The graph bellow shows the absorption time behaviour for the most of absorbers (sorbents), which is rather problematic for bellow mentioned reasons:
P1 Time Period - Immediately after the new absorber is applied the absorption rate hits the ceiling and is higher than needed. Zero phosphorus concentration is undesirable - trace phosphorus concentration in seawater is required - more information can be found in related article about phosphorus. Many absorbers also release unwanted matter - often toxic (orange area) - causing sometimes pH value changes as well.
P2 Time Period - In the course of certain time the absorption rate is optimal - phosphorus concentration is held on trace level.
P3 Time Period - From certain moment absorption rate falls gradually. The logical economical dilemma arises - when to proceed with absorber exchange? Particularly at this time period the absorber can also be colonized by various bacteria and if kept too long time in a tank, unwanted biological processes can be initiated.
- Uncontrollable non-linear time behaviour of absorption
- Risk of negative influence of seawater chemistry after the application of new absorber
- Risk of negative influence of seawater biological environment at the end of absorber life time
- Absorption capacity can never be utilized on 100%