730 Bubbler Flow Module

Bubbler level sensing provides the most accurate measurement.

730 Bubbler Flow ModuleTeledyne ISCO 730 Bubbler Flow Modules use an internal air compressor to force a metered ​amount of air through a bubble line submerged in the flow channel. By measuring the pressure needed to force air bubbles out of the line, the water level is accurately determined. The 6712 Sampler then converts this level into flow rate. 

The 730 provides accurate measurement in a variety of conditions. It is suitable for small channels, and is not affected by wind, steam, foam or turbulence. And, because only the bubble tube contacts the flow, corrosive chemicals are not a problem. Automatic bubble line purging prevents clogging. The 730 also resists damage by lightning and debris, making it ideal for stormwater applications. 

Automatic Drift Compensation makes Teledyne ISCO bubbler flow meters the most accurate level measurement technology. In standby applications such as stormwater runoff monitoring, Automatic Drift Compensation also allows the 730 to maintain calibration for extended periods in standby applications such as stormwater runoff monitoring.


When you purchase instruments from Teledyne ISCO, you not only receive innovative, high quality products, you also receive excellent customer service and product support. Your initial purchase is only the beginning of Teledyne ISCO's ongoing commitment to their customers.


Teledyne ISCO Water & Wastewater Product Guide
Isco 730 Bubbler Flow Module DatasheetDatasheet
Isco Stormwater Monitoring GuideOther
Sampler Selection Guide (2014)Other
Sampler Source BookOther
730 Bubbler Module User ManualUser Manual


​​​​​​​​​​​​​​​​​​​​​​730 Bubbler Flow Module

Size (HxWxD): 4.9 x 5.7 x 2.0 in (12.4 x 14.5 x 5.1 cm)
Weight: 1.1 lbs (0.5 kg)
Material: Polystyrene
Enclosure: NEMA 4X, 6 IP67
Power: 9 to 14V DC (provided by 6700 Series Sampler)
Program Memory: Non-volatile, programmable flash; can be updated via interrogator port on 6700 Series Sampler using a PC
Operating Temperature: 32° to 120°F (0° to 49°C)
Storage Temperature: 0° to 140°F (-18° to 60°C)


Range: 0.1 to 10 ft (0.03 to 3.05 m)
Level Measurement Accuracy (Non-linearity, repeatability, and hysteresis at 25°C (77°F). Max error (±) for indicated level range. ​
0.1 to 5.0 ft (0.03 to 1.52 m): ±0.005 ft (±0.002 m)
0.1 to 7.0 ft (0.03 to 2.13 m): ±0.01 ft (±0.003 m)
0.1 to 10 ft (0.03 to 3.05 m):
±0.035 ft (±0.011 m)
Temperature Coefficient (Maximum error (±) per degree of temperature change over compensated range) ​
For level in feet: ±0.0003 x level x temperature change from 72°F
For level in meters: ±0.0009 x level x temperature change from 22°C
Automatic Drift Correction: After a 5 minute warm-up period, zero level is corrected to ±0.002 ft. (±0.0006 m) at intervals between 2 and 15 minutes
Long-Term Level Calibration Change: Typically 0.5% of reading per year
Ambient Operating Temperature Range: 0° to 140°F (-18° to 60°C)
Compensated Temperature Range: 32° to 140°F (0° to 60°C)

​For a full list of product specifications, see the datasheet.




Standard Features

  • Bubbler line is unaffected by flow stream composition.
  • Automatic Drift Compensation provides high accuracy and maintains calibration in standby applications such as stormwater monitoring.
  • Built-in flow conversions for most applications, including weirs and flumes, Teledyne ISCO flow metering inserts, Manning formula, data points, or equation for special situations.
  • During the program’s operation, current flow and level values are viewable on the sampler's LCD display.
  • All level data stored in the sampler is available for later retrieval, reporting, and graphing using Teledyne ISCO Flowlink® software.


  • Level and flow measurement in shallow streams, and/or where lightning and debris may occur
  • Triggering the 6712 sampler based on flow or level.
  • Collecting flow proportioned samples.
  • Treatment capacity analysis
  • River and stream gauging

Options and Accessories

  • Stainless steel bubble line extension
  • Bubble line carrier and mounting rings for installation of bubble line in round pipes from 6 to 15 inches in diameter
  • Scissor rings for installation in round pipes from 18 to 60 inches in diameter
  • Metering inserts with attachable V-notch weir for street-level installation of bubble line in round pipes from 6 to 12 inches in diameter. ISCO Metering inserts are ideal for short-term (a few hours) or long-term (several months) flow studies.​