Oxygen Generator Fishing – PSA Type

WEBPAGE UPDATED                            Tuesday  June 22, 2022


FishO2™ livewell oxygen generator, distributed by T-H Marine and Keep A Live bass boat oxygen system, makes 90% oxygen with pressure swing absorption (PSA) technology, new . The oxygen concentration falls in proportion to use.

TRIVIA – PSA Medical Oxygen Generators: FishOx Systems, Inc., was founded with 30 years of experience in the medical oxygen respiratory field.

The “FishOx” fish oxygen concentrator for baitfish, fishing and more was the precursor to the “FishO2” PSA oxygen generator now sold by T-H Marine and KeepALive – https://www.landbigfish.com/articles/default.cfm?ID=2102

The FishOx buzz-phrase was, “Keep Your Catch Alive, with oxygen.” This was a brilliant modification of Ray Scott, Founder of B.A.S.S. buzz-phrase, “Don’t Kill Your Catch.”

Enter: Fish O2™ Oxygen Generation System: $995.00. T-H Marine who has taken the same medical technology used in hospitals to generate pure (90%) oxygen and adapted it to keep your catch or bait alive and healthy.

FishO2™ is a livewell oxygen system, a PSA (pressure swing absorption type) oxygen generator. http://en.wikipedia.org/wiki/Pressure_swing_adsorption

FishO2™ requires electricity, D/C batteries. It is very similar to PSA medical oxygen generators sold and leased by Durable Medical Equipment companies and Home Health Agencies. This noisy little unit will produce some oxygen too. The dose, volume and concentration of oxygen you may need is NOT adjustable; you have no choice here. The machine is either off or on as long as your battery lasts. The outlet pressure is low at preset 10 psi and is not back pressure compensated. A giant pore air stone diffuser is necessary with minimal operational pressure to produce bubbles.

Hot gases: PSA generators entrain ambient air at ambient air temperatures. Air temperature can exceed 100 F. in the summer. Inside the unit ambient gas temperature is elevated even higher because the electric motor/air compressor inside the sealed housing runs continuously producing additional mechanical heat. Because the gas delivered to livewell water is hotter than ambient air temperature, expect your livewell water to be really HOT in the summer, always hotter than air temperature.

An encased 12 volt electrical air compressor/motor pumps room air through canisters of packed hygroscopic (the tendency of a material to absorb water and having the characteristic of drawing moisture from the atmosphere) Zeolite sieve beads. New and dry Zeolite beads can filter out some nitrogen and deliver near 87% oxygen in limited small volumes only when the unit is brand new. PSA generators deliver various concentrations of mixed gases; they do not deliver pure oxygen. When Zeolite sieve becomes saturated with water vapor, delivery oxygen concentration falls precipitously, sieve beds stop-up, gas flow occludes and maintenance is required. Zeolite canisters must be replaced or the Zeolite must be taken out of the canister and regenerated.

The volume and concentration of oxygen delivered to the livewell is limited and cannot be controlled by the fisherman.

Molecular filtering efficiency and outlet oxygen concentrations degrade rapidly when used on boats, specifically when used in warm high relative humidity environments.

FishO2™ does not come with an air dryer on the inlet side of the air compressor which is a problem when used on the water. Inline air dryers eliminate relative humidity problems and extend the live span of sieve beads hundreds of hours. Air dryers reduce incidents of catastrophic system failure.

Factory maintenance is required when FishO2™ is not working properly. Expensive testing and diagnostic equipment is commonplace at the factory.

Fishermen do not need expensive oxygen testing equipment to know if a problem in the livewell is real. The bait or mature tournament fish in the livewell “speak in terms of behavior” to the fisherman, some dead some dying. When water quality is great, bait should behave and look like guppies in your 10 gallon square home aquarium, no foamy dirty water that stinks.

Whenever the dissolved oxygen concentration is insufficient, unsafe and the suffocation begins, the bait behaves like it’s in an aerated livewell or bait tank at 10 AM in July / August… floating dead, piping at the surface, stacking in corners, red-nosed, sloppy, lethargic, dying, dead foam on livewell water surface, water stinks… you know the signs. Watch your bait or tournament gamefish in the livewell. Bait and fish will behave exactly like they did in summer in your aerated livewell when the oxygen levels are low: sickly, red-nose, red belly, dying and dead.

This PSA generator has a very low outlet pressure which can be problematic when used with oxygen diffusers, micro-bubble air diffusers and small-bore oxygen tubing. Many bubblers will not bubble because of the low outlet pressure, water column head pressure and water density. many tyhttps://en.wikipedia.org/wiki/Gas_bubble_diseasees of gas diffusers are ineffective because of the low outlet pressure (10 PSI).

Be aware of this problem when using any PSA oxygen generator that delivers oxygen concentrations less than 100% pure (90% oxygen, 10% air/nitrogen), 10% nitrogen under pressure is the problem gas. Entraining PSA generated mixed gases through a livewell water pump venturi device will result in nitrogen supersaturation. Nitrogen pressurized (greater than barometric pressures) through a venturi device can cause very serious fish health problems. If your livewell goal is improving fish health and survival in your summer livewell water… nitrogen gas supersaturation is the cause of tissue emphysema, gas bubble disease, bends, additional livewell stress must be expected with PSA oxygen generators when the PSA generator gas is delivered into livewell water with water pump/venturi devices.

Ten percent (10% Nitrogen @ < than 10 PSI in livewells/bait tanks is a PROBLEM:

Nitrogen Gas Bubble Disease –  https://en.wikipedia.org/wiki/Gas_bubble_disease

FishO2™ PSA generators have many small delicate moving parts: valves, switches, constant noise, constant heat and constant vibration. The air compressor motor runs continuously, the compressor motor does not cycle on and off.

PSA generators have internal switching valves that dump nitrogen and deliver oxygen intermittently to different internal canisters. When working correctly, it may sound like the generator is turning on and off and may give you a false impression of conserving electricity between cycles.

Ninety percent  (90%) of the nitrogen gas is filtered from the air, dumped and returned to the atmosphere. Ten percent (10%) of the nitrogen and 90% of the oxygen is conserved in a small internal gas reservoir then pumped to the livewell at very, very low pressures. Giant pore air stones or venturi devises are recommended by the manufacturer because of the low PSA generator outlet pressure and the fisherman inability to adjust the generators gas flow.

FishO2™ is a low pressure oxygen system capable of producing oxygen enrichment. Oxygen gas safety is often discounted as menial and not important, or worse, oxygen safety is never mentioned at all.

Oxygen-enrichment (24% oxygen or greater)  is oxygen-enrichment regardless of the source of oxygen gas and there are safety issues that must be considered. It makes no difference whether the oxygen comes from an Oxygenator™,  PSA generator, pressurized oxygen cylinder or liquid oxygen cylinder, the “Rules of the Oxygen Road” apply. Some sales people recommend entraining PSA generated oxygen into the intake side of a bilge pump or livewell pump located inside or outside the livewell. That recommendation is unsound and dangerous, that is an oxygen FIRE HAZARD

CAUTION – Water pumps, Bilge Pumps and Oxygen: Rule, Inc., Jabsco, Xylem, Atwell, Johnson, Dannco and other livewell / bilge pump manufacturers DO NOT recommend entraining oxygen-enriched gas (24% oxygen or greater)  through venturi devices located up stream directly into their pumps.

Their pumps are ignition protected to ISO 8846 for use in fuel/air environments like boat bilges. None are ignition protected nor certified for use with pure oxygen or oxygen enriched environments. FIRE HAZARD

Environments with High Relative Humidity, on boats: When PSA generators are used in high relative humidity environments with out  internal air dryers installed; electrical switches, pneumatic valves and clogged sieve beads are problematic, common and require maintenance, Expect these problems with this oxygen generator when used in high humidity marine and freshwater fishing environments.

Within only a few months of use the Zeolite sieve beads become saturated with ambient humidity causing the outlet oxygen concentration to fall dramatically from 90% O2 when new.

Expect these problems: Additional livewell heat from hot gas, noise, vibration, limited /unstable doses, gas volumes and concentrations, low gas delivery pressures, low variable gas flows and the potential for catastrophic internal electrical or gas plumbing failure is high. Expect additional livewell problems, failures and repair cost.

Know the Hidden Cost: Always ask the salesman about all the hidden cost of PSA generator operation including required maintenance, repair and return shipping to the manufacturer or dealer. This unit must be returned to T-H Marine for all maintenance, repair and adjustments. Before you purchase a PSA oxygen generator find out how much it will cost you to replace or rebuild the air compressor, electrical switches or to replace Zeolite sieve beds. This unit cannot be repaired on the boat. If you open the unit housing your warranty is VOID. Cost $750.00