Low Head Oxygenation (LHO)

A direct ratio exists between the amount of oxygen in your system’s water and the quantity of fish you can raise. More oxygen and fish translate to increased profits for your operation. The Low Head Oxy-generator (LHO) injects oxygen into your system’s water effectively and efficiently stripping nitrogen at the same time. The LHO is up to 95% efficient and does so without moving parts or electricity. The cost of oxygen is the only consumable operating expense. That’s a plus for you, you get economy and “fail safe” operation.

Water Temperature Charts

Flexible Design

Two models are available. Designed to fit in raceways and head boxes the original LHO is rectangular and fabricated in stainless steel or fiberglass. The newer round style LHO is more suited to recycle applications and is fabricated in fiberglass. Specify that you wish to employ the LHO as an oxygen/ozone injection device and WMT can fabricate the LHO in a glass reinforced vinylester which is ozone tolerant. A flexible device, the LHO can be tailored to your specific application.

LHO efficiency or how much oxygen is absorbed into solution is referred to as absorption efficiency. Available head combined with oxygen and water flow rates determine LHO absorption efficiency. Required oxygen flow rate is determined from biomass loadings, feed rates, and influent and effluent DO levels. If you fill out an Oxygen Supplementation Data Sheet, we can design an oxygen injection system for your facility. Our computer design program pinpoints LHO performance.


  • No Movint Parts
  • No Electricity Required
  • Predicted and Guaranteed Results


  • Removes N2 gas from the water as oxygen is added
  • Does not increase total gas pressure
  • Maintaining DO levels enhances fish health and water quality
  • No mechanical moving parts - no electricity
  • Minimal capital investment
  • Simplicity - ease of installation and maintenance

When employing the LHO, the cost of oxygen is the only consumable operational expense. Electrical power is not required which provides a dual benefit of economy and ”fail safe” operation. Application of oxygen must be accomplished in the most efficient manner without loss, keeping production costs to a minimum.


WMT holds the most experience in applying LHO technology with over 300 installations in 8 years. Our team of specialists can assist you in determining how best to source oxygen: bulk vs. generated.

The WMT LHO will provide the exact DO level desired for a given installation while maximizing the absorption efficiency. 12 years of research and investment in development of the LHO enables WMT to tailor the unit to specific site requirements. This yields cost effectiveness and maximum profits for the producer.