Plumbing questions - difference in spacing of bulkheads between tank and sump

[JXNATC]

Here’s what I have going so far. I need 3/4” elbows for the return that I should get tomorrow. I mocked it up with a bigger pipe and I think it’ll work (using 45s). The emergency drain isn’t using the intended slot but this should work fine and doesn’t get in the way of my skimmer. I’m debating which way I want the gate valve knob to face. There will be about 12-14” open behind the tank due to a wall bump out. I find it pretty handy for storage lol.

current setup (we will repaint the wall while we swap the tanks)

Plumbing:

REALLY stupid question here, but how far should the pvc drop into the crash box? I have to think that the longer it is, the quieter it would be. I'm getting to plumb tomorrow, and I want to make sure that I'm as efficient as possible.

 

[hllb]

REALLY stupid question here, but how far should the pvc drop into the crash box? I have to think that the longer it is, the quieter it would be. I'm getting to plumb tomorrow, and I want to make sure that I'm as efficient as possible.

Mine drops into an overflow chamber so they just need to be below the level of overflow

 

[theMeat]

Use spa flex
Comes in all the standard sizes. Just use cleaner instead of primer before you cement it. Homecheapo usually has it too

The primary and secondary should end about an inch or so below water level in sump/crash box, whatever, for quiet operation. Leave them too long/below water level and purging air becomes more difficult, and noisy.
On the emergency drain leave it an inch or two above the water level so if it starts flowing you hear the splashing and know there’s a problem.

Oh,and I’m guessing you know the primary/full siphon line needs a valve and the other two drain do not, should not

 

[JXNATC]

Mine drops into an overflow chamber so they just need to be below the level of overflow

Thanks! Mine will be well below the overflow. The overflow is a bean. The primary and secondary lines will go into a crash box before the refugium. The emergency line is set to go into the skimmer section. I just wasn't sure if they should go a couple of inches from the bottom or higher up.