Hi Curt
The biggest thing to remember when water gardening is that Hypertufa can be really bad at hold water and sealing it can be an exercise in frustration.
And as the peat rots over time it's ability to retain water becomes worse.
So a Hypertufa bowl that holds water now may not hold water next year.
If you are trying to keep the weight down you can use fine perlite or vermiculite instead of peat moss. Technically it will no longer be Hypertufa, it will be lightweight concrete.
There are several admixes that will help make your containers waterproof, AntiHydro has a great additive for this purpose.
But nothing seems to beat heavy old real concrete compacted, screeded, and trowelled for a great water proof surface.

Good luck, and have fun in the mud!

Glad to have you here! Your projects are terrific. I see fake rock making in your future.... along with leaf casting and sphere building and..... the sky is the limit.
I have a list of places where I have found neat leaf casting information and photos. If you want it just email me at ltd123@insightbb.com

Anyone who checks out Curt's site.... be sure to look at the video titled "mowing".

like the way you mow......lol

LOL !

It is cheating, but there are no kids about and it gives the folks next door something else to talk about !
Actually it does an excellent job and saves me an hour of following that thing about the yard by the time I move it a couple of times.

Where do I find Curt's site?

The site is www.gardenwaters.com
It is a brand new site that I am starting.

Here is a link that might be useful: Garden Waters

Don't know why, but that site seems to be very slow to load. I almost gave up on it. Same when I click on an internal link.

I am hoping they are just working on the server as I found it very slow loading myself.