Mg Deficient?

[atropine]

Ok, this is my first post here, and this is my first try at hydro. Here are the basics that you guys ask for...

Plant Age: 3 Weeks
Strain: Unknown (Possibly White Rhino)
Hydro Or Soil: Hydroponic
Medium: Coconut Noir/Perlite
Type Of Light: 2 CFL
Atmosphere: Closet, w/Fan for air circulation
Waterings: Distilled, Aerated with an AirStone
Nutrients: Has just been flushed
Water Temperature: ~24.9C

Can anybody help me with this? I've been looking, and looking at pictures and posts about issues with growing, and while I think I've narrowed it down, I want to make sure I'm right before I go and try to fix it...
Everything was going great until about 3 days ago, when the leaf-tips started to shrivel a tad bit. Now, there are splotches of shiny green-brown on the leaves, and the edges are curling slightly. I think it may be Mg deficiency, as from what I have read, the leaves curl like this from it. Still, I'm not certain, and would appreciate any help. I flushed out the nutes yesterday, and have had it in distilled water since. Any ideas?

Here are the pictures:

http://i32.tinypic.com/24quzcw.jpg

http://i25.tinypic.com/iw20pv.jpg

http://i28.tinypic.com/2116u6f.jpg

[SmknVTEC]

Have they been fertilized yet?

[atropine]

Yes, I did have nutes, but I disposed of the solution, and now have the plant in distilled water, with a little bit of epsom salts. However, I didn't flush the perlite, as I did not want it all to float away while flushing it. Any ideas?

[SmknVTEC]

You don't need to flush. What's the pH?

[atropine]

The pH is right at 7.0

[SmknVTEC]

Way too high baby. Hydro and soil-less mixes at 5.2-5.8. Your plant is starting to lock out nutrients.

[atropine]

Wow! I can't believe I let that one slip by me there! Oh well, we all have our moments ... Anyways, thanks for the help, it was very much appreciated
So now, I essentially just acidify the solution till I'm at the proper pH?

[SmknVTEC]

Correct.