So sounds like their strategy is to provide us with a very nutritious substrate that runs out after a year or two and if we adhere to the lean water column doctrine then it is then that we need to buy some more substrate... So not only that this substrate is very expensive but also we spend all of those $$$ for something that runs out after 2 years? Aviel. -----Original Message----- From: aga-member-bounces@thekrib.com [mailto:aga-member-bounces@thekrib.com] On Behalf Of Tomoko Schum Sent: Tuesday, July 12, 2005 8:52 PM To: Aquatic Gardeners Association Member Chat Subject: Re: [AGA-Member] Possibilities of Sozo Haishoku >> But one thing that he said is "news" for me - He said that there's a time limit for an aquarium and at some point one has to replace the substrate and "renew" the tank. I thought that a reasonable substrate runs out of nutrients (except iron) in about a year or so however it should still absorb some nutrients from the water and my impression was that water column is the king as far as fertilization so no need to care so much about substrate anyway.<< When it comes to fertilization, ADA's method is quite different from the popular approach among AGA members. You might have noticed from the data sections in their articles that ADA keeps the water column very lean. Tomoko _______________________________________________ AGA-Member mailing list AGA-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/aga-member _______________________________________________ AGA-Member mailing list AGA-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/aga-member