Can anyone help me get my Power Grooves to start properly? the ballast is grounded and the tubes are in their sockets just fine. They only turn on dim and start rapidly flickering.

 Is the fixture itself grounded ?

It's not a fixture really, it is just a weatherproof ballast (Advance RC-2S102-FO) for VHO or PG lamps. It is grounded but the tubes and socket are mounted to wood with a metal reflector underneath them and they worked fine yesterday.

 Is the reflector grounded ?

No cause it is mounted on wood so I don't have long enough leads to reach it.

 That could be your problem then .

Grounded the metal reflectors. Still doing the same thing.

 I'm out of ideas .

What about copper/aluminum tape or wrapping a very thin bare wire around the tubes? I know those are used for mainly assisting F40s and other fluorescent lamps start in humid weather/enviroments, but maybe they can help here.

It's 85 degrees and dry as a bone in my room right now

I don't have any experience with HO/VHO, but with regular dual-lamp rapid-start both lamps glowing faintly is not a sign of improper grounding.  Without ground either both lamps will remain dark (perhaps with a faint glow visible at the ends), or one of two lamps will be dim and the other out.  As soon as a discharge is established across both lamps, the resistance drops substantially and the presence of ground is no longer relevant.

There are lots of problems that can result in both tubes glowing dim, the most common being a cathode emitter loss but that's highly unlikely considering these are brand new.  Lack of cathode heating could be the culprit, and at leas in the case of normal RS the affected end may exhibit a purplish glow from the filament, and it will begin to sputter if the issue is not promptly corrected.  Usually the culprit is a poor lead wire connection to the socket, but other lamp holder and ballast issues could be to blame.

Another fault that effectively prevents cathode heating would be a broken cathode, so it'd be good to test continuity of each.

If both lamps are the same brightness even after being swapped it's probably not vacuum loss, but it could be the start of vacuum loss in one of lamps.

In these situations it certainly helps to have extra tubes, sockets, ballasts in order to narrow down the possibilities.  I'd probably start by first checking the lead wire connections to the sockets and also continuity of each filament.  Those are both easy to do.

Cleaned the contacts and checked resistance. Everything looks fine inside the tube. I even shined a flashlight through the ends to see the electrodes and they're all intact.

So both lamps just glow dim and flicker, is that right?  Does it look like any of the lamp ends have begun to blacken?  Do you see any purplish blue glow from any of the ends?

No, just flickering in a seizure inducing way with glowing hot electrodes at both ends (though one end is fainter in glowing than the other much brighter electrode glow on the red and blue side.

I'm not familiar with RDC sockets, but I presume if they don't cut power you could probe across the contacts to check for cathode heating voltage.  With regular R.S. at least this is about 3.6V.  Obviously be careful if doing this especially on the red or blue side where the voltage to ground is quite high.  You had an H.O. ballast that you were using previously, right?  Are you able to hook the lamps back up to it?