Few things I did/figured out this morning.
The gurgling drain, it had to be fixed. The air hole in the top was the culprit, as when I plugged it with my finger I could tell the bubbles in the sock stopped. I placed a piece of black electric tape on it and adjusted my gate valve to regulate the full syphon I just made.
Now, I have no bubbles being made from the overflow. Only problem now, is when I turn the return off and back on it takes too long to return to full siphon and the return runs dry, churning up a TON of air.
So I decide I'm going to drill air hole in the elbow for the drain. It will be under water when running, and allow trapped air to escape on starting the pump.
Bingo, that problem is fixed. No more air being pulled into the drain, and it starts quickly and obtains full siphon. No more bubbles getting into the refugium section. It gets water from the left of the filter sock, straight from the return.
The skimmer section gets water from the filter sock, and didn't get any of the bubbles. I did find that it is making bubbles tho. Not the skimmer, it's off for now until I get eveything fixed. The overflow from the skimmer section into the return section is causing large bubbles to form. My return pump is cavitating and turning these large bubbles into micro bubbles.... here's a video explaining what is happening.
Not kidding. Few different steel targets.
