FDA 510(k)

The TANGO3 Water Storage Tank with Ozone Disinfection System has been assigned FDA 510(k) 093641

Tango3 News
Tango3 News Bulletin


We are pleased to inform you that the FDA has cleared 510(k)140984 for TANGO3 to include a change in the indications for use that takes advantage of the ability to set the disinfection cycles differently for each day of the week with software revision 2.7.  The new IFU reads as follows:

The TANGO3 Water Storage Tank with Ozone Disinfection System is intended to be used for disinfection of the water distribution system of a dialysis facility. The tank of the TANGO3 is also used as the water holding tank of the distribution system. The disinfection process is completely automated. Ozone concentration during disinfection is between 0.2 ppm and 0.3 ppm. Weekly disinfection cycles should be for four periods of 30 minutes with adequate water flushes between them and after the last cycle. In addition to the weekly disinfection cycle, a 45 minute disinfection cycle with at least two rinse cycles may also be performed multiple times weekly for additional reduction of bioburden as determined by user facility monitoring.   At the end of disinfection, the distribution loop will have less than 0.1 mg/l. (0.1 ppm) of ozone, in accordance with AAMI/ISO 26722:2009 (



Semi-Annual Maintenance no longer requires the ozone probe to be rebuilt.  After a difficult and frustrating period maintaining polarization, we worked with our supplier of membranes and he determined their raw materials were not within specification.  Subsequent correction of their validation procedures for raw materials has increased reliability significantly.  Monthly accuracy checks and calibration will best determine when repolarization is required.



Biofilm Reduction and Removal      Although any measures taken to prevent proliferation of microorganisms will also help to reduce the formation of biofilms, ozone is the only disinfectant that has demonstrated the capability of reducing biofilm that is present in a water treatment system within a reasonable time frame with ozone levels employed by the TANGO3 system. TANGO provided a number of independent studies to FDA in support of this claim.  The best hard evidence, however, came from our own research briefly described below:

TANGO3 used Acidovorax facilis, Pseudomonas aeruginosa, and Burkholderia cepacia to facilitate growth of biofilm in a real plumbing system exactly as found in a dialysis facility except for the removable sections and dialysis machine terminals.  The three microbes were inoculated into the system 3 times a week for 4 weeks to allow ample time for biofilm formation.  “A copious biofilm was clearly evident by visual observation of the internal surfaces, and was confirmed microbiologically.”

Seven disinfection cycles with ozone were then conducted.  Because the plumbing design had sections that could be removed, one section was removed after each ozone cycle.  There were 2,080,000 CFU’s/cm2 before the first cycle (run).  After the first cycle, 3 CFU’s were isolated.  After the second cycle 12 CFU’s were isolated.  No bacteria were detected after cycles 4 – 7.    Initial biofilm levels of 10,722cfu/cm2 and 13,378 cfu/cm2 were reduced to none.

Following the above tests, normal use simulation was done for two weeks without the use of ozone.  At the end of the two week period, there was no evidence of bacteria present.  Again, one cycle of ozone reduced CFU’s below action levels (50 CFU’s) even though the protective biofilm barrier had a substantial presence.

What About Heat?

The clinical consequences of the present study remain to be elucidated. Nevertheless, it should be mentioned that biofilm, once formed, is notoriously difficult to remove [Fig.3].  Moreover, biofilm formation may be extended beyond the water treatment system into the dialysis module [Fig. 2].  In a recent study, neither heat nor chemical disinfectants were able to eliminate biofilm, which was formed by contamination of a dialysis monitor with P. aeruginosa (abstract Di Felice et. al. Blood Purifi 20:504, 2002).  Thus, it appears prudent to reduce biofilm formation as much as possible.”

What About Speed of Action?

Possibly the strongest support for ozone is found in the EPA Guidance Manual Alternative Disinfectants and Oxidants 1999

Section 3 of the Manual discusses ozone thoroughly.  Of all the disinfectants and oxidants discussed in the Manual, not one is mentioned as being superior to ozone.  There are numerous mentions of ozone being compared to other alternatives for use against bacteria, fungi and viruses.  Selected quotes are in italics, with the location of the quote provided as well as possible. Disinfection     (For brevity, one example)

“Ozone is a powerful oxidant able to achieve disinfection with less contact time and concentration than all weaker disinfectants, such as chlorine, chlorine dioxide, and monochloramine (Demers and Renner, 1992).

This is supported by our research at TANGO3        This is best demonstrated by Attachment 21A which shows that the bioburden in the storage tank was reduced from Too Numerous to Count (TNTC) to 4 Colony Forming Units (CFU’s) in 20 minutes, and the ozone level was 0.0 ppm.  The second test, with the distribution pump running, is highlighted in yellow on page 5, and demonstrated that CFU’s that were TNTC were reduced to Zero after 20 minutes and the ozone level was still 0.0 ppm.  Ozone has been described as similar to a bomb that destroys itself as it destroys its target.

The following statement summarized our data submission to FDA

Although ozone is clearly faster acting and more effective than chlorine and peracetic acid, predicates – used for 510(k)093641 -- that require only 30 minutes of disinfection time, because of TANGO3’S failure to specify one disinfection cycle in the Indications for Use for 510(k)093641, TANGO3 finds it necessary to resubmit all of the original test data with emphasis on the results after one 30 minute disinfection cycle of ozone.  Note that the bioburden level in each of the tests conducted by TANGO3 was extreme – unlikely to ever be experienced in any active dialysis center.  The evidence is conclusive enough that additional testing could only be considered an extravagant waste of resources. 

The references cited above (listed in Attachments 21A and 21B) independently verify that ozone is both the most effective and fastest acting agent available to the water treatment industry for disinfection of water systems.  


Technical Support:    Fred Spencer   502-722-5615

Sales:   Amanda Cape 502-722-5615

Microorganisms Killed by Single Cycle of Ozone

Microorganisms Killed by Single Cycle of Ozone*


Maximum Bioburden

Cycle Time



11,000.000 CFU

30 minutes

None detected

Pseudomonas Aeruginosa. and Burkholderia Cepacia

18,000,000 CFU

30 minutes

None detected

Brevundimonas Diminuta

4,000,000 CFU

30 minutes

None detected

Mycobacterium Fortuitum

5,200,000 CFU

30 minutes

None detected


Aspergillus Fumigatus **

1,150,000 CFU

30 minutes

None detected

Candida Tropicalis

44,000,000 CFU

30 minutes

None detected


Poliovirus type 1

550 Log10TCID50/mL

30 minutes

None detected


550 Log10TCID50/mL

30 minutes

None detected

Herpes Simplex Virus Type 1

750 Log10TCID50/mL

30 minutes

None detected


*Multiple tests were conducted for each organism.  The results in the table demonstrate the maximum bioburden in each test except for Aspergillus fumigatus.  All other organisms resulted in “None detected” in every test.

**Five (5) tests were conducted for this fungus.  Two of the tests did show a 30 minute cycle was not sufficient to completely eliminate the bioburden.  One of those had 1,200,000 CFU’s at the beginning of the test.  The other one had 810,000 CFU’s .  The bioburden caused the water color to be black to charcoal black, but appeared normal at the end of the 30 minute cycle.