Yes, the Cetus can be used on both gravity and pump fed systems. You simply swap the rubber boots around on the inlet/outlet

No, The Cetus Sieve I a mechanical filter only, it has no biological filtration.

The Cetus Sieve is suitable for use with both pressurised filters such as the K1 MicroBead, and non-pressurised filters such as the Nexus, the Cetus Sieve can be used with most brands of filter following the same installation procedure as outlined in the manual for the Nexus.

No, the Cetus will need to be gravity fed to install before a K1 MicroBead filter.

If the Cetus Sieve is installed on a gravity fed system it will need to be level with the surface of the pond (please refer to the manual). If the Cetus Sieve is installed on a pump-fed system it will need to be above the surface of the pond, if not it would overflow (please refer to the manual)

If the Cetus Sieve is installed on a system with a biological filter such as a Nexus, the balance pipe ensures that neither the Cetus or biological filter do not overflow.

If the Cetus Sieve is installed on a system with a biological filter such as a Nexus, you will need two pumps to install the Cetus Sieve as recommended, this ensure the optimal performance of both the Cetus and biological filter. If the Cetus is gravity fed you could use one pump but this would mean the biological filter would be raised above the pond. Only one pump is required if using with a pressurised biological filter such as a K1 MicroBead, the Cetus MUST be gravity fed.