Originally Posted by Bobbss
Jpsdad, thanks for the info. You're one of the few people I've heard say you can use bentonite to seal a pond that has water in it. I've had a few people tell me that it worked for them, but most on here say you have to till it in and compact it.

I've worked on hundreds of leaking pond projects over the past 6 years and there's a dozen or so cases where bentonite was applied to a hydrated/full pond in hopes to seal slow the leak - some of these projects cost into the five figures and unfortunately, for these guys, bentonite didn't improve the leak issue. This doesn't mean it won't work, just means it didn't work for them. I think half the project cost was due to freight costs per Snipe. Closest source for us in NE is WY or TX - we've bid a few jobs and freight was cost prohibitive and blew out the budget. If I lived closer to a source and it was cost effective heck I'd try anything to get a seal.

I am typically the last gasp call made before folks are about to abandon their sealing efforts altogether. I try to talk them off the ledge and in some cases we try a polymer, in some cases I try to convince them to live with the seepage, or [last resort] fill in the pond. Whatever lines up with the person's goals and budget is the solution I recommend - I'm just here as a volunteer to try and help whomever I possibly can with pond related issues.

Regarding Bentonite application - I have always deferred to Mike Otto/Michael Gray direction which states it must be tilled into the dry basin and compacted with 4-6" lift of high plasticity clay. I've worked with polymers to seal dry basins with great success in a similar manner, but have no personal experience using Bentonite as, again, it's not cost effective for us in the Midwest and the polymer is far more efficient and friendly on the budget. There may be other ways to apply bentonite, but I'm not familiar with either of these pond builders ever discussing it.

To make matters a bit more confusing, Kenny comes along in the last few years and relates his success using soda ash [sodium carbonate] as a sealant. I'd never heard about this process before - and he's definitely the resident expert on the subject. I have no ideas on application process, application amount, or cost - but I always defer to guys who have directly worked with said materials on site and have practical, personal experience with the results. I would like to learn more so I can start providing it as a possible solution for leak issues, but I'll need to lean on Kenny until I understand it better.

These discussions are valuable as there may exist multiple strategies to help slow or seal leaks - and identifying the most cost effective method is everyone's goal. Good stuff.

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

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