/2" tablets? If so, then one of these in 350 gallons would raise the FC by 20 ppm and lower the pH from 7.5 to 7.2. I think that 4-5 tablets is way overkill and dangerous, if these are the kind I just described. At the most I'd only use 2 tablets and have the feeder on its lowest setting -- if they both dissolved then that would be 40 ppm FC and a pH down to 7.0. Not great, but not a disaster either -- I still think one tablet would be safer.

Do you have an ozonator? If not, then the 30% CD sounds like you might need to clean your filter.

[oldparr]

I'd be concerned about the Trichlor tablets. They are very acidic so you are right to raise the TA to help counter-act that, but with the cover closed on the spa there won't be much outgassing of carbon dioxide counter-act that acidity. You are right that the tablets will dissolve slowly at 60F -- that's a lot lower than even pool temperatures -- but are you using small Trichlor tabs used for spas? I assume you aren't talking about the large ones used for pools. Can you tell me the size of the tablets? Are they 1-ounce 1/2" tablets? If so, then one of these in 350 gallons would raise the FC by 20 ppm and lower the pH from 7.5 to 7.2. I think that 4-5 tablets is way overkill and dangerous, if these are the kind I just described. At the most I'd only use 2 tablets and have the feeder on its lowest setting -- if they both dissolved then that would be 40 ppm FC and a pH down to 7.0. Not great, but not a disaster either -- I still think one tablet would be safer.

Do you have an ozonator? If not, then the 30% CD sounds like you might need to clean your filter.

Chem Geek,

I didn't buy the tablets yet. I was thinking in buying the 1'' ones and use them with the feeder in the lowest setting. Do you think they are too large? I have a 650 Gal tub. I tested my CD a while ago. I'm going to clean the filter and test it again. Should I expect a significant drop in the CD with lower temps (lower than 100Fº)?

Thanks

[chem geek]

I would expect a significant drop in CD at lower temps. I can tell you that in my pool at 88F, the chlorine demand with the opaque pool cover on and not in use is around 0.7 ppm FC per day while at 50F it is 1 ppm FC every 2 weeks. The temperature makes a substantial difference in chlorine usage (assuming no ozonator -- with an ozonator chlorine will still get used up fairly fast).

Others with experience with the pucks will have to chime in, but I'm concerned about it. If you don't use too many, then any excessive dissolving will have a limited effect, but as I wrote before, don't use too many pucks. One 1" one is already pushing it.

[oldparr]

Wow! After cleaning the filter and bringing down the temp to 57Fº, my CD went to 8%. I think that I'm going to put 20ppm and leave it without a floating.

[NewB@Spa]

I would expect a significant drop in CD at lower temps. I can tell you that in my pool at 88F, the chlorine demand with the opaque pool cover on and not in use is around 0.7 ppm FC per day while at 50F it is 1 ppm FC every 2 weeks. The temperature makes a substantial difference in chlorine usage (assuming no ozonator -- with an ozonator chlorine will still get used up fairly fast).

Others with experience with the pucks will have to chime in, but I'm concerned about it. If you don't use too many, then any excessive dissolving will have a limited effect, but as I wrote before, don't use too many pucks. One 1" one is already pushing it.

rckymtntim sorry to "hijack" your post...got a question for the experts. I am going to retest my CD maybe tomorrow, but almost two weeks after a fresh fill and balancing (using Nitro method) my CD is increasing dramitically. I have already switched to bleach. When last tested my #s were;

TA - 50

CYA - 30

pH - 7.6

Borates - 50 (estimated)

My issue is before a soak (1 person 1/2 hour) my FC is about 4 and I dose with ~1.5 oz of 6% bleach when I get out. Yesterday I dosed (did not soak ) and my FC this morning (< 24 hours) is about 1. Telling me my CD is >70% I can think of two cause...need to clean filter, which is tuff right now (~15 degrees!) and I have an ozonator. My tub is 425 gal @ 103 degrees. Can't use my garden hose to wash out. Is pressure hose at car wash too strong?

[rckymtntim]

No problem NewB.

Here's a couple more things.

I left for a work stint Monday Feb. 1st. Before leaving that morning I added 1 1/2 cups of bleach to my 165 gallon spa. I checked the FC about 30 minutes later and found my FC to be about 30 ppm. On Wed. Feb. 3rd my wife added a 1/2 cup of bleach. She did not add any bleach after Wed. Due to a snowstorm I was able to get home on Sunday Feb.7th. When I returned my FC was 2.0. I didn't add anything and checked today and had a FC of 1.2 giving me a CD of 40%.

I'm leaving this Wed. for vacation, If I add 2 cups of bleach before I leave that morning will this be enough to carry my FC through the week I will be gone?

[chem geek]

A chlorine demand (CD) of 40% would mean that after a week only 0.6^7 = 2.8% of the chlorine will be left, or perhaps 1.2 ppm FC. This is dicey, however, since the CD percentage works well for chlorine loss due to thing like outgassing, oxidizing organics in the tub, etc., but may not be as accurate when one has an ozonator, though that's what we've been assuming so far. So this seems dicey in your case for two reasons -- we're not sure it will really last and raising the FC to around 45 ppm which is what you would be doing is pretty high a chlorine level, even with CYA in the water.

If you are going on vacation, can't you lower the water temperature significantly? That should cut down chlorine demand from most losses significantly. I don't know how much it will cut down the loss from an ozonator -- all chemical reactions slow down at lower temps but I don't know how much slower it would be for the ozone oxidation of chlorine.

If you did a test similar to what oldparr did, then you'd know more about how your tub will respond at lower temps on vacation. Sorry I can't help you and predict, but I'd rather not guess about this. My guess is that if you lower the temperature, you won't need to go above 20 ppm FC to last.

[rckymtntim]

Thanks chemgeek, I will turn down the heat on the spa when I leave and see what happens.

Here's a little more info. This morning I checked my FC it was 1.2ppm. I added a 1/2 cup of bleach and now after leaving the jets running for 20 minutes on full it then went through a cleaning cycle. My FC is now at 8ppm Do these numbers make sense? How long does it take for the bleach to mix in the spa?

[quantumchromodynamics]

You might want to turn the ozonator off while you are away.

[rckymtntim]

thanks quantum, I'll do that also.

[chem geek]

1/2 cup of 6% bleach would theoretically raise the FC in your 165 gallon spa by 11.7 ppm. The chlorine from the bleach will mix quickly, especially if the pump is running, but having the jets on probably had some of the chlorine outgas and some other of the chlorine may have reacted with some things in the water. It may also be that your bleach is weaker than it should be or your spa size is larger than you think. Are you using Clorox Regular that says "6% Sodium hypochlorite" in the ingredients and also says "5.7% Available Chlorine"?

[kbaumann]

I am going to pick up some Leslies Blue Calcium Hypochlorite Tablets tomorrow… I want to experiment with taking a tab and putting it in a floater… I want to see how fast it dissolves in a spa at 102F-104F… I will use a floater where the bottom is sealed and then drill two 1/16” holes above where the tab will lay so there will not be anything to drop out as it dissolves… I know this will add calcium to the spa, but it will not add CYA… We have more room to play with calcium on the CSI… I also thought of wrapping the tab in .5 microm filter mesh to see if it will control the speed it releases/dissolves… This will be in a spa that is not used for the week and has a clean filter…

Any ideas at all?

[quantumchromodynamics]

I think that those tabs are 3 inch diameter and would be too big for spa use.

Also, wrapping tabs in any type of a filter mesh is a bad idea because the chlorine will destroy most fabrics.

http://www.lesliesmsds.com/DocumentCenter....bb-e126ab9e28e5

[Mikey_in_NY]

Just for everyones information I've been using the Dichlor then beach method for around 6 months now (first and only water change was mid December). Anyway, I've just returned from 10 days vacation and was worried what might happen to my water balance during this period, so I was very relieved to find the water was crystal clear with no smell, although FC and CC were down to 0.0 and 0.5 respectively, TA was 60, PH 7.4. Needless to say I've now added some chlorox to get the chlorine numbers back to where they need to be.

The day I left for vacation I added 16oz chlorox and 3 TBSP of MPS, and turned temp down to 90F. Tub is 540 gallon with 24 hour circ pump and CD discharge ozonator, and Sunpurity (Nature 2) cartridge. I run two 30 minute filter cycles per day.

I'm not saying this will work for everyone, but it sure worked for me for a full 10 days.

[SJ Hart]

Just for everyones information I've been using the Dichlor then beach method for around 6 months now (first and only water change was mid December). Anyway, I've just returned from 10 days vacation and was worried what might happen to my water balance during this period, so I was very relieved to find the water was crystal clear with no smell, although FC and CC were down to 0.0 and 0.5 respectively, TA was 60, PH 7.4. Needless to say I've now added some chlorox to get the chlorine numbers back to where they need to be.

The day I left for vacation I added 16oz chlorox and 3 TBSP of MPS, and turned temp down to 90F. Tub is 540 gallon with 24 hour circ pump and CD discharge ozonator, and Sunpurity (Nature 2) cartridge. I run two 30 minute filter cycles per day.

I'm not saying this will work for everyone, but it sure worked for me for a full 10 days.

What is the difference between your 24 hour circulation pump and filter cycles? Does't the filter run whenever the circulation pump is on?

[Mikey_in_NY]

Just for everyones information I've been using the Dichlor then beach method for around 6 months now (first and only water change was mid December). Anyway, I've just returned from 10 days vacation and was worried what might happen to my water balance during this period, so I was very relieved to find the water was crystal clear with no smell, although FC and CC were down to 0.0 and 0.5 respectively, TA was 60, PH 7.4. Needless to say I've now added some chlorox to get the chlorine numbers back to where they need to be.

The day I left for vacation I added 16oz chlorox and 3 TBSP of MPS, and turned temp down to 90F. Tub is 540 gallon with 24 hour circ pump and CD discharge ozonator, and Sunpurity (Nature 2) cartridge. I run two 30 minute filter cycles per day.

I'm not saying this will work for everyone, but it sure worked for me for a full 10 days.

What is the difference between your 24 hour circulation pump and filter cycles? Does't the filter run whenever the circulation pump is on?

You're right to ask that question, guess I should have chosen my words better!

Yes, the circ pump does filter continuously in conjunction with the ozonator and heater.

When I said 'filter cycles' I was referring to running the 2 main 2.5HP jet pumps for programmable periods. These pumps operate completely independant from the circ pump. The choices are:

5 mins every 12 hours (basically just to flush out the lines)

30 mins every 8 hours (what I'm currently using)

30 mins every 6 hours

30 mins every 4 hours