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Major Chlorine Problems


chutch15
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My wife and I bought a Hot Spring hot tub back in August and have had consistent chlorine issues (or so we suspect) from the very beginning.

Here are our basic specs...

Hot Springs Pulse (400 gallons)

Ozonator

Silver Ion system

We use our tub about 3-4 times a week and are very careful about lotions and long hair getting in the tub. Foam and cloudiness haven't been much of an issue. Our big issue is that once we add chlorine (or oxidizer for that matter), it is all but gone by the next day.

Since we have an ozonator AND the silver ion system, what should our chloride level be? 3ppm is the acceptable level for a typical tub, but what about ours with these additional purification measures? We have been told that it can be lower. Is this true? If so, what ppm is our target?

Our dealer has not been very helpful with our water chemistry to date. We seem to get different answers each time we take water samples in to be tested. Their answers always seem to involve more chemicals, which feels wrong based on our tub's systems, but we don't know what else to do. This should not be this hard.

We have drained the tub once and have been cleaning our filter regularly.

Help!

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You are probably not adding enough chlorine to handle your bather waste, though with an ozonator and your higher usage you should normally not need to add as much. If you had no ozonator, then every person-hour of soaking in a hot (104ºF) tub would need roughly 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach (3-1/2 fluid ounces of 8.25% bleach) or 7 teaspoons of non-chlorine shock (43% MPS) to oxidize bather waste.

What you should do is increase your chlorine dosage after your soak such that you measure at least a small 1-2 ppm FC residual for the start of your next soak. Since you already have silver ions, you might consider using MPS which won't break down from ozone the way chlorine does, though MPS is more expensive than chlorine (especially more expensive than bleach). You might consider the Dichlor-then-bleach method but if you do then the TA should be lowered to around 50 ppm and the use of 50 ppm Borates is not optional.

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We already add more chlorine than I thought we would ever have to, especially considering that we have the ozonator and silver ion. We add a few capfuls per week.

What is the effect on chemistry of the ozonator? Silver ion? Our dealer doesn't seem to have an expert grasp?

Also, what is the correct level for hardness? Our strips tell us one range, but the bottle of Hardness Increaser and our dealer each have different ranges.

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You are correct that with an ozonator you shouldn't need to add as much chlorine when you use the spa regularly. On the other hand, in between soaks the ozone reacts with chlorine increasing your daily chlorine demand when you aren't using the spa to 50% or more of the FC level per day. With your usage, though, the ozone should be helping. So either it's not working as it should or you've got other things in the spa consuming chlorine. For a new spa, this is not unusual. The silver ion won't have any effect on chlorine usage. It would just let you use non-chlorine shock (MPS) instead of chlorine, at least most of the time.

The Calcium Hardness (CH) shouldn't be too high or else you can get scaling. A CH of 120-150 ppm will help prevent foaming.

Test strips are practically useless. The hardness is total hardness, probably not calcium hardness. The Taylor K-2006 test kit is the best chlorine test kit and you get what you pay for.

If you have never decontaminated your spa, then I suggest you use either SeaKlear Spa System Flush or Ahh-Some just before you change your water. That should remove biofilms from plumbing as well as any leftover grease from manufacturing.

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Also, the more sodium dichlor-chlorine you add, the less effective it becomes. With every 1ppm of chlorine, you're adding almost as much CYA (chlorine stabilizer)-which limits the effectiveness of the chlorine. Try adding MPS on a per use basis instead of the chlorine, and use the chlorine to "shock" once/week (If you read the instructions that came with your Nature2 silver ion cartridge, this is exactly what they recommend)

I'd measure the CYA levels as well. Drain and start over if it's too high- the chlorine is not effective if there's too much stabilizer (CYA) in the water.

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Hello, I'm hoping to find answers to FC chlorine issues that I am having also. I am new to for forum and new to hot tub water chem. We have a 400 gal. Strong spa that has an ozonator. The trouble I am having is that once done using the spa I will sanitize it, using Sodium dichlor-s-triazinetrione 2 teaspoons. the instructions on the back call for 1/2 teaspoon per 100gal. After I let the pumps run for 15 min. or more and I test it with a test strip FC readings are correct, however next day ill come back and check and it will be 0. Three of use the spa just about everyday at the sametime. to give you an idea of the other pramaters of my water I'll share the other levels I have checked using a Taylor K-1005 test kit. PH 7.5, TA100, CA 100, I did this test shortly after adding chlorine so at this point FC 3, CC 2. One thing I will ad is that we started using the tub got warm enough to add chemiclals and the readings on the test strips that came with or starter pack were within range( not sure if our impatients may play a part in the problem). Also The shock oxidizer states it is a weekly use on the front but on the back it says to use after every use. ( I have not been using it after every use). Should I be using the sanitizer and shock after every use. Also water is somewhat cloudy and gets foamy when all jets are on. Sorry for the long post and thanks in advance for everyones time and help.

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Is this a new spa? If so, your first fill won't last as long and you will want to clear out your spa by using either SeaKlear Spa System Flush or Ahh-Some just before you change your water. That should remove biofilms from plumbing as well as any leftover grease from manufacturing.

How long are the three people soaking in the spa? If for 30 minutes, then that would be 1.5 person-hours of soaking which would need 5-1/4 teaspoons of Dichlor to handle the bather waste if there were no ozonator. With an ozonator, you might need perhaps half that amount, so roughly 2-1/2 teaspoons of Dichlor. Your spa usage is heavier than what is assumed for the extremely overly simplistic "1/2 teaspoon per 100 gallon" rule.

You can use some non-chlorine shock to reduce the amount of Dichlor you need to add (the Dichlor-then-bleach method would be the least expensive, but it requires more setup of the water). You need to use at least some sanitizer after the soak because the non-chlorine shock is not a sanitizer.

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So here is what I have done, and it seems to be working. Nobody has been in the tub for a couple days. Two days ago I shocked and added some chlorine. When I got home this morning I tested chlorine 0 FC and 2 TC. so that would mean I have a CC of 2 right? According to the booklet that came with my test kit it says to reduce CC is breakpoint chlorination, and that would be my CCx10 which in my case is 20. The chart in the booklet doesn't have the exact % of available chlorine as the product I have so I went with the closest % that was less then what I have. That was 45%. The math was .03x4 (400gal)=.12 .12x20=2.4 oz. added that amount of chlorine cycled the pumps and tested. My kit is a color match and the color exceeded the color on the comparator, but actual ppm I do not know. Now several hours later the color matches 5 ppm FC and TC. Water looks much clearer then it has. Am I on the correct path? My plan is after tomorrow when I replenish chlorine, and shock oxidizer that I will use both after each soak. Thanks again for the help. I hope I'm getting this figured out. I have also ordered the Taylor k-1515-c in order to get more precise chlorine readings.

And to answer the question, yes it is a new spa, so I have ordered seaklear.

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You don't get rid of CC with the 10x rule as that rule is incorrect, but you do add chlorine to get rid of CC and you did that. When you get too low an FC, with or without CC, the day after your soak, that means you didn't add enough chlorine after your soak. Sounds like you are now on the right track.

However, keep in mind that non-chlorine shock will show up as CC in the FAS-DPD chlorine test that you have. If you want to continue to use non-chlorine shock, then this will be confusing. There are MPS test strips (one of the few test strips that are OK) or there is the Taylor K-2042 kit.

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