Substrate is the gravel, sand, rocks or whatever else you are using on the bottom of the tank to plant the plants in.
70-100 watts is a good range. New Lights?
Put your tank dimensions in there. Then determine what light level you want. If you go very high light you will almost for sure need CO2 injection. Anything under can work without it although the up side of high light might need CO2 depending on how the plants react and how much algae you get.
No salt added?
How much light do you have now? How many watts if you know? What type, flourewcent power compact flourescent, T12,10,8,5? Should all be on the bulb.
Java moss doesn't need much at all to grow. I can't get it to live regardless of what I do though but that is just one of my little quirks, one of those Murphy's Laws that is a fluke.
Also, what type of fertilizer?
The stuff you add, do you know exactly what it is? Eco Complete, laterite, fluorite, something else?
Sorry for all the quesitons but this will all help us help you.