Dissolved oxygen room study · 26 tanks
What actually controls oxygen in a shrimp tank?
We compared plant cover, water movement, bubblers, fluffy algae and livestock across the whole room. The results challenged several assumptions—and produced one excellent Vallisneria surprise.
Room temperature: approximately 22°C. Individual water temperatures were not measured.
Highest reading8.4mg/L · Platy/Vallisneria tank≈96% estimated saturation at 22°C
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How we classify each reading
Every boundary belongs to only one category. Exactly 5.0 is Acceptable; exactly 7.0 is Good.
What the room showed
Five findings worth taking forward
These are associations from one room and one test session—not proof of cause and effect.
Surface cover was not the oxygen killer we expected
Even near-complete duckweed and floating-plant cover could coexist with good readings. Shrimp-only surface cover had almost no relationship with dissolved oxygen.
r = +0.11 · shrimp-onlyWater movement mattered
Strong circulation was associated with higher oxygen and also helps move waste towards the filter.
r = +0.46Bubblers helped differently
No notable oxygen boost appeared, but better circulation can improve filtration and keep tanks cleaner.
r = −0.14Fluffy algae was a warning signal—with caveats
Explicitly affected tanks tended to read lower, but the subset was small and observer bias is possible. The algae may be a symptom rather than a cause.
r = −0.65 · 11 coded tanksThe Vallisneria tank reached near saturation
At a likely 22°C, 8.4 mg/L is approximately 96% oxygen saturation: high compared with the room, but safe and close to normal full saturation. Visible pearling makes this an excellent replication target.
8.4 mg/L · ≈96% saturationShrimp-only sensitivity check
Which factors moved with oxygen?
Pearson correlation runs from −1 to +1. Values near zero show little linear relationship.
Surface coverHeavy floating cover did not reliably mean lower oxygen in these shrimp tanks.
+0.11Very weak
Water movementStronger circulation was the clearest positive pattern in shrimp-only tanks.
+0.46Moderate positive
Fluffy algaeInteresting, but based on 11 explicitly coded tanks and vulnerable to observer bias.
−0.65Strong negative
Bubbler presentNo notable oxygen lift; bubblers may still improve circulation and waste capture.
−0.14Very weak
Tank-by-tank evidence
Explore all 26 readings
Filter the room, sort the readings, then open any tank for the observations recorded in the transcript.
26 tanks shown
Best next experiment
Can the Vallisneria result be repeated?
Measure the same tank at three points in the lighting cycle while recording the actual water temperature, surface movement and visible pearling. Repeat on several days before drawing a conclusion.
- 01Before the lights come on
- 02Halfway through the light period
- 03Immediately after lights-out
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What this study can—and cannot—say
A useful room survey finds leads. It does not replace controlled repeat measurements.
Each tank was measured once during the same practical room survey.
The room was approximately 22°C; individual water temperatures were not recorded.
Tank size, age, stocking, plants, substrate, feeding and filtration all differed.
A relationship can identify a useful lead without proving what caused it.
Sources, measurement notes and data corrections
The Milwaukee MW600 was calibrated before the session and readings were allowed roughly one minute to settle. For a polarographic probe, gentle consistent water movement and a bubble-free membrane matter.
Room temperature was approximately 22°C. Water temperature was not measured separately, so the Vallisneria saturation figure is an estimate.
YouTube repeated “Tank G” twice. Alphabetical context indicates those records were Tank J and Tank Q; both remain flagged in the spreadsheet.
Reference: US EPA dissolved oxygen guidance.