[Sir_BlackhOle]

First thing to do is focus on lighting and substrate....I usually recommend 2 watts per gallon at first. What type of lights do you have on the tank now? Are they incadescent or flourescent? How many watts?

Plain sand is not a very good substrate....you might want to think about adding some laterite or going with a comercial substrate like Flourite. Once you get these things you can start focusing on fertilizing.

 

[Sir_BlackhOle]

The cheapest method IME is normal output flourescents...2 watts per gallon or so. Doesnt really matter what spectrum....I like the daylight 6700k bulbs and they are dirt cheap. Laterite is a substrate additive and is pretty cheap. You just mix it in the bottom layer and then cap with more substrate of choice. Do a google search you'll find all the info you need. Poor mans fertilizers are KNO3 (Greenlight Stump Remover and can be found at any nursery,) Fleet type Enemas, and Seachem Flourish.

With 2 watts per gallon and no co2, you might be able to get by with fish food and Flourish Excell as your only fertilizers.