Is Spa Frog Safe At 1-2 Ppm Bromine

[trigear]

Per some recent post regarding the use of silver ions in bromine systems I thought I would ask if this product is safe. Per the spa frog website

http://www.kingtechnology.com/pdf/manuals/Manual-SpaFrogFloating-English.pdf they recommend 1-2 ppm bromine.

Is this a safe level of bromine? Does it matter which type of bromine is used BCDMH VS DBDMH?

[Hillbilly Hot Tub]

Per some recent post regarding the use of silver ions in bromine systems I thought I would ask if this product is safe. Per the spa frog website

http://www.kingtechnology.com/pdf/manuals/Manual-SpaFrogFloating-English.pdf they recommend 1-2 ppm bromine.

Is this a safe level of bromine? Does it matter which type of bromine is used BCDMH VS DBDMH?

This is a safe level because of the silver in the frog, there are other posts that pertain to this also. the frog uses 1-bromo-3-chloro-5,5-dimethylhydantoin, Common Chemical Name: BCDMH,

1-Bromo-3-chloro-5,5-dimethylhydantoin (BCDMH) is a chemical structurally related to hydantoin. It is a white crystalline compound with a slight bromine and acetone odor and is insoluble in water, but soluble in acetone.

BCDMH is an excellent source of both chlorine and bromine as it reacts slowly with water releasing hypochlorous acid and hypobromous acid. It used as a chemical disinfectant used for recreational water and drinking water purification. BCDMH works in the following manner[1]:

The initial BCDMH reacts with water (R = Dimethylhydantoin):

BrClR + 2 H2O → HOBr + HOCl + RH2

Hypobromous acid partially dissociates in water:

HOBr → H+ + OBr-

Hypobromous acid oxidizes the substrate, itself being reduced to bromide:

HOBr + Live pathogens → Br- + Dead pathogens

The bromide ions are oxidized with the hypochlorous acid that was formed from the initial BCDMH:

Br- + HOCl → HOBr + Cl-

This produces more hypobromous acid. However, the hypochlorous acid itself does act directly as a disinfectant in the process

DBDMH is a source of bromine, which is equivalent to hypobromous acid (HOBr).

Br2X + 2 H2O → 2 HOBr + H2X

(Where H2X is 5,5-dimethylhydantoin)

With a pKa of 8.6, hypobromous acid partially dissociates in water:

HOBr ⇌ H+ + BrO-

Hypobromous acid serves as a source of "Br+," which produces bromide ions in the process of disinfection:

HOBr + live pathogens → Br- + dead pathogens

The resulting bromide ions can then undergo oxidation to hypobromous acid in the presence of an oxidizer of sufficient strength e.g. ozone, hypochlorous acid, potassium monopersulfate. This reoxidation process is commonly called "activation" of the bromide ion:

Br- + HOCl → HOBr + Cl-

I think you could use this with the frog, but may have to oxidize frquently to activate the bromine, where BCDMH would more hold its own. Hope this helps some.

[quantumchromodynamics]

The solubilities of DCDMH, DBDMH and BCDMH are about 500 ppm to 2,000 ppm (depending on data source). The bromine and chlorine hydrolyze in water and the DMH is left. DMH is more soluble in water than BCDMH (one reference shows 4,516 mg/l).

http://en.wikipedia.org/wiki/BCDMH

Silver is not compatible with bromine. Due to the low solubility of silver bromide, it is not possible to maintain sufficient silver levels to be effective. Silver levels will typically be in the ppt (parts per trillion) range. 1 ppt = 1 millionth of a ppm.

For example, silver bromide will be at saturation when the bromide level is 10 ppm and the silver level is only 0.000465 ppm = 465 ppt (parts per trillion).

Studies indicate that silver should be in the 20 to 40 ppb (parts per billion) range to be effective.

silver concentrations of 0.02 to 0.04 mg/liter are recommended for sufficient disinfection levels according to in vitro and field studies.

http://www.intec-america.com/resources/Coliform_Bacteria.asp

Note: Silver in drinking water is limited to 100 ppb. There are no studies that indicate that less than ppb levels of silver have any antimicrobial effect.

Maintaining 1 to 2 ppm of bromine is generally safe as long as the level is kept consistent and the level of dimethylhydantoin is limited.

[trigear]

...snip Silver is not compatible with bromine. Due to the low solubility of silver bromide, it is not possible to maintain sufficient silver levels to be effective. Silver levels will typically be in the ppt (parts per trillion) range. 1 ppt = 1 millionth of a ppm.

For example, silver bromide will be at saturation when the bromide level is 10 ppm and the silver level is only 0.000465 ppm = 465 ppt (parts per trillion).

Maintaining 1 to 2 ppm of bromine is generally safe as long as the level is kept consistent and the level of dimethylhydantoin is limited. ...snip

Let me see if I've got this straight.

1. If I shock my tub to 10 ppm any silver over 465 ppt (parts per trillion) will precipitate out and either float to to top or sink to the bottom and be either trapped in the filter or go back into solution as the bromine levels drop.

2. The levels of silver are too low to be useful anyway so the mineral cartridge is a big waste of money.

If this is true then maintaining bromine (with no minerals) is safe at 1 - 2 ppm.

Therefore the recommended levels of bromine are set at a conservative (safe from lawsuit) levels.

[Joe G.]

Per some recent post regarding the use of silver ions in bromine systems I thought I would ask if this product is safe. Per the spa frog website

http://www.kingtechnology.com/pdf/manuals/Manual-SpaFrogFloating-English.pdf they recommend 1-2 ppm bromine.

Is this a safe level of bromine? Does it matter which type of bromine is used BCDMH VS DBDMH?

This is a safe level because of the silver in the frog, there are other posts that pertain to this also. the frog uses 1-bromo-3-chloro-5,5-dimethylhydantoin, Common Chemical Name: BCDMH,

1-Bromo-3-chloro-5,5-dimethylhydantoin (BCDMH) is a chemical structurally related to hydantoin. It is a white crystalline compound with a slight bromine and acetone odor and is insoluble in water, but soluble in acetone.

BCDMH is an excellent source of both chlorine and bromine as it reacts slowly with water releasing hypochlorous acid and hypobromous acid. It used as a chemical disinfectant used for recreational water and drinking water purification. BCDMH works in the following manner[1]:

The initial BCDMH reacts with water (R = Dimethylhydantoin):

BrClR + 2 H2O → HOBr + HOCl + RH2

Hypobromous acid partially dissociates in water:

HOBr → H+ + OBr-

Hypobromous acid oxidizes the substrate, itself being reduced to bromide:

HOBr + Live pathogens → Br- + Dead pathogens

The bromide ions are oxidized with the hypochlorous acid that was formed from the initial BCDMH:

Br- + HOCl → HOBr + Cl-

This produces more hypobromous acid. However, the hypochlorous acid itself does act directly as a disinfectant in the process

DBDMH is a source of bromine, which is equivalent to hypobromous acid (HOBr).

Br2X + 2 H2O → 2 HOBr + H2X

(Where H2X is 5,5-dimethylhydantoin)

With a pKa of 8.6, hypobromous acid partially dissociates in water:

HOBr ⇌ H+ + BrO-

Hypobromous acid serves as a source of "Br+," which produces bromide ions in the process of disinfection:

HOBr + live pathogens → Br- + dead pathogens

The resulting bromide ions can then undergo oxidation to hypobromous acid in the presence of an oxidizer of sufficient strength e.g. ozone, hypochlorous acid, potassium monopersulfate. This reoxidation process is commonly called "activation" of the bromide ion:

Br- + HOCl → HOBr + Cl-

I think you could use this with the frog, but may have to oxidize frquently to activate the bromine, where BCDMH would more hold its own. Hope this helps some.

I have a HotSprings 2010 Grandee with the ACE Chlorine System. Is it save to use a spa frog?

Thanks,

Joe

[quantumchromodynamics]

Let me see if I've got this straight.

1. If I shock my tub to 10 ppm any silver over 465 ppt (parts per trillion) will precipitate out and either float to to top or sink to the bottom and be either trapped in the filter or go back into solution as the bromine levels drop.

2. The levels of silver are too low to be useful anyway so the mineral cartridge is a big waste of money.

If this is true then maintaining bromine (with no minerals) is safe at 1 - 2 ppm.

Therefore the recommended levels of bromine are set at a conservative (safe from lawsuit) levels.

The solubility of silver is dependent on the level of bromide, not bromine.

If you add 0.5 ounces of sodium bromide per 100 gallons on fill up, that starts you out with 16 ppm bromide. That means that a silver level of 291 ppt (parts per trillion) will saturate the water with silver bromide. For every 10 ppm of bromine that you add from bromine tabs, your bromide level will increase by 5 ppm.

The solubility product (Ksp) of silver bromide is 5.4 × 10^-13, which is very low. The solubility product is the product of the molar concentration of silver x the molar concentration of bromide.

107,868 ppm of silver = 1 mole per liter of silver (1M)

79,904 ppm of bromide = 1 mole per liter of bromide (1M).

________________________________________________

Example

10 ppm of bromide = 1.2515 x 10^-4 moles per liter

5.4 x 10^-13 = (1.2515 x 10^-4M)(molar concentration of silver)

The molar concentration of silver is 4.3148 x 10^-9M

The concentration of silver in ppm is 4.65 x 10^-4 ppm, which equals 465 ppt.

_____________________________________________________

On startup, your level of bromide will be 16 ppm, which will limit the silver concentration to 291 ppt.

The concentration of silver is too low to do any good. All other silver ion products specifically say that their silver ion product is not compatible with bromine/bromide.

I recommend a minimum level of bromine of 1.0 ppm at all times. Note: This is not a target level, it's just a minimum.

I recommend that you maintain about 2.0 ppm to 3.0 ppm on startup, about 2.5 ppm to 3.5 ppm after 30 days of using tabs, about 3.5 ppm to 4.5 ppm after 60 days of using tabs, and that you change the water at least by 90 days.

The progressively higher levels of Total Bromine are to help compensate for the increasing levels of dimethylhydantoin from the tabs. Periodic shocking with regular, unscented 6.0 % bleach or MPS can help eliminate any bromamines that might have accumulated. Since there is no readily available test for bromamines, you should carefully monitor your bromine demand and compensate accordingly.

[quantumchromodynamics]

I have a HotSprings 2010 Grandee with the ACE Chlorine System. Is it save to use a spa frog?

Thanks,

Joe

No, metals should not be used in a salt system. Also, the high levels of chloride will limit the silver concentrations to less than 1 ppb. A salt level of 3,000 ppm will limit the silver concentration to 372 ppt (parts per trillion).

Ksp = 1.77 x 10 ^-10 silver chloride

http://www.wolframalpha.com/input/?i=ksp+silver+chloride

35,453 ppm of chloride is 1M

1.77 X 10 ^ -10 = (0.05133M)(molarity of silver)

35.453/58.443 = 60.66 % chloride

3,000 ppm of sodium chloride = 1820 ppm chloride

1820 ppm chloride =0.05133 M

3.448 x 10^-9 M silver = 3.72 x 10^-4 ppm = 372 ppt (parts per trillion)