I am planning out a internal c2c with external box for my 40b build. All glass will be 1/4".
I'm wondering what the optimal distance between the tank trim and the top of the overflow would be. (I was leaning toward 1/4").
As of now I was thinking of making the c2c 3" tall and 1 3/8" deep. Should I make it bigger?
I'd like to add a sheet of 1/8" black cast acrylic to the vertical part to hide plumbing. I would keep the top of the acrylic 1/8" from the top of the weir. Same for the part of the external that is attached to the tank.
Im going to drill 2 or 3 1" holes for the water to travel from the c2c to the external box. I was thinking 3 would be better since it spans 12". Any insight is appreciated.
Could I position these holes so they're just above the bottom horizontal glass of the c2c? At this point a drop would be about 2" to the bottom of the external box.
External box will be 12" long 5.75" tall. I'm going to build my stand extra deep so the plumbing can travel straight
Into the sump with no elbows (except for the street at the intake). There will be around a 52" head. According to the calculator on beans site a siphon would drain around 2500gph 1" from 52" head and a 3/4 at around 1400gph. I don't need what the 1" is capable of and have read that 3/4 open channel and emergency is pretty useless for noise reduction/safety.
Could I have a 3/4" siphon and 1" open channel/emergency?
I'm not concerned with having complete silence, my main concern is safety in the event of a drain being clogged.
Lastly. Does just the siphon empty 1" underwater or should I have all three? If I'm correct the siphon won't let out air bubbles but an open channel will if it's under water. Assuming the same for emergency because at that point I don't care about bubbles the clog would be more of a concern.
Apologize for so many questions but I've read this thread front to back and it's a lot to absorb.
Any advice is much appreciated, thanks for taking the time to respond to this thread!
-Mike
The top of the overflow determines the water level in the tank. Depending on your flow, it the water level will likely be 1/8~1/4" higher, but should never be appreciably higher. I would just put the glass at the bottom of the tank trim (where the trim is on the outside glass, not the inner rim.)
The height of the CTC doesn't matter much, assuming it clears any bulkheads you may have. You will have a hard time getting a piece of glass cut 1 3/8" x 36", you may want to consider using 2 pieces of glass for the bottom or using a single piece of glass and angling it.
You are correct that a 3/4" open channel is pretty useless. You can have a 3/4" siphon and 1" open channel. The only problem with a 3/4" siphon is that it's harder to clean and very easy for critters to clog.
Have all 3 empty under water. The open channel will be carrying water all the time and if you don't have it under water the splashing will cause a lot of noise, salt creep and potentially dampness that can cause other problems.
The holes between the overflow and your external box should ideally be centered on the water level. I'd shoot for about a 1" drop to avoid excess splashing for the reasons mentioned above. You also need to be at least 1 hole diameter from the closest adjacent glass edge when drilling your holes.
what will your external box be made out of and how are you attaching it? If it's glass, you need to make it wide enough to safely drill the holes as I just mentioned. If it's acrylic, you need to have some means of securing it to the back of the tank(silicone will not work)