Most hydro growers use a 3 part fertilizer so that they can alter the ratio of each part to the others. The most popular 3 part fertilizers are made from General Hydroponics (GH) or by Advance Nutrients (AN). The 3 parts consist of (1) Micro (2) Grow and (3) Bloom. When adding these mixtures to your reservoir make sure you add them in the proper order. Micro FIRST!...then Grow...then Bloom. There are a variety of other supliments you can also add, but I suggest you start with the 3 part fertilizers first and go from there. Try not to make this more complicated than it needs to be. You could potentially open up more problems by mixing incompatable fertilizers together.

The ratio of mixtures are a matter of opinion and experience with certain strains of plants. It's up to you to determine what your specific plants need. Read more on this site about the "Lucas Formula" and you'll see many opinions of what amounts of each fertilizer to use. Again, it's up to you to determine what YOUR plants need. You should have a TDS pen/meter that can read the total disolved solids in your reservoir so that you can maintain the proper nutrient levels.

Here is a link to a formula calculator for Advance Nutrients. It also lists other supliments and the ratios for each.

http://www.mondoproshop.com/nutrient...cednutrients=1

If you're using reverse osmosis or distilled water, get some "Cal-Mag Plus" to replace the calcium/magnesium that's been filtered from the water.

Final note: If your plants are still in their infancy, use the nutrients at 1/4 strength or you risk burning your plants.