I would suggest that you change the first chamber to fluidised Kaldnes K1, and the second chamber to Japanese matting.
If you have a vortex chamber before each filter then convert this to static Kaldnes K1.
See http://www.koicymru.co.uk/ponduk03a.htm for an example.
The Kalnes should be soaked in Potassium before use.
Both Kaldnes and Japanese matting take quite some time to mature so it would be a good idea to convert one filter this year and the other next year.
Posted on Jul 22, 2005, 6:51 AM from IP address 86.128.124.147