Return plumbing question

[stilgore]

I will be starting the plumbing on my 300 this weekend (hopefully) as this is the first time I have undertaken such a large plumbing job I have a few questions.

Here is the first:

I want to maximized the flow through the tank. It is 8 feet long and I want to ensure I do not have any dead spots. Would I be ok if I plumbed two outputs under the water?

If I decided to do this I would either put a T in the return and drill the overflow or I would bring the PVC up over the overflow.

I ask if it would be ok because I have no clue about flow and the dynamics of water. I want to be sure there will be no damage to my pump if I have to shut the system off.

Thanks,
Stil

 

[Warnberg]

I would not plumb a return more then a inch or two under the surface, reason being is if the power goes out it will act as a syphon until the water gets to that level and air is introduced to break the syphon (believe me I know, though a check valve would work) and remember you are talking about 1 to 2 inches of water deep but 8 feet long by however wide your tank is (lots of water). If you want flow all over the tank it is best to use either power-heads or some folks plumb in a closed loop system.

 

[waucedah_joe]

A small hole, (or two for backup), drilled in the return line just below the water level in the display tank will break the siphon at that level when the pump is off.
By keeping the holes small not much flow is lost there and having the holes below the water line keeps them from spraying water all over. If you do that I don't see why you couldn't put the main discharge well below the water line.

 

[sam wise]

A small hole, (or two for backup), drilled in the return line just below the water level in the display tank will break the siphon at that level when the pump is off.
By keeping the holes small not much flow is lost there and having the holes below the water line keeps them from spraying water all over. If you do that I don't see why you couldn't put the main discharge well below the water line.

this is exactly what i have done on my 8ft. I ran the return pipework in 1.5" off of two oceanrunner 9500lph pumps. i have one return on each side of the tank (with the pvc looped over the top edge) the actual returns are 3" or so below water level but I have anti-syphon holes about 0.5" below the surface so when the pumps are off some water back-syphons into the sump, but there is plenty of capacity to avaoid a flood!! I also have a pair of general circulation pumps (one running a spray bar under the living rock and one blowing through the middle of the rock). my main returns from the sump are fitted with eductors which massively increase the flow (using venturi)

 

[rDr4g0n]

its been mentioned above, but one thing i have learned about plumbing is that it must breathe! ive started 3 floods with a new tank i added to my system because the plumbing couldnt breath. i added a tee that ensured that it could suck in air, and no floods!

another principle of plumbing is that the drain should always exceed the water supply. that means if you have a 1 inch pipe supplying water, your drain MUST be bigger than 1inch or you stand a chance of a flood. this principle must also be coupled with the breathing principle because even a larger drain wont be able to keep up with the flow if it cant breathe.

trust me man, trust me. *gets out mop*

 

[Devilboy]

I agree with RD.

If you want random flow. Your best bet is to plumb your return lines from the sump either up and over the back and attach locline. Or if you want to drill the tank for your return lines dont go more then a few inches below the water. Even if you drill siphon break holes, these holes are very small and can easily get clogged at the wrong time.

If you are going to keep a full out blown reef with SPS, let me suggest to you to plumb the returns up and over the tank. with your locline nozzles barely breaking the surface of the water, this will give you your surface agitation along with the overflows skimming the water. Then i would go a drill the tank, for a closed loop. You can place the intakes of the closed loop about 1/2 way down the back glass, then you can drill the closed loop returns anywhere you would like on the back glass. you could have em low, high in the middle it would not matter. You would have no flooding issues within a closed loop since the water will stay with in the closed loop systems plumbing.

I hope this helps

 

[boozeman]

or avoid the closed loop all together and just use tunzes and a multi controller

 

[stilgore]

Thanks for the quick responses. That spraybar under the liverock sounds pretty interesting. Anyone got any ideas on the best way to do that? Pics would be great!! My only worry would be that over time is would get clogged. Is that possible?

Thanks,
Stil

 

[Devilboy]

Thanks for the quick responses. That spraybar under the liverock sounds pretty interesting. Anyone got any ideas on the best way to do that? Pics would be great!! My only worry would be that over time is would get clogged. Is that possible?

Thanks,
Stil

I am sure spray bars may be able to get clogged. When i redo my tank, i will be putting a spraybar on mine and it will be part of my closed loop returns. the way i will be making mine will be so they are removable to be cleaned. I think i have a drawing of how im planning on doing it somewhere on the computer... i will try to find it.

 

[stilgore]

Fantastic!! I would love to see it

 

[Franksreef]

Make sure you keep the size of your return pump so that it is only turning the tank over 5x max. so in your case I would recommend a pump that will do 1500gph after head loss

 

[Devilboy]

It isnt the best drawing, but its what i have in my little brain.

If you have any questions just ask. As you can see in the upper right i put a list of items needed to make an adjustable spraybar. If you go this way, your parts may change or may not. Will depend on the size you will go with and what type of pump.

I will be using a ReeFlo Dart plumbed to a OM 4way. My 2 intakes will be with 1.5" PVC then joined into a 2" "T" then 2" PVC ran down to the dart intake which is also a 2" intake. My discharge side of the Dart is 1.5", so i will 1.5" PVC to the input of the OM 4way which also has a 1.5" input. Then from the OM 4way i have 4 outputs coming off the OM which 1".

Make sense?

 

[stilgore]

Thanks again for the info.

Franksreef said to keep the output of the return pump to around 5x the tank volume. I think the pump I have now is overkill. Why would I only want around 5x the tank volume?

Thanks
Stil

 

[Devilboy]

Thanks again for the info.

Franksreef said to keep the output of the return pump to around 5x the tank volume. I think the pump I have now is overkill. Why would I only want around 5x the tank volume?

Thanks
Stil

He is talkin about the tanks return pump from the sump. You dont want a pump to output more then what your overflow can handle. what pump u have?

 

[Jorgens]

Your sump/refigium is optimal (depending on size) at 5-10x your tank volume. I have about 5x in mine. It's a 180g main with 55g sump. And The flow there there is plenty.

Now what alot of reefers do on large tanks from what I've seen is a closed loop like what Devil drew. If your tank has a back then it's perfect. If your doing a double or 3 sides thing than it maybe more difficult. I personally did not have the guts to drill any holes below the water line. If you've got the guts, giver. The more I'm understanding about plumbing, the more I'm thinking about doing it. But I'm "see-thru" and still can't get the best angles.

I'd have to think the closed loop is your best shot for total water circulation. And you can get some massive pump job or even a good "hard-wired" pump that does 5k gallons an hour to get ya movin.

 

[stilgore]

Well, the pump I currently have I picked up from a lfs owner. It is a 2hp pump that he used for about 1 yr at his old shop.

I think it is rated at about 9k per hour at up to 75 feet. I really want to set up the plumbing to take advantage of all that water movement.

There is about 10 feet from the sump to the tank. I think there will be about a 5 foot rise through the tank and then I want to run one output around 6 feet over the tank to wher the wavy sea will be. Finally, I think I will make a run to my refugium and future frag tank.

My hope is that the pump will get the job done without being too little or too much.

Thanks as always,
Stil

 

[cracker]

I agree with boozeman, see if a Tunze sort of setup is in your budget before drilling. IMHO, an 8ft tank has SO many possibilities. Once you drill a bunch of holes in the back pane you greatly limit your options.

 

[stilgore]

The tank will be viewable on three sides with the overflow on one of the 24" sides. I will be a room divider. I wonder if I could place a run of pipe around the top edge of the tank and place outputs periodically? Maybe a total of 4 to 6 outputs?

Sorry this is dragging folks it is just that I have heard how important the flow is so I want to get it done right the first time.

Laters
Stil

 

[lcstorc]

That sounds like a manifold system. I keep saying I am going to set one up but I guess I am too lazy since it hasn't happened since. Here is a link someone gave me about setting one up.
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