My Nitrates level is 50ppm+ (Tetra Test Kit) and I think my Phosphates are high too (waiting for my phosphate kit to arrive; backordered). This is because this tank has been setup for a long time (2-3 years).

I have had my plants for about 10 days and I see growth and new leaves forming. At this point I am only dosing Flourish and Flourish Potassium (Flourish Iron backordered). Since I have no algae issues, should I be actively trying to lower Nitrates/Phosphates or will they get consumed eventually. Of course I will be dosing Flourish Nitrogen and Phosphorus at that point.

Tank: 50g
Lights: 2x75w VHO
PH: 7.0
KH: 6.0
Nitrates: 50ppm
Phosphate: To be tested
CO2: DIY with a DIY reactor (Lowered my PH from 7.4 to 7.0)
Water Change: approx 40% per week.

If it ain't broke, don't fix it
Also if plant's and fishies seem fine, keep C02 up and the high levels will get reduced.
I would test the source water though just to find out what you need to dose when the time come's.

Thanks...I just wanted to make sure I was doing everythig right.....

Most people recommend a 10:1 ratio of Nitrates:Phosphates, but like the other person said, "if it ain't broke, don't fix it". Your nitrates look a tad high, if that's accurate, but it depends on how fast your plants are consuming them. Test your phosphates and then test them both again in a day or 2 to see if they go down. If they do, then add a little more. It's not an exact science, although some will swear that it is...you just need to find what works for your situation.