Return Plumbing help

[alexkharden]

I have a question about plumbing my return. The tank is getting put in tomorrow, and I've been searching all over, but I really cant find a definitive answer.

My tank has 3 overflow holes, all 3 bulkheads are 1.5". My return pump is a Waveline DC-6000, and has an outlet of 1" threaded. I'll be using a Herbie overflow setup.

So should I step my return line from the pump up to 1.5" as soon as possible after the pump? Or should the plumbing all be 1" and then step it up right at the bulkhead?

Thanks!

 

[jpsika08]

In my case I left all the pipes at 1.5", though, I think it would've been better to have 1" instead so not too loose to much pressure.

What's the Overall size of the system?

 

[alexkharden]

190g, 75g sump/fuge. 265 total.

 

[jpsika08]

Your return pump has 1600 GPH at 0' feet, probably you'll get 1,000 to 1,200 gph at the end of the pipe, that's about 4 - 4.5 times water turnover which is fine.

Here is a nice Head Loss caluclator, http://www.reefcentral.com/index.php/head-loss-calculator, they probably won't have your pump but look for a similar one. Maybe try inputting 1.5" and 1" pipes to see how much loss you get between each.

 

[alexkharden]

136gph lost, that doesn't seem like much really. So the head loss will primarily be governed by the 1" outflow from the pump? Stepping it up to 1.5" won't really have an impact overall, since the outflow is restricted to 1"? Or do I have that wrong?

 

[DaveK]

Every time you make a transition in pipe diameter you will loose some flow, however since your going from a smaller pipe to a larger one, the loss isn't enough to worry about.

Make the transition where it's convenient. In the future. you may want to plumb other things off the main return pump and it's a lot easier to work with 1" pipe. Also valves and such for 1 1/2" pipe can be a lot more expensive.

Above all be sure you test your system and make sure the pump will not back siphon during a power loss.

 

[Squatch XXL]

So the head loss will primarily be governed by the 1" outflow from the pump?

"Head loss" is dictated mostly by vertical distance AND piping restrictions from fittings. The higher the pump has to move water, the less effective it will be. Increasing the pipe size will reduce the speed of flow, and it may reduce the volume a bit more, because the pump will be pushing a greater volume of water vertically. It is easier to push less water the same distance. As davek pointed out, enlarging shouldn't make that big a difference.

Each fitting in the return line will create restrictions, and that will again reduce the flow. Some reefers use flexible tubing instead of fittings because it has a much longer sweep, versus a pvc fitting which makes hard bends. Flex tubing is much less restrictive for changes in direction. I did not use flex tubing, but I did not use any 90s (quarter bends) in my 3/4" return. I used 2x 45 degree fittings (eighth bends) instead to allow for better flow. However my return goes into a Tee fitting on the bullhead (the face of the bull, with 2 horns coming out the sides).

In any plumbing application that requires a code inspector, this will fail unless he/she is blind.... It is very restrictive AND in some applications can erode the fitting to the point it becomes a danger (steam and condensate especially). When I get around to redoing my terrible plumbing disaster, I plan on replacing the Tee with a "Waterway Wye". It is less restrictive, and more suited to water flow. If you do not plan on splitting the return into the tank, than by all means keep it at 1".

I have to agree with @DaveK on the 1" vs 1-1/2". The cost of fittings is not terribly much, but the cost of valves starts getting pricey. Depending on the number of fittings you use it can add up however. If I had 3 overflow lines to the sump, I would probally use a bean-animal overflow...but I do not know how it is configured in your situation. I had to refresh my memory on herbie overflows, but it looks like they use 2 lines.

Also, as dave said, be aware of back siphon. What this is specifically is that IF/WHEN your pump is turned off by you or power outage, the return line will begin to suck water from the tank, down through the pump and into the sump. It will suck water UNTIL it is able to suck air. For a simple backflow prevention, you can drill a small hole in the return right at the tank's water line (Inside of the tank). This way, the instant the power goes off, it sucks air directly into the return line, and breaks siphon. I have a 1/16" hole in each of my returns right at water level. I get a bit of back siphon, but it quickly stops. I don't get much flow out of the hole when the pump is running, as the hole is very small, and the return is much larger....Water will take the path of least resistance every time.

I hope I am not being too technical.

*Edited some of my wording, because I am hard to follow even when I read it.....Even after edit, it still is hard to follow. Plumbing is hard to explain at times.


*Edit number 2. After researching Herbie overflow, I realized that I have a modified version of it. Wow, thats a great feeling.

 

[alexkharden]

No, not too technical at all. I was having this same conversation elsewhere, and here's what I ended up going with. It's kind of the opposite of what you just said, lol.

There's a hose barb adapter that came with the pump, so I'm going to do that -> short length of hose -> hose barb adapter to 1 1/2" MPT (I couldn't find a hose bard x slip fitting on US Plastics) -> 1 1/2" FPT to slip -> short length of pipe - > Cepex e-qua true union ball valve - > short length of pipe to the bulkhead.

Now I really need to figure out how to do the return inside the overflow. I've looked at loc-line, but they're so expensive. I've tried googling return setups, but mostly get the under-tank portion. What does everyone else do? I thought about building some kind of spray bar type setup, but have no clue if that would even work to spread the flow around.

My big concern is having enough room. I probably have about 2' to play with from pump top to bulkhead, so when I say short pipe lengths I mean it.

I'm really not sure why they did all three bulkheads @ 1 1/2", but I'll make the best of it. I want the short length of flexible hose to help minimize transfer of vibration up the rigid pipe.

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[alexkharden]

Oh, I just missed part of your post, I do plan on splitting the return inside the overflow, so I guess it's a good thing I went 1 1/2" for most of the run.

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[Squatch XXL]

The outlet is 1 inch. I personally would go to 1.25 inch right off the pump. You will lose a little pressure but gain a little volume.

I am going to have to respectfully disagree with this notion. If the pump has a 1" threaded connection, that would be the basis for overall flow as it is directly from the pump. The only way to increase volume is to use a pump with larger gph. Upsizing from that point will not allow for more volume delivered to the tank. It would still deliver a GPH equal to or less than rated as the outlet on the pump is still unchanged. Increasing the size of the line will decrease the flow rate (pressure), but should still retain a similar GPH.

If you have a 1" threaded connection, I would stick with 1" throughout. If the pressure delivered to the tank is too much, you can upsize close to the outlet in the tank. This creates a pressure drop because the cross sectional square inches is much larger than the supply line. Splitting the return evenly and at the same size as the supply line will reduce the pressure by half (Less based on restrictions from the splitting fitting...but this is a hypothetical example). Output Pressure can be increased by downsizing AFTER the split should it be necessary (strength of water flowing into tank from the return). However, upsizing to a larger size should not decrease the overall GPH, but fittings are more expensive at larger sizes. Example: 1" supply line into a bull head tee. Each side of the tee can be bushed down to 3/4". This increases the output pressure from 1"

I too have pondered creating a square shaped spray bar. So long as it connects in a full circuit, it should deliver even pressure on each outlet. However, there are some rules of pressure and volume that would dictate decreasing the size of the pipe based on distance from a previous outlet. This is hard to explain, but as an example: If I had 1" copper to my bathroom, I would drop off a 1"x 3/4" x 3/4" tee to the sink. I wouldreduce the bullhead to 1/2" on that tee. Then I would use a 3/4 x 1/2 x1/2 tee for my commode, than finally a 1/2" quarter bend (90 degree fitting) for the shower. Each outlet then is only 1/2 inch. I wish I had a photo of this. I am not a great plumber, but this allows for volume and pressure to be equal in the event that all 3 items would be used simultaneously...This does not mean that the pressure will be the same as the pressure in the 1" supply line, but that the pressure in all 3 outlets should be equal. This is not a perfect example, but the principal applies to potable water, as well as in industrial applications.....but back to the spray bar idea....So long as you do not "over-size" and provide SOME restrictions you could use one size pipe. However if you have a large pressure drop from the first outlets, the second set and further in the loop will not have the same volume and pressure. It is a matter of balancing the outlets by downsizing. A 1" pipe provides a bit less than 4x the total cross sectional size of 1/2". Pi x R^2 is your friend in this instance.


I may just be over-complicating a simple thing. It is a fish tank after all, and it will deliver water to the DT.

 

[cracker]

I'm all about volume not pressure. Increasing the " vertical' output diameter is about less friction . Depending on the pump and just how high You want to push the water, A 1.25 pipe off a 1 inch pump will deliver more volume. Check out the head loss calculator like Jpsik suggests. There is a difference between the power curve and head loss of a given pump.
alex ! I think Your plan will work out just fine for You!

 

[Squatch XXL]

It is still restricted by the initial 1" output. I love ya @cracker, but I don't trust an online hobby calculator to consider all the variables in fluid dynamics, Bernoulli's principal, and Newton's law of motion. I see that my pump is listed and I ran a test versus it, but it does not seem to consider that my mag drive 5 has a 1/2" output. Professionally I have never upsized a pipe from a pump to increase flow. Our engineers use long sweep 90s (quarter bends) and/or a series of double 45s (eighth bends) to reduce restrictions. However, my experience deals with pumps as large as cars and hundreds to thousands of feet of 6"+ chrome-alloy and carbon steel pipe. I do hate plumbing, but love pipefitting...there is a professional difference. I basically do not do a lot of potable water or low pressure applications (These terms are fancy for installing commodes and drinking water lines) . My current project is working with 200 pound steam and condensate. I am personally responsible for over 10,000 feet of stainless and carbon steel at the current moment....and we are nearing the home stretch. I am off today from work because I painted myself into a corner while I am waiting for a pair of large heat exchangers. It is more simple for me to sit at home, than to stand around at the job. A bad day at home is ALWAYS better than a good day at work.

I will just non-professionally point out that I disagree with some of the info on that calculator. The big thing is that no matter what size line returns from the pump to the DT that it will work great.

 

[DaveK]

...
There's a hose barb adapter that came with the pump, so I'm going to do that -> short length of hose -> hose barb adapter to 1 1/2" MPT (I couldn't find a hose bard x slip fitting on US Plastics) -> 1 1/2" FPT to slip -> short length of pipe - > Cepex e-qua true union ball valve - > short length of pipe to the bulkhead. ...

If at all possible, don not ever use a hose barb and hose. You get quite a bit of restriction doing that. I have found that the best thing to use is a union or a true union ball valve.

Note also how many fittings you have using hose barbs. Yes, hose barbs are easy to use, and that's why they get supplied with the pump, but they really are not the best option.

 

[cracker]

It's all good Squatch, I used the calculator as an example only. I base My Op's on research and experience with differing pipe sizes. Nothing like what Your used to. Maybe sometime we can have a debate on the subject. I agree that the output is 1 inch and that restriction is there. but once the water has passed that restriction and is allowed more area to travel vertically. Just kick that thought around.
Alex, So what did You end up doing?

 

[alexkharden]

The quote from me davek's post above is what I ordered. He said not to use hose barb, but I've seen a lot of sump pics with it and read many times that it helps with vibration and quieting the pump. So now I'm not sure about that part.

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[cracker]

Dave's right about barb fittings. They really restrict the flow. Plumbing with rigid pvc, using sweeps or several 45 fittings instead of 90's is best for flow.However it has to be carefully measured and glued..Lot's of work. I'm not familiar with Your waveline 6000. Maybe it's plenty of pump to overlook the barbs and such. That's Your call. I would think when 1st setting up a tank, that using tubing and barbfitting until You refine the setup is a good idea. Remember You can or will most likely change/ improve it later on . I know I have! LOL Good luck and let us know what You end up doing.

 

[DaveK]

The quote from me davek's post above is what I ordered. He said not to use hose barb, but I've seen a lot of sump pics with it and read many times that it helps with vibration and quieting the pump. So now I'm not sure about that part.

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Yes, you do see a lot of hose barbs and clear PVC tubing use on reef systems. It will work, and it does install fast, but in my opinion it's not nearly as good of an installation as PVC pipe is. I tend to use mostly rigid pipe and fittings with some runs made up of flexible PVC pipe.

You are also using a DC pump with a controller. You will get almost 0 vibration from one of those. Now if you had an externally mounted pump then you might have an issue.

If you want to give yourself a bit of a margen for vibration just in case, you can get flexible PVC pipe, also known as spa flex. It is not as flexible as clear PVC tubing, but you can glue up like rigid pipe. A heavy duty cement should be used.

 

[alexkharden]

I've actually never heard of spa flex, I'll have to head to home depot to check it out, if they have it. And I gave zero thought to ac vs dc pumps. I think that would make a difference, now that I think about it. Personally, I didn't like the thought of the extra fittings. A 1 1/2" slip bushing with a 1" threaded center would be SO much easier. I'll have to do some more reading before I finalize my plump job. Thanks!

 

[ianthepoolguy]

Spa flex is pretty much a standard in the pool industry, it's cheap and a direct alternative to sch80 rigid pipe
Imo, short lengths of a foot or so, do nothing for vibration or sound deadening.


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[alexkharden]

I ended up going rigid all the way up, no hose barbs or spa flex. I went 1" from the pump for about 5" to a 1 1/2" T. That T went 1 1/2" to the bulkhead and 3/4" to the fuge. There's a 1 1/2" ball valve immediately after the T to control the water flow to the fuge. Inside the overflow it goes 1 1/2" to another T, then splits to two 3/4" lines that go into the tank.