
Nitrate and Phosphate Removal by a UAS Algae Box in a 20 L System
A UAS algae box — an enclosed algae scrubber with internal algae screens and its own LED lighting — was run against a no-box control in matched 20 L tanks for one week. Nitrate in the treatment tank fell from 10.8 mg/L to 5.8 mg/L, about 46%, while the control drifted between 9.5 and 11.2 mg/L with no downward trend. Phosphate fell much faster, from 0.63 mg/L to 0.06 mg/L within a day, then drifted back up to 0.18 mg/L mid-week before easing to 0.09 — most likely phosphorus released as algal debris and surface deposits broke down. The practical consequence is that the screens have to be harvested on a schedule: left to accumulate, the box begins returning nutrients it removed earlier. One treatment tank and one control, six sampling points across seven days, and a single pump flow of 265.6 L/h — trend data, not a validated removal rate.
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