I been using Flourish Trace and Flourish Tabs by SeaChem. I am relatively new to the Fert scene so take my advice with a berg of salt. But it has been working well I think.
Tropica Mastergrow for the water.
Aquarium Pharm Root Tabs w/iron and Jobes Fern & Palm spikes for the gravel.
Fourish Excel for carbon usable by plants in the water.
Flourish Iron in water every other week esp with red or heavily planted tanks.
Liquids are best dosed daily in smaller amounts than weekly in larger doses. Gravel ferts should be added at least every 3 months.
What kind of fertilizer you use depends on the conditions in your tank so it's pretty individual as to the best thing to use. The Big Al's fertilizer works fine on most low light tanks and it's economical.
I pretty much use the whole Flourish line. I dose with Flourish every other day and after weekly water change I dose: potassium, nitrogen, Iron and fleet enema for phosphates.I also use florish root tabs every couple months. I know there is a much cheaper way of doing this but having a complete line delivered to my house works well for me.
OK, I keep seeing this FLEET ENEMA mentioned in the fert threads. Is this what I think it is? If it is I'm assuming that it can be bought at the local drug store, right? Also if it's what I think it is, does the drug store clerk look at you like 'What, another enema? Dude try some ruffage'