plumbing drain and return questions.
 

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)

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

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

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

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.

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?

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?

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.

I run a Speedwave 1320G - 24 volt DC speed controllable return pump and as mentioned dial it back to what you require or run it full out with a couple of T's after the pump to run reactors or what ever and or just dump extra flow back into the sump. This pump has worked great for me on my 90G reef with a 50G sump and was amazed with how quiet it runs compared to the Magdrive900 I had before. I would go with 1" for both your drains, herbie and your emergency overflow.
:rockon:

Everyone so far has made great points.

That pump is massive … I ran 3600 GPH through a Reeflo Dart on a 144 gallon tank with 50 gallon sump, and 1 1/2" drains (Bean) And I dialed that down by switching to the other impeller that is about 2600 GPH because it was just too much flow. I also have 4 outlets going into the tank from the return pump.

The more you dial it down, the more wear and tear on the pump, hence the shorter its lifespan.

With a manifold and an overdriven pump, you'll also need to remember that once you get your overflow set with your gate valves, any time you try to isolate one of the reactors, as an example … you'll have to close the valve, which will increase the flow into you're main tank throwing off your Herbie.

Just make sure that you aren't banking on head pressure, and relief through your manifold to make sure your overflow can handle the volume. plugged reactors etc could cause volume spikes into the display … and then you'll be in for a wet feet surprise which is every reefers worst nightmare.

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.

Also look into a durso style standpipe to reduce noise.