Sponges have a greater capacity for absorbing menstrual flow than most tampons; though they should still be changed at least every eight hours. Sea sponges should be cultured at a salinity of 35ppt (salinity of seawater). Hypersalinity (high salt concentrations) in the immediate environment surrounding a sponge will dehydrate sponge cells, whereas a hyposaline (low salt concentration) environment dilutes the intracellular environment of the sponge. The pH of water must match that of seawater (pH 7.8–8.4) in order for sponge production to be maximized. Sponges are sensitive to temperature, and extreme fluctuations in ambient temperature can negatively affect the health of sea sponges. High temperatures lead to crashes in sponge cultures. Symbiotic bacteria that normally inhabit sea sponges start reproducing at an unsustainable rate when ambient temperature of the water increases by a few degrees. These bacteria then attack and destroy the sponge cells and tissue. It has been suggested that sponges should be cultured at water temperatures slightly below the ambient water temperature in the region the sponge has been originally isolated from. Photosynthetic endosymbionts inhabit many tropical sponges, and these require light to survive. Certain sponges as a result depend on light availability and intensity to achieve their nutritional needs. In some species however, light may lead to growth inhibition as they are sensitive to ultraviolet radiation. Other than when the sponge has associated photosynthetic bacteria, optimal sea sponge growth occurs in dark conditions. Dissolved oxygen is absorbed through the aquiferous system. Oxygen in sea sponges is consumed at rates which range from 0.2–0.25 µmol O2h−1/cm3 of sponge volume. Demosponges maintained under laboratory conditions can also tolerate hypoxic conditions, for brief periods, which could reflect their adaptability to dissolved oxygen. In closed culture systems some species of sponge may produce bioactive and cytotoxic metabolites which may rapidly build up and inhibit further sponge growth. However, biofilters are likely to be ineffective at removing secondary metabolites expelled from the sponge. Adsorption methods where biomolecules adhere to an adsorbate are likely to be an effective way of removing these compounds. Bath sponge disease outbreaks are often severe, having the potential to destroy both wild and aquacultured sponge populations. The underlying factors that result in disease outbreaks may be due to causative agents such as viruses, fungi, cyanobacteria and bacterial strains.