As mentioned above I would double check the test kits with a that big of a change in that short of time. Also there's this:
2657円まるいち 博多辛子明太子(無着色) 「博多の華」 (ギフト用) 180g Z6572海産物イクラ,タラコ,魚卵 Qoo10] 「博 まるいち 博多辛子明太子(無着色) | therichross.com
therichross.com
And if you want to dif into some of the research done on corals in aquariums there's these peer reviewed papers:
An experimental mesocosm for long-term studies of reef corals - Volume 92 Issue 4
www.cambridge.org
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