Ok ASD, you are about to get yelled at:

You can't just get around to fixing the ph when it suits you in hydro....you MUST get control of it or your plants will die. It's that simple in hydro. It's as if trying to grow in soil and saying "well I have everything I need to grow except I'm kind of fuzzy on that water thing so I'll just gloss over that part and go with 2 out of 3. PH is ALL in hydro. If you can't achieve a stable ph between 5.6-6.2 AT THE MOST over a 24 hour period don't even bother for very long because it won't happen for you (or anyone else with that kind of ph probs)

If your water isn't working or won't stay stable then use RO or distilled water.
Dump the britta filter....speaking from experience.

If you dont have them already get good quality ph up and down. USE them as often as you need to! You will need to check your ph SEVERAL times a day until you have stablized it. A good quality ph pen is nice to have too, but not necessary as long as you can measure ph in some accurate way.

You are overnuting.....but with ph being that wacky they probably aren't uptaking the nutes anyway but I agree with Jack completely....300ppm/tops for younguns'.

So DONT be looking to be sleeping too much real soon!

Jack if you get a chance could you check out my thread on "rootbound" in this forum and give me you opinion? Thanks...