All I am using of substrate is silica blasting sand I found down at my local home depot. The front 2/3rds of the tank is just this sand. The back third is about 3 cups of Flora base substrate covered by plain coated aquarium gravel I picked up at the local petsmart. I tested the blasting sand for buffering by taking about 5ml of sand, and mixing it with about 2ml of dry Kent ph down (I think is carbonic acid). I then mixed it with water and watched for a reaction (bubbling, ect..) There was none. Therefore I am assuming the sand is inert. The other substate materials are either coated, or should cause a slight ph fall. Now if the plants are causeing the ph rise, then floating algea/java moss matts that cover a portion of the surface would be suspect. They account for most of the plant mass in the aquarium. At 10:56 AM 4/25/03 -0500, you wrote: Must be your substrate. What are you using? Now I want your substrate!!! Tomoko ----------------------------------------------------------------------- -- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. apisto-digest@listbox.com also available. Web archives at http://lists.thekrib.com/apisto Trading at http://blox.dropship.org/mailman/listinfo/apisto_trader