Making The Switch To Dichlor

[RFD100]

For the past year I have used Bromine and I ready to switch to Dichlor/Bleach method as I’m tired of the bromine smell both while in the tub and on your body after each use. However I have a few questions after reviewing Nitro’s write up. Each fill up I use Leisure Time PH Balance to hold the PH level. Can I still use this, or do not need it anymore?

Is there a better brand of Dichlor to buy? I was looking a Spa Choice from the Spa Depot.

Thanks

[chem geek]

Most spa pH balance products for lowering the pH are sodium bisulfate and that's OK to use though if you lower the TA sufficiently you shouldn't be needing to use very much of it.

As for Dichlor, just get product that is relatively pure so 95+% "sodium dichloroisocyanurate" or "sodium dichloro-s-triazinetrione" or "sodium troclosene" (usually with "dihydrate" after that name) which are all synonyms for the same thing. It could also say 55+% available chlorine.

[quantumchromodynamics]

Leisure Time pH balance Plus is boric acid.

MSDS

Leisure Time pH balance is a combination of Dipotassium phosphate and Monosodium phosphate.

MSDS

MSDS/All

Boric acid is fine to use. The phosphate is fine to use if you have lower levels of calcium. Since you have used it previously, then you should not have any trouble. I would recommend the boric acid to add 50 ppm borates. I don't recommend the phosphate, but I don't think it would hurt as long as you don't need calcium and your tub is not exposed to sunlight.

[RFD100]

Our tub sets under a covered deck so sun light is not a problem. The City water has a CH of 150 to 160. Is that a good level?

Thanks

[quantumchromodynamics]

Are you using the pH balance or the pH balance plus?

The pH balance is the phosphate buffer. Large amounts of phosphate will combine with calcium and precipitate out. When you used it previously, was there any cloudiness or precipitation when you added it?

I really don't think that phosphate buffers are worthwhile. I would skip the phosphate and just use borates.

[footie]

I took it that all chlorine based tablets continued to add CYA into you water, I thought that once you reached a limit of 20-30ppm of CYA you should switch to unstable chlorines.

Is that not right?

[quantumchromodynamics]

I took it that all chlorine based tablets continued to add CYA into you water, I thought that once you reached a limit of 20-30ppm of CYA you should switch to unstable chlorines.

Is that not right?

Trichlor tabs do add cyanuric acid, and they should usually not be used in a hot tub. I'm not sure how your question is related to this post. There has not been any discussion about anyone using chlorine tabs.

The chlorine mentioned is dichlor, which adds cyanuric acid, and yes, you do stop using it once your cyanuric acid hits 20 ppm.

If you were intending to ask an unrelated question, please click on the "Start a new topic" button to start your own thread to help keep things from getting confusing.

[RFD100]

I have used PH Balance. The water well fizz when the pumps are on and is only cloudy after each used for about 5 to 10 minutes and would clear up. Also I assume just draining the tub and changing the filters is good enough, or do I need to flush and drain several times to get out all of the old bromine out?

[quantumchromodynamics]

I would skip the phosphates and just use the borates. You should drain the tub, refill, run, drain again and then refill again to get all of the bromine/bromide out.

[RFD100]

Thanks for the input. If I’m reading right I need 50ppm borates and I should use 20 Mule Borax. What exactly does the borates do?

[quantumchromodynamics]

You can use Borax and muriatic acid to add borates, or you can use boric acid.

I think that the boric acid method is better because it is mostly pH neutral. You can get boric acid from the chemistry store online for a good price. You should get enough to do several water changes.

The poolcalculator has the correct calculation for adding 50 ppm borates from Borax or Boric acid.

Borates help keep your pH more stable, especially if you have a salt water chlorine generator. Borates make the water feel better, and reduce skin and eye irritation. For outdoor pools and hot tubs, borates help prevent algae.

[RFD100]

Thanks for the input. I'll probably go with the borax and muriatic acid on this fill (because I have them on hand)and order some for future use. I assume you only have to do this when you fill the tub not part of on going weekly maintenance? I never mess with it when I was using bromine so I don't know much about it.

[RFD100]

Ok I have drained and flush out the tub and filled with fresh water. From the tap the PH is 7.5 and the TA is 160. I have adjusted the TA to 80 (added 8 oz of muriatic acid) and adjusted PH back to 7.5 through aeration. According to the pool calculator I need to add 24oz by weight of borax and 11oz of muriatic acid to adjust the PH back into range to 50 ppm of borates (400 gallon tub).

Do I add the 1.6 oz of dichlor now to get the cya to 30 ppm and then the 8.3 oz of bleach to get the FC to 10 ppm or just the dichlor only at this point?

[quantumchromodynamics]

It will take a total of 2.1 ounces (weight) of dichlor to get the cyanuric acid to 20 ppm. You don't add it all at once. You add it a little at a time as needed to maintain your chlorine. Once you have used a cumulative total of 2.1 ounces, you switch over to bleach.

When adding the Borax, I suggest that you add 1/2 of the acid, then 1/2 of the Borax dissolved in water, then the second 1/2 of the acid and then the second half of the Borax dissolved in water.

[RFD100]

I added half of the dichlor at 6 a.m. and was going to put in the other half about 6 to 7 p.m. tonight. When add some bleach tomorrow or is that rushing it?

[quantumchromodynamics]

I added half of the dichlor at 6 a.m. and was going to put in the other half about 6 to 7 p.m. tonight. When add some bleach tomorrow or is that rushing it?

You are adding the dichlor too fast. You should only add enough to maintain your chlorine. With no cyanuric acid, you don't need more than 4 ppm unless you have combined chlorine. You should add enough so that the chlorine is still at least 2 to 3 ppm by the next time you test. Once you achieve 20 ppm of cyanuric acid, you can maintain a slightly higher FC level. If you are getting combined chlorine or the chlorine is all gone by the next time you test, then you need to maintain a higher level. What test kit do you have?

[RFD100]

I have two test kits one is a Taylor Kit K-1004 and the other is a HTH 6 way test kit. Only the HTH test for cyanuric acid. I hope I have not messed this up by putting in half of the dichlor. Should I wait 24 hours before adding more?

[quantumchromodynamics]

You need the Taylor K-2006 FAS-DPD test kit to accurately measure your FC and CC levels. You need to determine how much chlorine to use based on the tests. See the following posts for more information:

Nitro's Approach to Water Maintenance

Dichlor/bleach Method In A Nutshell

Chlorine Demand

[RFD100]

My numbers this morning weren't to bad the PH was at 7.2 a TA of 80 a CYA of 32 and CL of at least 10. It was off the chart. I would assume that was because I put in to much dichlor too fast. So will the CL drop off over the next day or so? Would it help to leave the cover off and run the aeration (air injection pump) for a hour or so?

[quantumchromodynamics]

You need the FAS-DPD test kit to determine your chlorine level. It can read above 20 ppm and to 0.2 ppm resolution. That way you can know what your level is, and how fast it is dropping.

The FAS-DPD chlorine test will also allow you to determine if you have combined chlorine. Testing for combined chlorine is very important when using chlorine. When you were on bromine, you didn't need to test for combined bromine.

You can wait for the chlorine to drop on its own, you can add a little bit of hydrogen peroxide to lower it (1 ounce per 1 ppm for 400 gallons), or you can do a partial drain and refill.

I think that you can just wait. The cyanuric acid will moderate the chlorine's reaction rate, so it's not as bad as if you had 10 ppm with no cyanuric acid.

If you have all of the other tests, then you can just buy the FAS-DPD reagents, R-0870, R-0871 and R-0003, and do the test according to the directions here.

Chlorine (Free, Combined) Test

1. Rinse and fill large comparator tube to desired mark with water to be tested.

NOTE: For 1 drop = 0.2 ppm, use 25 mL sample.

For 1 drop = 0.5 ppm, use 10 mL sample.

2. Add 2 dippers R-0870. Swirl until dissolved. If free chlorine is present, sample will turn pink.

NOTE: If pink color disappears, add R-0870 until color turns pink.

3. Add R-0871 dropwise, swirling and counting after each drop, until color changes from pink to colorless.

4. Multiply drops in Step 3 by drop equivalence (Step 1).

Record as parts per million (ppm) free chlorine (FC).

5. Add 5 drops R-0003. Swirl to mix. If combined chlorine is present, sample will turn pink.

6. Add R-0871 dropwise, swirling and counting after each drop, until color changes from pink to colorless.

7. Multiply drops in Step 6 by drop equivalence (Step 1).

Record as ppm combined chlorine (CC).

See the video demonstration here. Go to the bottom of the page and choose the video "To Test (Free and Combined) Chlorine using FAS-DPD [updated 3/5/10]".

You can use thepoolcalculator to calculate the correct amount of chlorine to add.

[RFD100]

Thanks for the input. At this point I think I'LL wait it out. I did order a new test kit yesterday and just have it by the end of the week.

[RFD100]

It's been a week from the refill and I also have a new Taylor K-2006 FAS-DPD test kit. My PH and TA are steady

at 7.5 and 90. My CYA is 30 and my FC is 16 (1 drop = 0.5 ppm, use 10 mL sample). I started with a CH of 150 and now the kit does not register any CH at all. Do I need to add some calcium? Is it possible for calcium to just go away? We have used the tub once last week and the water did not feel as soft as with the bromine. I added 50 ppm of borates per the pool calculator.

Also how much bleach should I add after each soak. It two people for about 20 minutes three or four times per week.

[chem geek]

Doesn't make sense for the CH to not show up at all -- it doesn't go away except from water dilution. So you are saying that after adding the calcium buffer drops and then the indicator dye the CH test immediately turns blue rather than red that you then titrate to blue? Softness of water should be a function of CH and borates, not sanitizer, so not sure why that feels different unless you are soaking with a higher chlorine level (many people have the chlorine be low but measurable at the start of a soak so they don't soak with a lot of chlorine, but then add more afterwards right after the soak).

If you don't have an ozonator, the amount of oxidizer needed for one person-hour of soaking is roughly 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS). So two people for 20 minutes is 2*(20/60) = 0.67 person-hours per day on days you soak so around 1 teaspoon of Dichlor or 3-1/3 fluid ounces of bleach after each soak -- possibly a little more since you need to also carry over for the days you don't soak. However, you should just add enough so that you have a measurable residual at the start of your next soak (1-2 ppm FC if you don't want to soak with chlorine; 4 ppm FC if you want to sanitize with chlorine during the soak, but will smell more of chlorine). If you have an ozonator, the amounts you need to add may be less (possibly half if you were to soak every day; perhaps two-thirds with your soaking about every other day).

[RFD100]

I filled the water to the 25 ml mark. Put in 20 drops of R-0010 and mixed. Added 5 drops of R-0011L mixed, and the water never changed colors to red it just stays clear. This afternoon I pulled out my old HTH 6-way test kit and the CH measured at 160 ppm. From the tap is was 150 ppm. I take it after your up and going you don't worry must about the calcium level.

We also have a ozonator on our Marin. I need to test it and make sure it still works. Bubbles come out but some where I have ozone test kit that goes in line. If it's working naturally it would take a little less bleach.

[chem geek]

Ah, turning to clear is not the same thing as no CH. If there were no CH, it would have simply been blue to start with. If the sample stays clear even after adding indicator dye, then that is some sort of interference. Did you see any tiny floating particles? The interference could be from metal ions. The way to eliminate that interference is to add some drops of the titrant first, say 5 drops and mix. Then you add the 20 drops of buffer, then the indicator dye, then titrant. You then include the initial drops of titrant in your total titrant drop count.

And yes, you don't need to worry about the CH once you've adjusted it initially. It should hardly change before your next refill.