plants

i have just put a plant in my 90l fluval,but im unsure if there is enough gravel for it, could anyone advise on how thich the gravel should be and if i can add gravel to my established tank, thanks

A couple inches of gravel is fine, and you can add it to an established aquarium. Some people also put aquarium plants in clay flower pots. In any case, you may want to add some clay based substrate like Flourite or laterite to help the plants grow. The substrates can be very dusty, so you may have to change filter cartridges a couple of times. If you use a clay pot, you can put the clay based substrate on bottom and regular gravel on top. When I tried that I just made a big mess; you'll probably have better luck.

When I tried using dirt... I put it in the clay pot, and then put the gravel over it.

Then I poured water in the pot till it was well saturated... Even filled up with water. Before I put it in the aquarium.

This seemed to help from all the dirt floating up out of the pot.

I forgot about the hole in the bottom of the pot. By the time it got to the bottom of the aquarium, most of the substrate was on the fish room floor, and the rest of it was scattered all over the floor of the tank. Maybe the pot was too small, because it was impossible to get the root of the plant covered.

Most other aquarium managemenht tasks work out much better here.