Partitioning & sealing a small indoor pond.

[wamil]

There's an inbuilt planter inside a hall that I intent to convert to a small pond, partly as a sort of trial run for a bigger project, to see what issues I might run into. (Also because I'm impatient and want to do something soon haha)

This container is 28"x53"x13" - roughly 83 gallons. I plan to partition a section for a small upflow bog.
I'm mainly wondering:

1. How should I construct the partitioning wall? I'm thinking natural or rough stone with mortar or something similar, but I'm concerned about if that will be ok for fish and plants, as well as if it will be watertight enough. (If the bog partitioning wall even needs to be watertight?).

2. How should I seal the walls and floor of the pond? It's metal and has already held rocks and plants for about 40 years so it's fairly sturdy, but the bottom just has a rubberized marine coating and the sides are standard wall paint (+ the wood rim) - I don't think this would be good for fish and plants.

3. What should I do for mechanical filtration? I'm thinking just a removable box with some reusable between the pump and the bog.

Recommendations for fish (or other critters) would also be appreciated, but I'm kinda leaving that choice for after it's built. I have nothing fancy in mind, just something hardy that would be happy in the small area, and tolerant of a first-time fishkeeper, and fertilize the plants.

 

[wamil]

I did some research, and I'm planning to use Pond Shield Epoxy over the existing walls and mortar with SikaLatex R for the bog partitioning wall. The bog side of the bog partitioning wall will also be sealed with the Pond Shield.

 

[wamil]

I ended up not using the SikaLatex; I figure it's not too big of a deal if some water leaks through since it'll just go into the pond anyway.
The sides have been coated with one coat of Pond Shield, and the wall is covered and curing now. I'll post my very poor masonry work after it cures. Any tips on countering the mortar's alkalinity? I plan to acid wash it, possibly apply some Pond Shield, and then monitor the pH until it stabilizes.

Would a pleco of some sort be a good fit for this? I think they're very neat, but I've never kept any fish before so I don't really know what to look for. I want to make sure whatever fish are in here will be happy.

 

[wamil]

Initial construction of the dam, the masonry is pretty poor but I've never done any before so it could've been worse I guess. The PVC is 3/4", with perforations drilled into the bottoms of the pipes.

First test: significant, both through the dam and the container.

Believe it or not, the main reason for the turbidity here is actually because that's how the water comes out from the hose. Well water has its quirks.

I added another layer of mortar onto the back, which helped but still didn't solved the leaks. I broke down and covered the whole thing with a few coats of that Pond Armor stuff, that's held up for almost 2 months now. I was worried the sheen of the epoxy on the rocks would look unnatural, but with water flowing over it, it fits right in.

Initially, I just filled it with about 3 cu ft of 3/8" pea gravel from Home Despot, but I had second thoughts. Also, that HD gravel was absolutely covered in dust. I rinsed it several times and there was still tons of dust.

Some changes were made, I connected the bog plumbing to form a loop and added a cleanout pipe + a snorkel for access to the bottom, the 'snorkel' is 4" perforated drainage pipe. I'm really happy with how it worked out. I also changed the first few layers to river rocks, then egg-size rocks, with about 5" of the gravel on top.

Beginning to look like a pond, what looks like a pipe-bomb is actually a DIY filter I made, filled with Poly-Fil to remove the seemingly-endless gravel dust. That actually worked really well, and also wastes much less water. I initially had a Danner 950 in here, but it was loud and developed a rattling noise like it had rocks in the volute, despite it being very clean. Good flow and very solidly built, but even with a new impeller the sound persisted. Maybe I just got a lemon.
In any case, I switched to a Jebao pump, and that has been working very well (so far) in addition to being nearly silent. The Danner has been relegated to backup/utility pump duty.

More indecision. After reading up on planted tanks and Walstad method, I decided to try some mineralized topsoil beneath a layer of coarse river sand.

To my surprise, I had zero issues with cloudiness here. I used some topsoil from my yard, with some added red clay as flocculant. My yard is in a flood zone right by the nearby river, I wonder if it being alluvial river soil in the first place helped in that regard. The cap for the soil is coarse river sand from the same area.

About a month later, after adding fish and plants:

Still a work in progress, but I'm pretty happy with it so far for my first real foray into ponds and aquaculture. I suppose the real test is long term stability.

The pH is pretty high, at about 8.2, but I think this is just as likely to be from my tap water (reaches 8.2 by itself after being left out for days) as it is from any concrete or rock leaching. On the bright side, it is a very stable 8.2.

 

[JRS]

Very interesting. I always thought something like that would be cool, as opposed to all my glass boxes. Thanks for sharing the process.

 

[addy1]

Very nice!