Is flagstone safe for aquarium decor and cave making?

[bekateen]

Hi All,
I was recently visiting a garden center/rockery store near me. I was looking for slate stone tiles I could use for decor and for making caves. The store had none, but they were selling something called Indian flagstone tiles, approximately 12" x 12" and about 1/3" - 1/2" thick.

Some of the flagstones clearly appeared to be sedimentary sand stone, which I would avoid like the plague because I would not it disintegrating in the tank and hardening the water.

However, other flagstones had more of a slate- or quartz-like appearance. I purchased a couple to experiment with it, but I'm not ready to add it to my tanks until I know more about it. I don't have a picture of it, but it resembles this:


Do you have any experience with this material? Can you give me any recommendations or warnings from personal experience or knowledge?

Thanks, Eric

[Narwhal72]

Yes. I use it all the time.

I drill holes in it, run stainless steel screws through and use it to weight down wood I collect from the woods.

I have also built a few caves with it but I found them too flimsy and easily broken compared to the terracotta ones and stopped using it for that.

I also lean large pieces up against the wall of the aquarium for cichlids to breed on.

Andy

[bekateen]

Thanks Andy. So you don't think I need to worry about disintegration and increased hardness of water or increased pH?

I bought 3 stones at $2USD each because the garden center was trying to clear them out. I'd like to break them up into smaller, irregular pieces and create stacked crevices, and possibly split some thinner to make caves. But I've never played with flagstone before to know how badly I'll do, and I don't have tile-cutting tools to be more careful.

Cheers, Eric

[Bas Pels]

With regard to hardening and pH - you could use a drop of stong acid. Put it on the stone, and it the stone reacts with bubbles, it contains CO3, most likely CaCO3.

Hydrochloric acid, 1 %, would suffice. I nevere tried other acids such as vinigar for cleaning purposes (10 % active ingredient, not suitable for consumption)

here, in Europe, the word flagstone was used for a reddish kind of soft stone, very well suited for tanks, but later all kinds of flat stones are put under that name. I´m quite certain some are suitable, others are not

[bekateen]

Here is one of the actual flagstones I bought. As I look at the surface, I'm concerned that the stone is flakey or laminated in form (that's natural for flagstones of course).

My new question is this: Do I need to worry that the edges of these flakey layers pose a significant injury risk to plecos spawning in the cave? I know slate can also have these edges and yet slate caves are very effective. If I attempt to chip away these flakes, I risk exposing new edges.

Does anyone with experience here have ideas about this? What do you think?

Thanks, Eric

[TwoTankAmin]

I have been using flagstone scraps for years. I pay next to nothing. My local stone and gravel yard sells flagstones for all sorts of landscaping projects. These are delivered by the truckload and stored standing on edge outside on wood slats. In the process of all this a variety of scraps break and shear off and are all over the place on the ground. The is the right half of an L236 breeding tank, those twoe males in the squashed caves spawned like mad. All those slatelike pieces are flagstone scraps


I go in with 1 bucket or two and wander around the flagstones and pick up the scraps whose size and shape suits my needs. They will charge me 5 dollars for a bucket load. I also buy a few of the river rounds- especially the red ones as they work great in tanks and provide red color.

[bekateen]

Thanks TTA.

I do buy all my river cobbled from this garden center. $15 for all I can fit in a canvas bag about the size of an oversized pillow case. And like you, I get to hand-pick my rocks by size, shape and color, the largest being up to 5"-6" across.

These flagstones were originally a special purchase by the garden center, but there was something wrong with the order so they are selling the intact 12"x12" stones for $2 each... A good deal. But I didn't think to ask about broken pieces. That's something for my next trip.

Cheers, Eric

[bekateen]

Okay, in preparation for cutting, I viewed several web pages and watched a few videos. I measured my stone tile, scribed it, and started the slow methodical hammering process with a tile splitter over a firm straight edge. Utter failure this time, as the stone fractured in the wrong places.

I imagined that I might mess up the first few times; that's why I bought three flagstones to start with. But more disconcerting is the horizontal delaminating that occurred, revealing sharp edges like broken glass.

What do I do about those? Nothing? And if it occurs so easily now, do I need to be concerned with future peels leading to cuts and injuries on fish tussling in passionate embrace when spawning in such a cave?

[MarcW]

Hi Eric,

That stone looks similar in appearance to the slate I use for caves/crevices in my tanks, although lighter in colour. When I'm selecting slate, I avoid any with the rusty streaks in it, as it may be iron deposits, I'm not sure if that would be the case with your stone though, we are several thousand miles apart, so the geology may be a little different .

To split into thinner sheets I use a bolster and hammer, I'm not sure if you would call it a bolster in the US, essentially its a heavy duty chisel used in construction for breaking house bricks in half, etc. To cut into sections for making caves I use a small angle grinder with a diamond tipped blade, its dusty and noisy (make sure you wear goggles and firmly hold/clamp the stone to something) but its effective and you get accurate cuts.

Regarding the sharp edges, I use a cheap file to rub off the sharp/flaky edges, it seems to work well and is quick to do.

[bekateen]

Thanks Marc.

[Narwhal72]

I never had any problem with the flakes harming the plecos.

I bought a cheap tile saw at Harbor Freight to cut my tiles.

Andy

[bekateen]

I bought a cheap tile saw at Harbor Freight to cut my tiles.

Ha! You don't know how many times I've heard people say that about Harbor Freight Tools' products. They should change their company motto to,

When you only need it to work once, and you can't borrow it from a friend.

[Narwhal72]

I totally agree with you. The tools are cheap junk.

But the tile saw only cost me $19.99. It's still running well too.

I would have to go through 5 of them before it would equal the cheapest one at Home Depot.

Andy

[bekateen]

Only $19.99? I just looked today online and their cheapest tile saw was $39.99 for a hand-held dry cut saw (not my desire) and $54.99 for a table top wet cut saw.

Dang... can I borrow yours?