Vacation Question

[ur_too_crazy]

I am presently running Nature2/Dichlor(powder) as the sanitation method in my spa. We will be leaving on vacation for 1 week and can't get anyone to add dichlor to keep up a decent chlorine level. I have some left over Trichlor tablets and a floater (from before my PoolSpaForums days). I know trichlor tabs are not the greatest for spas, (thank you Forum people)but I figured popping a couple a the floater for the week should prevent my water from getting ugly? I also figure I'd keep the temp setting down to 80. Anyone see any problem with this?

[chem geek]

The main problem with the Trichlor is that it will probably dissolve too quickly at hot temperatures. However, since you are lowering the temperature to 80 first, it should actually be OK if you can figure out how to dial down the feeder A LOT since you only need a small amount of Trichlor. Use the smallest possible tab and have the feeder on the lowest possible setting. Also, make sure your TA is higher for the Trichlor, probably at 120 ppm.

I figure you'll probably only need to add around 0.5 ppm FC per day at the most to maintain 2-4 ppm FC, assuming you don't have an ozonator. So over 1 week in 350 gallons this is only 0.18 ounces of Trichlor so far less than even a single 1/2" 1-ounce tablet. I don't know how you are going to be able to regulate it to deliver such a small amount over the week.

Let's figure a worst case where you use a single 1/2" 1-ounce tablet in 350 gallons and it fully dissolves. The good news is that it won't crash the pH if your TA is up higher (at least 100, but 120 would be better as this will prevent the pH from dropping below 7.0 if you start at 7.5). At the end of the week, the TA would drop around 14 ppm, the FC added would be around 20 ppm, and the CYA would increase by 12 ppm. So though not great, it's certainly not a disaster. The worst part is the high FC but with the CYA in the water it's equivalent to less than 1 ppm FC with no CYA -- maybe a lot less depending on the CYA level.

[ulty_dude]

I am presently running Nature2/Dichlor(powder) as the sanitation method in my spa. We will be leaving on vacation for 1 week and can't get anyone to add dichlor to keep up a decent chlorine level. I have some left over Trichlor tablets and a floater (from before my PoolSpaForums days). I know trichlor tabs are not the greatest for spas, (thank you Forum people)but I figured popping a couple a the floater for the week should prevent my water from getting ugly? I also figure I'd keep the temp setting down to 80. Anyone see any problem with this?

Hey, I have the exact same scenario ! Might be able to have a buddy come by one day but not sure. Any suggestions would be great. What temp should I set the spa at while away?

[PFC5]

You would think someone could come up with a tablet form for chlorine that can work well in spa temps so people can go away for a week. What does everyone with hot tubs do? Do they stop taking vacations? Heck this would also make spa care easier and likely make someone rich who created it.

What do you say Chem Geek? lol You seem to have the knowledge to create such a product.

[waterbear]

You would think someone could come up with a tablet form for chlorine that can work well in spa temps so people can go away for a week. What does everyone with hot tubs do? Do they stop taking vacations? Heck this would also make spa care easier and likely make someone rich who created it.

What do you say Chem Geek? lol You seem to have the knowledge to create such a product.

There is such a product, it's called bromine.

[PFC5]

You would think someone could come up with a tablet form for chlorine that can work well in spa temps so people can go away for a week. What does everyone with hot tubs do? Do they stop taking vacations? Heck this would also make spa care easier and likely make someone rich who created it.

What do you say Chem Geek? lol You seem to have the knowledge to create such a product.

There is such a product, it's called bromine.

I know but that is NOT chlorine. Does that mean when people go on vacation if they have a chlorine spa they have to change over to Bromine for the vacation? Then they would have to drain it to go back to a chlorine spa especially if they have a reaction to bromine.

You would think someone would/could come up with a relatively pH neutral tablet form of chlorine so that a floater could be used, both for everyday use, and also maybe for filling the floater up while away on vacation. We have enough trouble getting someone to just add a 1/2 cup of Dichlor to our pool while away on vacation, never mind all the work it would be to explain how to care for our spa while gone for a week.

[waterbear]

You would think someone would/could come up with a relatively pH neutral tablet form of chlorine so that a floater could be used, both for everyday use, and also maybe for filling the floater up while away on vacation. We have enough trouble getting someone to just add a 1/2 cup of Dichlor to our pool while away on vacation, never mind all the work it would be to explain how to care for our spa while gone for a week.

I was being a bit facetious when I said bromine but it does illustrate the main advantage of bromine over chlorine. The problem is not in the formation of a tab but in the actual chemicals themselves. BCDMH and DBDMH (the chemicals that make up bromine tabs) are slow dissolving in hot water such as found in spas.

The inorganic chlorine compounds are either fast dissolving or liquid (lithium hypochlorite, calcium hypochlorite, sodum hypochlorite)

The chlorinated isocyanurate are the other chlorine chemicals that we use. Dichlor is very fast dissolving, faster than the solid inorganic chlorines, in fact (lithium hypochlorie and calcium hypochlorite). Trichlor is fairly slow dissolving at normal pool temps but dissolves pretty fast at the higher temps in a spa AND it is very acidic. Because of the small volume of water in a spa it is too easy to deplete the TA and have the pH crash dangerously low, particularly if the spa is unattended while you are on vacation.

So there you have it in a nutshell. If you want the convenience of using a floater for automatic dispensiing of sanitizer you need to switch to bromine. If you want to stay with chlorine then you could look into a peristaltic pump to dispense liquid chloriine (sodium hypochlorite) BUT while such a system can automate the introduction of chlorine they do NOT make maintenance easier since the pumps and tubing do need a lot of attention, from my experience.

What I would suiggest is to turn the heat down, don't worry about the spa until you get back, and then deal with it. If the weather is cold you probably won't have any problems that a good shock won't take care of. If it is warmer you might have some nasties growing bu once again, by shocking (elevating the chlorine and keeping it there until the CC is 0 ppm and the FC is holding and not dropping--same as with a pool) you can get back to normal fairly quickly.

[PFC5]

I may try bromine again come spring/summer when it is easier to change the water if I have the same problem with cloudy water soon after filling. I have a strong feeling it was because it was a brand new spa and needed a flush as to why it couldn't hold a bromine reading even with 3 tablets and having the floater fully open and an abundance of bromide already in the water.

But what happens when someone comes from the chlorinated pool in the summer and goes in the spa and vice versa? Would that be a problem with the pool chlorinated why the spa is bromine? I suspect (it will be the first time both are open at the same time since I just got the spa this past November) there will be a lot of going back and forth between the pool & spa during the summer. I worry about that.

[waterbear]

I may try bromine again come spring/summer when it is easier to change the water if I have the same problem with cloudy water soon after filling. I have a strong feeling it was because it was a brand new spa and needed a flush as to why it couldn't hold a bromine reading even with 3 tablets and having the floater fully open and an abundance of bromide already in the water.

But what happens when someone comes from the chlorinated pool in the summer and goes in the spa and vice versa? Would that be a problem with the pool chlorinated why the spa is bromine? I suspect (it will be the first time both are open at the same time since I just got the spa this past November) there will be a lot of going back and forth between the pool & spa during the summer. I worry about that.

The small amount of bromine introduced into the pool that way will not be problematic. Your pool will stay a chlorine pool. Adding a bit of chloirne to the spa certainly is not a problem! Remember, I favor bleach as my first choice oxidizer for bromine! A chlorine pool is just a big tank of very dilute bleach.

[chem geek]

Also note that if someone is only gone for 1 week, then shocking their chlorine spa if they also lower the spa temperature can have the chlorine last for the week. Though the normal chlorine loss rate in a hot spa near the start of the water change interval is around 25% per day, at cooler temps (say, 80ºF) the loss is more like 10-15% per day. Let's be conservative and assume 15% and let's say you shock the spa to 10 ppm. Then, the FC per day will be roughly the following comparing a cooler spa to a hot one soon after a water change and a hot one near the end of the water change interval:

........ 15% Loss . 25% Loss . 50% Loss

Day 0: 10 ppm .... 10 ppm .... 10 ppm

Day 1: 8.5 ppm ... 7.5 ppm ... 5.0 ppm

Day 2: 7.2 ppm ... 5.6 ppm ... 2.5 ppm

Day 3: 6.1 ppm ... 4.2 ppm ... 1.3 ppm

Day 4: 5.2 ppm ... 3.2 ppm ... 0.6 ppm

Day 5: 4.4 ppm ... 2.4 ppm ... 0.3 ppm

Day 6: 3.8 ppm ... 1.8 ppm ... 0.2 ppm

Day 7: 3.2 ppm ... 1.3 ppm ... 0.1 ppm

Now in practice there may be some additional demand that is more fixed as the chlorine level gets low, but you can usually get by for 1 week assuming you shock high enough (and don't have a lot of leftover chlorine demand from an earlier soak) and have the water be cool enough. Two weeks, on the other hand, would be far more difficult.