plumbing drain and return questions.

[smokinreefer]

hey all,
finally getting around to setting up my 65G.

couple questions, looking for opinions on what size pvc to use.

the tank is reef ready, so the drain is predrilled with 2 holes in the overflow.

the larger of the 2 will be the main drain, 3/4" with a gate valve. second will be used for emergency drain.

I plan to have a manifold set up with 3 or 4 returns coming off my return pump. am I correct in thinking that if I use 1" piping the flow will be wider? as opposed to going with 3/4" where the output would have less spread and have more velocity?

or will the drain not be able to handle the volume of water from 3-4 returns?

return pump is a jebao dc12000. (overkill I know, but its adjustable, and at the price point it was worth it for future proofing)

[WarDog]

I am surprised your main drain isn't 1 inch. Is it an aqueon, marine land or custom tank?

[asylumdown]

The number of return lines doesn't matter, only the total water volume entering and exiting the tank. I think max GPH of a 3/4 pipe is around 300 or 400 if you're not running it as a full siphon. As a siphon it's much higher

[smokinreefer]

Originally Posted by WarDog

I am surprised your main drain isn't 1 inch. Is it an aqueon, marine land or custom tank?

I think it's aqueon... I took the sticker off already

Looks like the hole is 1 3/4" so I should be able to get a 1" bulkhead to fit.
Thanks for pointing that out.

Originally Posted by asylumdown

The number of return lines doesn't matter, only the total water volume entering and exiting the tank. I think max GPH of a 3/4 pipe is around 300 or 400 if you're not running it as a full siphon. As a siphon it's much higher

Indeed, I understand about the volume in & out.
What I meant to say was, if I was to have decent flow coming out of that many returns, then maybe the volume would be too much for the drain to handle?

How would I go about running it at full siphon?

[asylumdown]

Sweet god I just looked up your pump. That's enormous overkill for your tank. The low end of its listed flow range is higher than 3/4" plumbing can handle, so unless you can dial it way back below that, you're going to have problems. It will overdrive your standpipe until it becomes a full siphon, then it will rapidly and suddenly drain until the siphon breaks. Over and over, it will sound like a toilet is flushing in your aquarium every few seconds. Depending on how high you set your emergency standpipe, it runs the risk of triggering that every time as well.

A full siphon on a 3/4" line can handle something like 2000gph (don't take my word for it, there's places online where you can look this stuff up for sure, I'm just going by memory). A bean animal style overflow creates a full siphon, but you need three holes for one.

Look in to Herbies, they're like a modified full siphon and you only need two holes. I'm still not sure if you can make that work with that pump though.

It would be much easier for you if you just replaced that pump with one that's more appropriate for your system. Do you really want to be blasting over 1000-2000GPH of water through your sump?

[WarDog]

IMO you should do a 1" drain with a 1" gate valve (as low as possible) and a 3/4" emergency a la Herbie. If you want to use that large of a return pump you will need to dial it back for sure and perhaps even add a valve on your return line. Also you could tee off after the pump and run a manifold system to feed reactors, chiller, UV, etc, and even have a line feeding back into the sump to relieve some pressure on the pump. The more restriction you have on water leaving the pump will significantly shorten its life.

[MinPhase]

Originally Posted by smokinreefer

the larger of the 2 will be the main drain, 3/4" with a gate valve. second will be used for emergency drain.

I wouldn't put a gate valve on the overflow simply because the flow is only controlled by the rate of return, if you restricted outflow from the display using a gate valve your tank would simply overflow. The only time you restrict flow is on the output side of a pump.

[LoJack]

Originally Posted by MinPhase

I wouldn't put a gate valve on the overflow simply because the flow is only controlled by the rate of return, if you restricted outflow from the display using a gate valve your tank would simply overflow. The only time you restrict flow is on the output side of a pump.

With both the Herbie and the Bean you put a valve to induce a full siphon, with a secondary drain handling the overflow. Much Much Much quieter than a durso, and much safer

[The Guy]

Originally Posted by MinPhase

I wouldn't put a gate valve on the overflow simply because the flow is only controlled by the rate of return, if you restricted outflow from the display using a gate valve your tank would simply overflow. The only time you restrict flow is on the output side of a pump.

A gate valve on the flooded 1" overflow refers to a "Herbie" super quiet and safe system and is done all the time, the second 1" is an emergency overflow that is located just slightly above the set water height in the tank to prevent a flood from happening. The size if the 2 pipes from the DT overflow to sump depends on the flow you require, I just used 1" as an example.

[MinPhase]

Also look into a durso style standpipe to reduce noise.