The SYMBIOS HANDSET calculates no decompression times and decompression stops, depth and duration with a mathematical decompression model, which estimates the inert gas uptake and release during diving. The decompression model in the SYMBIOS HANDSET uses the Buelhmann ZH-L16C dataset. The model uses 16 hypothetical compartments for Nitrogen and 16 for Helium to estimate the inert gas loadings of the tissues of the body during a dive.
The popular gradient factor (GF) concept allows customization of the algorithm. The gradient factor concept allows reducing the maximum allowable compartment gas loading to a percentage of the maximum allowable loading according to the original Buehlmann ZH-L16 model. In other words, a gradient factor below 100, results in shorter no decompression times, longer decompression schedules and is more conservative than the original algorithm.
There are two gradient factors. Gradient Factor High (GF High) limits the maximum allowable compartment tissue on the surface. Gradient Factor Low is only relevant for decompression diving. It reduces the maximum allowable compartment gas loading at depth. A short GF Low setting results in deeper decompression stops.
The SYMBIOS HANDSET features a very precise pressure sensor, which can be also used as altimeter. This allows the SYMBIOS HANDSET to adapt automatically to the reduced atmospheric pressure in altitude diving.
A smaller GF High results in shorter No Decompression Limits.
Diving with a smaller GF High reduces risk of decompression sickness.
GF Low is only relevant when doing decompresion dives. A GF Low smaller than GF high results in deeper stops.
Do not change GF settings, unless you have the required knowledge about decompression theory, the m-value concept and gradient factors.