Cement ponds are usually just filled and emptied several times or scrubbed with a weak acid solution which is supposed to neutralize the free lime after which pH isn't supposed to be much of a problem. I wonder about very low level leaching though. You can of course seal them. I've seen designs for all cement tanks with glass fronts. This interested me because I could see forming planting pockets in the walls, a stone like finish covered with fern, no back corners at all, etc. The idea of alot of space, front to back, with the back sort of sloping away into the distance with no obvious corners seems to have alot of potential. The designs I've seen are old, pre-silicon sealer days (and basically just had flat backs). Has anyone tried such a tank using silicon sealer to hold in the glass? Or used another method? > > Date: Thu, 22 May 2003 06:07:46 -0700 (PDT) > From: "S. Hieber" <shieber@yahoo.com> > Subject: Re: [AGA Member] Lime It -- What's in it. > > I always wondered if, in that application, you would > get > continual leaching of the alkaline materials into > the > water. I don't guess that it's a problem but I > suppose if > it was an issue, you could seal the concrete. > > For backgrounds you might wnat to use what's called > "plastic cement", which isn't made of vinyl but is > portland > cement with an added resin that lends terrific > plasticity > to the wet mixture and increased resistance to water > penetration.. > > If the water is acidic, it will slowly eat away the > concrete, but that will take years and years and > years and > years, unless you keep very acidic water. You can > see the > slightly acid rain do the ame thing to sidewalks in > the > northeast USA, but you have to watch for a long time > ;-) > > - --- Dave Mosley <dxm1@cwnet.com> wrote: > > S. Hieber wrote: > > > > > > [snip] > > > > > > > I think that's neat. Relevance? Uh, you can > use > > portland > > > cement to make a pond base. > > > > Also to make nice 3D aquarium backgrounds... __________________________________ Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. http://search.yahoo.com ------------------ To unsubscribe from this list, please send mail to majordomo@thekrib.com with "Unsubscribe aga-member" in the body of the message. Archives of this list can be found at http://lists.thekrib.com/aga-member/