Spa Using A Ton Of Chlorine

[Emprov]

We bought a Hot Springs Caspian (about 350 gals), and are absolutely loving it so far. Hot Springs recommends Lithium Hypochlorite and, when they installed it, the lead installer said, once we brought the tub to proper chemical levels, to throw in a capfull (about a heaping tablespoon), after using it and throw in two or three capfulls to shock once a week or so. Tried that for about a week and I couldn't get the chlorine level to where it was supposed to be. Finally dumped in about a cup of chlorine and it fell into where it's supposed to be. Since then, I've been adding from 2/3 to 1 cup daily to maintain a proper chlorine level. We probably use the tub 5 to 6 times a week, keep it at 100 degrees and have a cover. Seems like I'm having to going through chlorine at way too fast of a pace. Does this seem right to y'all?

[tony]

We bought a Hot Springs Caspian (about 350 gals), and are absolutely loving it so far. Hot Springs recommends Lithium Hypochlorite and, when they installed it, the lead installer said, once we brought the tub to proper chemical levels, to throw in a capfull (about a heaping tablespoon), after using it and throw in two or three capfulls to shock once a week or so. Tried that for about a week and I couldn't get the chlorine level to where it was supposed to be. Finally dumped in about a cup of chlorine and it fell into where it's supposed to be. Since then, I've been adding from 2/3 to 1 cup daily to maintain a proper chlorine level. We probably use the tub 5 to 6 times a week, keep it at 100 degrees and have a cover. Seems like I'm having to going through chlorine at way too fast of a pace. Does this seem right to y'all?

Though lithium hypochlorite is a quick dissolving granular chlorine and ok to use in a spa, it is not the most used granular chlorine. The only place I've heard of dealers recommending lithium is in Canada where dichlor, the most widely used granular chlorine, was at one time hard to find. There are two problems with lithium...it has a relatively high pH of around 11 and the available chlorine is about 35 percent (forgive me if my numbers are a little off). Dichlor has a pH of about 7 and available chlorine of 56 - 62 percent. With lithium you have to add twice the product to get the same free chlorine level. To top it off, lithium is one of the most expensive chlorines on the market. I know Hot Springs, the manufacturer, also recommends dichlor.

As far as the sanitizing routine...rather than throw this much in at this time and that much in at that time...after soaking you should add enough chlorine that your free chlorine level reaches 3 plus ppm tested with either test strips or better yet a good test kit. Once per week you should shock with enough chlorine that your free chlorine level reaches ten times your combined chlorine level which is the difference between your total chlorine level and your free chlorine level. Most people just shock to ten ppm and figure they have raised their free chlorine level enough to do the job. As an alternative, you can shock with non chlorine shock.

[Emprov]

Thanks for the info Tony! Right now, I'm using some test strips that came with the tub. Seems like they're the equivalent of idiot lights on a car so it may be time to invest in a good test kit.

[tony]

Thanks for the info Tony! Right now, I'm using some test strips that came with the tub. Seems like they're the equivalent of idiot lights on a car so it may be time to invest in a good test kit.

The truly informed use a test kit.

[Emprov]

The truely informed use a test kit.

The truely informed spell "truly" correctly. *ducks and hides*

Sorry, I can be a grammar geek sometimes.

Question: is it best to turn on the jets when adding chemicals or is it ok to simply let the heater take care of dispersing the chemicals?

[RickJ]

I always run my jets when adding chemicals.

[tony]

The truely informed spell "truly" correctly. *ducks and hides*

Sorry, I can be a grammar geek sometimes.

Question: is it best to turn on the jets when adding chemicals or is it ok to simply let the heater take care of dispersing the chemicals?

OOPS! Thanks for the correction. I also turn my jets on when adding chemicals.

[sassygirl]

Hi, I think I am getting ready to buy a better test kit other then strips. What would you suggest?

[Brock]

is it best to test water standing still in tub (water, not you ) or turn on jets first. I seem to notice a different reading if I test water that has sat a bit after a filteration cycle compared to that after turning on jets for mixing or another filteration cycle.

[TinyBubbles]

LOL, it's a good thing you cleared that up Brock. I pictured you twirling around in the water with your test strip. Sassy, Taylor makes good test kits. I just don't think I'm ready to deal with the hassle of adding drops to water and even mixing two vials together to get a reading for cya. I'm buying 7 way strips today and I'll see how that goes.

[dilauro]

For the past week, my FCI level has been sitting at 0. I've been adding the chlorine sanitizer 1/2 to 1oz almost every other day to bring up this value. Last Friday, I added the weekly shock treatment and at my next reading the FCI went up to 3, which I've been told is the recommended value.

What generally will cause the FCI value to be low? Should I be added more chlorine?

I am using Spa Care Solutions chemicals

[chem geek]

Ron,

Assuming that the chlorine sanitizer is Dichlor powder, and assuming your spa is 350 gallons, then 1/2 to 1 ounce will raise the FC by 6 to 11 ppm. Typical FC usage can be around 4 ppm per day if the spa is used nearly every day so it does sound like you are on the edge in terms of keeping up with chlorine demand. So yes, it does sound like you aren't quite using enough chlorine. You might find that if you use a non-chlorine shock that your chlorine usage won't be quite so high (you didn't say what kind of weekly shock treatment you used).

You could also switch to using bleach instead of the Dichlor powder since using the Dichlor powder will continue to raise the Cyanuric Acid (CYA) level in your spa making the chlorine less and less effective over time. You do want some CYA so you want to start off using Dichlor powder after a fresh refill for about a week or two, but then switch to unscented bleach. 3 fluid ounces of 6% bleach (Clorox Regular or off-brand Ultra) will raise the FC level by 4 ppm in a 350 gallon spa. Be sure to add the bleach slowly over a return flow with the pump running (or the jets running) so that it gets thoroughly mixed (you could also take a bucket of spa water, add the chlorine to the bucket, then add that bucket of water back to the spa, but that's not really necessary unless your spa isn't circulating).

Richard

[Emprov]

Assuming that the chlorine sanitizer is Dichlor powder, and assuming your spa is 350 gallons, then 1/2 to 1 ounce will raise the FC by 6 to 11 ppm. Typical FC usage can be around 4 ppm per day if the spa is used nearly every day so it does sound like you are on the edge in terms of keeping up with chlorine demand. So yes, it does sound like you aren't quite using enough chlorine. You might find that if you use a non-chlorine shock that your chlorine usage won't be quite so high (you didn't say what kind of weekly shock treatment you used).

So ideally I should be using a tablespoon or two a day if I'm using the tub, say, 5 times a week? Good info, thanks.

Shocked the tub last night using a Dichlor product that my local shop recommended. My FC and PH are now way off the charts. One day I'll get it all figured out.

BTW, have I said that you guys rock big time?

[chem geek]

Yup. One to two tablespoons is 1/2 to 1 ounce. Probably one tablespoon per day should be fine if it's added every day. You said you were adding every other day which is probably why it wasn't quite enough. Just adjust the dosage and see how things go. Again, I suggest you consider using unscented bleach for the daily chlorination and also consider using non-chlorine MPS shock instead of using Dichlor for chlorination and shocking. If you hate the thought of using bleach, then consider Lithium Hypochlorite powder or even Cal-Hypo as these will not increase the CYA level (though the Cal-Hypo will increase Calcium Hardness).

[Emprov]

Yup. One to two tablespoons is 1/2 to 1 ounce. Probably one tablespoon per day should be fine if it's added every day. You said you were adding every other day which is probably why it wasn't quite enough. Just adjust the dosage and see how things go. Again, I suggest you consider using unscented bleach for the daily chlorination and also consider using non-chlorine MPS shock instead of using Dichlor for chlorination and shocking. If you hate the thought of using bleach, then consider Lithium Hypochlorite powder or even Cal-Hypo as these will not increase the CYA level (though the Cal-Hypo will increase Calcium Hardness).

Ron was using a tbsp every other day. I was using a cup a day and it was still under 3ppm 18 hours later. Kinda bummed now though, my PH is way, way out of whack. Since shocking (Dichlor), two nights ago, I've probably put in a cup or more of PH Decreaser and it's still through the roof. Is it time to drain the tub?

[tony]

Ron was using a tbsp every other day. I was using a cup a day and it was still under 3ppm 18 hours later. Kinda bummed now though, my PH is way, way out of whack. Since shocking (Dichlor), two nights ago, I've probably put in a cup or more of PH Decreaser and it's still through the roof. Is it time to drain the tub?

No need to drain unless you feel it would be easier to start from scratch. Keep adding pH decreaser until it comes down.

[TinyBubbles]

I follow vermonter's method of adding chlorine to reach the right residual, not just adding say 1 tbs. because that sounds like the right amount. My spa is also 350 gallons and 1 teaspoon (actually a hair under) gives me a reading of 3ppm fc in 20 minutes, with a slight residual the next day. IMHO, 18 hours later you don't need a residual of 3 ppm.

[Emprov]

Woohoo! Ph is finally starting to show signs of coming down! Chlorine is still way, way high though. We'd love to be able to use the tub but, as high as the readings are, no way that I'm getting in. Is there any way short of draining some water out to bring the chlorine level down? Would cranking the heat make a significant difference? Guess I could let my kids go in for about an hour, that should do it.

[chem geek]

Running the jets with the cover off will help to outgas some of the chlorine, but mostly it gets reduced oxidizing organics so if those are mostly gone, then it will take longer to drop. I'd just keep the cover off and run the jets a bit -- however, note that this will also outgas carbon dioxide which will cause the pH to rise.

How high is "high" anyway? If you've got a high CYA level then the higher FC level may not be as bad as you think.

Richard

[Emprov]

Running the jets with the cover off will help to outgas some of the chlorine, but mostly it gets reduced oxidizing organics so if those are mostly gone, then it will take longer to drop. I'd just keep the cover off and run the jets a bit -- however, note that this will also outgas carbon dioxide which will cause the pH to rise.

How high is "high" anyway? If you've got a high CYA level then the higher FC level may not be as bad as you think.

Richard

I'm using strips at this point so I can only test for pH, FC and alkalinity. pH seems to be well above 8.4, FC turns the pad a really deep purple, much deeper than the 10 ppm's purple. Alkaline is around 40 ppm, a tad low. There's also a ppm Stablaizer, which the lead spa installer told me to ignore but it's in the 30-50 ppm range. If pH and FC aren't significantly better tomorrow, think I'll drain about a third of the water out. It's only been 2 days since we haven't been able to go in (counting tonight), but it seems like a lot longer.

[Emprov]

Update: Finally got tired of trying to balance everything (FC never did come down since I shocked), and just decided to drain and refill. Did that and the Ph an Alkaline came into line really easily. I decided to give Dichlor a try so I added a touch over a tablespoon and, when I checked, the FC was between 5 and 10 ppm. Man, it was taking almost a cup of lithium to get those results! I'm guessing that there was some other funky stuff happening with the spa but it seems all good now!

[TinyBubbles]

Congrats, hope things go better for you on this fill. FYI, there are strips out there that will test for combined chlorine.

[Emprov]

Congrats, hope things go better for you on this fill. FYI, there are strips out there that will test for combined chlorine.

So far so good, thanks. 2 questions: what is the real world difference between FC and combined chlorine? And, how much of the time do I want the water to be at 3ppm? If I get it there or slightly above after using it at night, by the next day it's slipped down well below that level. Whatever the case, I'm using about a tablespoon a day, which is much, much better than the cup a day that I was using before.