At .1 mg/l PO4 I wouldn't worry about it, it's in hte range corals see in the wild. FWIW
.03 mg/l is the minimum, .2 is what corals are exposed to with upwelling,
.5 mg/l may be acceptable acceptable and even
.9mg/l might not be an issue and at the beginning of his presentation in this
video RIch Ross talks a little bit about his acro dominate system sitting at 1.8 mg/l. I would on the other hand try to keep nitrates low as there is a mountain of research showing nittrates are not good for corals. I'm well aware some have kept corals at very high nitrate levels but just because some have been successful at acclimating cotrals to high levels doesn't mean it good for them.
Here's
fig. 3 from this paper reviewing almost 4 dozen previosu research papers
Sorry for the data bomb but here's some additional links on phosphorus and nitrogen if you're intereste
d:
Nitrogen Stuff
Ammonium Uptake by Symbiotic and Aposymbiotic Reef Corals
www.ingentaconnect.com
Amino acids a source of nitrogen for corals
SUMMARY. This study was designed to assess the importance of dissolved free amino acids (DFAA) as a nitrogen source for the scleractinian coral Stylophora pistillata. For this purpose, experiments were performed using 15N-enriched DFAAs, and %15N enrichment was measured both in animal tissue and...
journals.biologists.com
Urea a source of nitrogen for corals
Urea can be one of the major sources of nitrogen for phytoplankton, but little is known about its importance for corals. Experiments were therefore de…
www.sciencedirect.com
Diazotrpophs a source of nitrogen for corals
Corals are mixotrophs: they are able to fix inorganic carbon through the activity of their symbiotic dinoflagellates and to gain nitrogen from predation on plankton and uptake of dissolved organic and inorganic nutrients. They also live in close association with diverse diazotrophic communities...
pubmed.ncbi.nlm.nih.gov
Context Dependant Effects of Nutrient Loading on the Coral-Algal Mutualism
Labile dissolved organic carbon (DOC) is a major pollutant in coastal marine environments affected by anthropogenic impacts, and may significantly con…
www.sciencedirect.com
Phospahte Stuff
ttps://www.cambridge.org/core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom/article/an-experimental-mesocosm-for-longterm-studies-of-reef-corals/AFB1CF4CB68823BD13AD254623FD3C7C#
An Experimental Mesocosm for Longterm Studies of Reef Corals
Phosphate Deficiency:
Nutrient enrichment can increase the susceptibility of reef corals to bleaching:
Increased dissolved inorganic nitrogen (DIN) concentrations in sea water have been linked to a reduction of the temperature threshold at which corals bleach, however, the mechanism underlying this change is not known. This phenomenon is now explained in terms of increased phosphatase activities...
www.nature.com
Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:
Reef building corals associated with symbiotic algae (zooxanthellae) can access environmental nutrients from different sources, most significantly via the up...
www.frontiersin.org
Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
Enrichment of reef environments with dissolved inorganic nutrients is considered a major threat to the survival of corals living in symbiosis with din…
www.sciencedirect.com
Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach
Phosphate contamination can negatively affect corals, modifying growth rates, skeletal density, reproduction, mortality, and zooxanthellae. We determi…
www.sciencedirect.com
High phosphate uptake requirements of the scleractinian coral Stylophora pistillata
SUMMARYSeveral untested aspects of the regulation of inorganic nutrient uptake were examined using nutrient depletion experiments with the symbiotic coral Stylophora pistillata. The total inhibition of phosphate uptake in artificial seawater lacking sodium indicates the involvement of a...
jeb.biologists.org
Phosphorus metabolism of reef organisms with algal symbionts
therichross.com