Plumbing A 75G Tank

[JH919]

Hello Salty People,
A couple of questions here, if you don't mind. Is a single 1" bulk head sufficient for an internal overflow box? Does it require an upside down 90 degree elbow installed inside the overflow box? (for noise reduction purposes). Also, is a Sicce Syncra 3.0 sufficient for a return pump? (inside the cramped return chamber in an Eshopps R-100 sump). Thanks again for your time.

 

[lmforbis]

I'd look at the 4.0 if it will fit. The gph they advertise is at the same height as the pump. Because you need to pump the water up to the tank that flow rate will be much less than the 700+ they advertise. The "head pressure" is the weight of the water above the pump which reduces flow the higher you go. You will want to plumb in a gate valve into your return line so you can adjust the flow rate.
1, 1" overflow should be fine. If it were me I'd do two. I like backups just in case a big snail decides to wander down the overflow.
On my new build I have 3. Two regular overflows and one emergency overflow that sits a bit above the water level just in case something happens that causes the water level to rise.
I like to put lots of unions in my plumbing so it can be taken apart if necessary. I also like a ball valve on each overflow pipe and the return line. These aren't to adjust anything but rather so I can isolate the sump from the tank if I need to. The gate valve on the return is to adjust flow in which dictates flow out. Gate valves allow fine adjustments ball valves are hard to adjust and are better as a on off type valve. I do t know what your over flow will be like or how visible it will be. You can paint the back of the tank. I use Rustoleum flat black primer for mine. You can also purchase black PVC (also blue, purple, orange, red, etc) at Bulk reef supply which won't be as visible as the standard white.

 

[JH919]

I'd look at the 4.0 if it will fit. The gph they advertise is at the same height as the pump. Because you need to pump the water up to the tank that flow rate will be much less than the 700+ they advertise. The "head pressure" is the weight of the water above the pump which reduces flow the higher you go. You will want to plumb in a gate valve into your return line so you can adjust the flow rate.
1, 1" overflow should be fine. If it were me I'd do two. I like backups just in case a big snail decides to wander down the overflow.
On my new build I have 3. Two regular overflows and one emergency overflow that sits a bit above the water level just in case something happens that causes the water level to rise.
I like to put lots of unions in my plumbing so it can be taken apart if necessary. I also like a ball valve on each overflow pipe and the return line. These aren't to adjust anything but rather so I can isolate the sump from the tank if I need to. The gate valve on the return is to adjust flow in which dictates flow out. Gate valves allow fine adjustments ball valves are hard to adjust and are better as a on off type valve. I do t know what your over flow will be like or how visible it will be. You can paint the back of the tank. I use Rustoleum flat black primer for mine. You can also purchase black PVC (also blue, purple, orange, red, etc) at Bulk reef supply which won't be as visible as the standard white.

The 4.0 is a smidge too fat (about .8" too fat). The 3.0 that I have seems to be strong enough. I was thinking the 1" bulk head in the internal overflow wasn't allowing sufficient flow to the sump, plus it "gurgles" as it drains. In fact, I had to turn the pump down. By doing so it does seems like not a lot of flow is coming from the return line.

 

[lmforbis]

Gurgles are normal. Google the bean animal overflow. It is supposed to be silent.
Glad the 3.0 has enough flow. There are other ways to reduce noise as well I am not familiar with them.

 

[2quills]

1" open channel drains are only rated for about 600gph safe operation.

Siphon drains are much more quiet. But I wouldn't turn it into a full siphon without a back up drain.