Fire-belly Newt Tank

Hi everyone,
This is my first post on this site, I hope that I am not posting a topic that has already been covered...

I have a couple of questions that I hope that you can answer for me.

Firstly, I am looking at making a tank for my 2 new fire-bellied newts, and I am not sure what I can use as a substrate. I was looking at different soil substrates (or possibly sand) that can be used, which can be covered by gravel.

Secondly, are there any suggestions of plants or moss that can be used inside the water and plants or mosses that can be used on the land section of my tank. I have seen Capillary Thread moss and Feather moss, but would they be bad for the newts?

Any other information on keeping these newts would be extremely beneficial since i have not been keeping them long.

Many thanks in advance!

Sand is usually the favoured option for these newts, or even bare-bottomed tanks (very safe and easy to clean). It is generally recommended that gravel isn't used, unless it's big enough to guarantee your newts will not be able to swallow them (and some newts have extraordinarily big mouths).

I can't advise on live plants because I use artificial ones, so I will leave that subject to another forum member

Even if the gravel is too large to be swallowed, it still makes a rather poor substrate. It traps a lot of debris and difficultates feeding and cleaning.
Fine sand is a far better option, but bare-bottom is the most practical.
There are plenty of plants that will work very well, like Elodea, java moss, java fern, various Hydrocotyle, Vallisneria, Anubias, etc, etc. You can find plenty more suggestions in the "Plants for Enclosures and Vivariums" section of the forum.
I do not recommend any terrestrial plants because there is no point in having a terrestrial area for this species. If housed properly, these newts will remain completely aquatic their entire lifes, perhaps only going on land for short periods to rest or avoid annoying males. At most, you just need a piece of floating cork bark for them to use if they happen to choose to. Anything more complicated than that is basically a waste of effort and space.

You can use Java mos, Christmas mos, Elodea, Cabomba aquatica, Pistia stratiotes and some species of Hydrocotyle. We find most eggs in the Java mos, so I can recommend it. Go for plants that are suitable for cold water. We've got gravel in the corners of our bare bottom tank and we've got a pump, but we've reduced the water flow to a minimum. H. orientalis doesn't like a current.

This has been the BIGGEST help in the world!! I will be adding sand tonight! I was reading other threads, and some people say that there aren't really any plants that are bad for the newts.. Can anyone else confirm this?

I can´t think of any plants that would be "bad" for newts, but you have to consider the requirements of the newts year-round to choose plants that will work well. As Niels said, look for plants that tolerate cold temps, and i would also suggest that they require low levels of light, no fertilizers or CO2, and ideally mix species that grow fast with things like java moss and java fern that grow slowlier. Plants that will grow close to the surface creating "rafts" of vegetation are highly recommendable.
Do not be afraid of using huge amounts of plants. The more you have, the better. A tank that is almost entirely full of green requires very little maintenance indeed, plus it makes an ideal home for this species.

One note about sand. Actually, two xD Rinse it VERY thoroughly before putting it in the tank. You will still get a certain amount of cloudinness in the water but it will go away in a matter of hours.
Don´t use a layer deeper than an inch or so. It helps prevent the formation of anaerobic areas which can be a serious problem. A layer of an inch or thinner is unlikely to develop such areas.

Okay, so what would I be able to do to create a large hill in the corner of my tank, which would not kick the nitrogen cycle out of sync?

You really don´t need it. If they are healthy and properly cared for they won´t use it at all, or at most for short spells at night. A piece of cork bark is more than enough for these guys.
If you are set on making something more complicated than a piece of bark, there are some lovely suggestions in the vivaria & enclosures section, that don´t take up too much volume of the tank. After all you want to take advantage of the available volume for water as much as possible.