I've never heard of people putting sheetrock in their ponds but sheetrock/plaster has a lot of gypsum in it which I'm guessing is where that idea came from. There's a place in So. California desert called Plaster City because it is a hub for the gypsum mines in the area. I've heard that the gypsum mined here is primarily used for plaster and sheetrock.
To all,
I have a question regarding the use of gypsum and alum: Are these treatments long term solutions or do they need to keep being applied? My specific concern is in irrigation reservoirs where the water retention time can be much shorter than most backyard ponds. It could get expensive to have to keep applying every time there is a water change. Also, would there be any reason to be concerned about Alum effect on plant physiology? I assume it would precipitate out with the clay and not get sucked in the intake. Can anyone comment on this?
Richard Dennis EP Aeration rich@epaeration.com www.epaeration.com (800) 556-9251
