What a find! I'm not sure that you really need to do much with the rough edges once it is turned because you are going to bury it partially. First thing I'd do is test it to make sure it is holding water. Then you will know how to proceed and what if any spot needs reinforcement. I wouldn't worry about the rough edges as you could use the earth you dug out of the hole to mound up to the edge to cover the underside. Random flagstone or large river rocks could be used to cover the edge or just plants will grow over it quickly. I would landscape with plants and mulch to cover the mound. Any idea of the age of this tub? I would still be tempted to invest in a EPDM 45 ml pond liner which will last for years/decades. it will cover any holes or weak spots that might show up. If you are still worried about rough spots around the lip, carpet scraps will protect the liner. If finances are an issue, well washed roofing liner can be used. This pond will be a lot of work and you want your effort to last. If you have the $$$ to put in a proper waterfall, I would look into an external pump and filter. If you keep the rim on tub, be on the lookout for plant basket holders that fit over railings. The size looks about the same. I have seen them used to put in the water to provide the right height for marginal plants. Probably the biggest bargain here is the tub form but don't get discouraged. You have the start of something really unique. It will take some creativity and work. It will not be a weekend project. My first puddle twenty years ago was a twenty dollar garage sale find. Form, pump and spitter included! The retaining wall to build it above ground ten times that! That year my ten cent feeder gold fish got treated to a two hundred dollar rubbermaid stock tank for their winter home! I've since invested over ten thousand into this hobby but the enjoyment is priceless. Please let us see your pond development as this project progresses.

I'm trying to diagnose a leak from a fiberglass tub area. It's proving challenging because there are multiple spots under the tub that appear wet, yet when you see the inside of the tub, there is no apparent damage. Particularly I see water stains on the outside of the tub about 20 cm below where the tub spout is. The tub spout was not finished flush with the fiberglass, and the caulking has failed. I re-caulked it today. But the drip marks were not immediately around the hole for the spout. The white water stains have drip marks to the ground and the floor under the tub is soaked. But I also notice water actively getting through the tub where the tracking is for the shower door. Just in the one end of the outside of the tub which I have exposed, I saw 2 more wet spots. Does fiberglass sometimes get multiple pinhole leaks and cracks which are hard to see?

Looks like the width is 33 3/4" in the linked for the Memoirs linked one and it holds 52 gallons vs. the other only holding 38 gallons. I would do it now. It is likely something will need to be changed/fixed/updated when trying to install this one. You will need to rip out the tub surround to make it look decent for sure since the Memoirs is taller, not sure the drain is in the same location so that would need to be fixed too. Then the flooring will need to be fixed where it meets the tub. The Memoirs is not straight across like the original. So some needs to be cut and some may need to be patched due to the flare of the Memoirs tub. Unless you plan on doing this all yourself then it will likely cost about the same to have it fixed. If you are planning on doing it yourself then consider your time it will take to do the work as that is time you can't spend doing something else so also worth some money. If you do decide to renovate later then make sure the faucet gets installed higher on the wall to accommodate the new height of the tub so it is one less thing you have to move.

I guess I had just been looking at Lowe's and HD to see that a porcelain tub is $255 and acrylic is $250. I figured that was pretty darn cheap and don't see a reason to not go that route. I'll have to look into cast vs regular steel to see what the price difference is. If it's big I'm not sure that I'm willing to spend a big chunk but I'll have to discuss it with my wife.