Phosphates can be a pain the ole sump! Zero phosphates are no good but too much and you have a problem! Ewww algae! So let's talk today about how the masses are keeping phosphates under control!
This assumes phosphate will cause problems! Phosphates or phosphorus availability? What are the problems which may be caused by "too much" inorganic phosphates?
What is "too much"?
What is the effect of the phosphate level on algae growth compared with the nitrogen source used? May phosphorus be the limiting factor for algae growth?
I think it will be a combination of all parameters and not only phosphorus. What may be the effect of removing phosphate without taking into account all other essential nutrients?
It has been shown coral bleaching is caused due to phosphorus starvation during a period of increased growth ( temp?) supported by high nitrogen availability. (high N/P ratio?)
It has been shown increased phosphorus availability supports coral calcification and influences coral density but is not harmful to coral growth. ref:
http://www.baharini.eu/baharini/doku.php?id=nl:makazi:chemie:calcificatie
Phosphate is produced by heterotrophic remineralization.
Removing phosphorus by assimilation, by harvesting slow-growing algae, prevents nutrient starvation as heterotrophic remineralization is faster as autotrophic assimilation and is my favorite. The removal can be estimated.
Chemical phosphorus removal may cause nutrients to unbalance and is only advisable if active controllable, in a reactor or refuge. It may create phosphorus starvation if not active-controlled.
Bacterial phosphorus assimilation due to organic carbon addition completely messes up the nutrient availability in the system and does not remove a thing. It may be back as fast as it is used. The influence on the normal remineralization rate, based on the natural demand for organic carbon, and the availability of essential nutrients for slower-growing organisms? The effect on the total carrying capacity based on the ammonia removal rate? And a lot more.
If dosing is based on the nitrate level the cure may become a lot worse as any problem which may be caused by the presence of phosphate. The same can be said for nitrate.
The production and reuse or harvesting bio floc in a refuge, without influencing the C/N ratio in the main system, is another application of biological nutrient management. ref:
http://www.baharini.eu/baharini/doku.php?id=nl:makazi:het_water:filtratie:biofloc&rev=1578596964
A skimmer removes only max +- 35% DOC and TOC, and does this very selective, leaving the same kind of waste behind. It may prevent phosphate production due to preventing remineralization but will not prevent nitrogen and phosphorus accumulation as it constantly removes building materials needed to prevent the accumulation of inorganic nutrients.
When phosphate becomes a problem? A problem needing action? Normal biological nutrient management does not restore imbalances created by filtration. Often the method used to correct nutrient levels has a lot bigger impact on the system as the nutrient level ever will.
Increased phosphate and nitrate levels show something is preventing growth or and abnormal high remineralization has or is taking place. The content of a dead fish may lead to a lot of algae growth. If the fish is not removed in time one must harvest algae. As the remineralization rate of heterotrophs may be a lot higher as the assimilation rate of photo-autotrophs, nitrate and phosphate will accumulate. Must this phosphate be removed or do we wait until nature does what it has planned? Will nature be able to act as planned in a system with a skimmer?
Often increased phosphate availability is the result and not the cause and correcting the availability without looking any further may increase the problem instead of solving it. Of course, when it is really going wrong due to messing with natural processes, the phosphate level will always be there to take the blame.
Phosphate levels as present in a reef aquarium do not kill, exempt if phosphorus is not sufficiently available.
What is the relation between inorganic phosphate measured in the water column and the availability of usable phosphorus?