This is a discussion on Ugh.....maybe sand was NOTa good idea after all!! within the Beginner Freshwater Aquarium forums, part of the Freshwater Fish and Aquariums category; -->
Now, I really don't know a lot about sand, I down have any, and when I do get it for what will be my ...
Now, I really don't know a lot about sand, I down have any, and when I do get it for what will be my small 60ltr barbs tank it will be play sand.
But what I THINK I know is you have to be VERY careful when using what is essentially salt water sand in I freshwater set up. As far as I know, and I Think it depends upon your tanks PH, this sand can break down quite easily and release a lot of calcium and alkaline matter into your tank. You really need someone with more experience to weigh in on that one though.
If it was me I'd do a little research on using it and if it's what I thought etc, just go and get playsand. It's less fine and so less likely to be a cloudy mess in there, and it won't set you back much as ite cheap as chips.
You don't mention the fish in the tank, nor the initial GH and pH of the source water (tap presumably). But the pleco and I saw a gourami, will not appreciate hardening water over time.
Aragonite is a calcareous sand that will release calcium and magnesium into the water slowly and continually for months and even years. This will raise the GH and pH. This is not going to be good for the fish.
I would strongly recommend replacing the substrate with inert sand (like the play sand someone mentioned, I use this), or a fine gravel.
I have a pleco and he is in my 90g which has a fine gravel substrate; when I changed the gravel to sand in the 115g tank I deliberately moved the pleco into the 90g, assuming from his normal burrowing that with sand it would be a continual mess. So consider fine gravel if this is annoying to you. But, as someone pointed out, sand is natural to the pleco, so it will not hurt it.