Overflow Questions

[rebekwl]

I have seen of different opinions on this one.. Some say the GPH should be 5x the total water volume, some say 10x and i have even heard 20x? Would really like some input on this one. I will be drilling my 225 soon and we will have approx 300 gallons in total water volume. As usual, all opinions are welcome.

[madweazl]

If there are no holes, is it possible to setup an external overflow so you can run a beananimal return? Ideally, you'd use 1.5" hardlines giving you the freedom to run just about any flow rate you could want. If you're planning on running a refugium, they dont require a lot of flow. I have a Wavelince DC6000 on the second lowest power setting on my 75g (~20 in the sump for a total volume somewhere around 75g after displacement of rock, sand, etc.). Leave the high flow rates to the wavemaker/powerheads in your display. As for the magic number, there really isnt a right answer here. Any more flow in my sump and the macro algae would start to get ripped out of the sandbed.

[rebekwl]

Thanks for the response. I'm def considering the bean animal. Any thoughts on the Herbie set up? Also, with the bean animal, does the emergency have to be 1.5" also?

[madweazl]

For the beananimal you do want all drains to be the same dimensions. You'd want a herbie to be the same way but tanks often have pre-drilled holes that are different diameters so you use the smaller as the main and the larger for the emergency. The beananimal is the preferred system because of the redundancy and 1.5" opens up better options for plumbing (namely the sanitary tee). My 75g uses 3/4" PVC and it works well enough but you'd want much larger.

Edited June 27, 2016 by madweazl

[rebekwl]

Got it. Now the last question.. best place to get a BA overflow that will accommodate 1.5 bulkheads? Or just get one of the 16-1800 gph and drill my own holes? Most everything I'm seeing only come pre fabbed for 1"

[madweazl]

The setup I have came from ebay and the guy was willing to change sizes on the bulkheads at the time (imagine he still wood). I drilled my own holes and was really surprised with how easy it was to drill glass so I'd just go with the box and drill my own holes. For the size of tank you have, I'd think 1.5" would be a minimum.

Edited June 27, 2016 by madweazl

[rebekwl]

Cool I'll check eBay. Thanks again

[Rob A]

I think the reason those numbers vary so much (5x to 20x)  is that people forget that you can have flow inside the tank that is not related to the sump/return pump, and the higher numbers are needed for some corals.

 

You can have a sump with 5x turn over and then have a display with 20x flow rates using power heads. On my 220 I have a mag 18 return (so, approx 5x) and then a Gyre 150 as well as 2 MP-40's which, if all of them were running at full speed it would be 40x flow.

 

Some considerations for the sump flow rate...contact time for the skimmer and any macro algae. Bubbles from the skimmer need time to pop before they get sucked back into the return pump and pushed into the display, etc, so I wouldn't want too fast of a return.

[Anemone]

One way of thinking about the flow rate is that, if the goal is to keep consistent parameters between the display and refugium, then the flow rate is dictated by the size of which ever has the smaller volume. To take an extreme example, if the ocean was your tank, you wouldn't have to push 5 ocean volumes per hour through your fuge. It'd be sufficient to turn over the fuge volume a few times per hour. Let the ocean mix itself.

[rebekwl]

One way of thinking about the flow rate is that, if the goal is to keep consistent parameters between the display and refugium, then the flow rate is dictated by the size of which ever has the smaller volume. To take an extreme example, if the ocean was your tank, you wouldn't have to push 5 ocean volumes per hour through your fuge. It'd be sufficient to turn over the fuge volume a few times per hour. Let the ocean mix itself.

Just to be clear I will be running a fuge. We are Planning a 100-125 sump as well. So, should I be looking to turn over the sump 3-5x and leave the "Big" turnover rates to the powerheads in the DT?

 

I think the reason those numbers vary so much (5x to 20x)  is that people forget that you can have flow inside the tank that is not related to the sump/return pump, and the higher numbers are needed for some corals.

 

You can have a sump with 5x turn over and then have a display with 20x flow rates using power heads. On my 220 I have a mag 18 return (so, approx 5x) and then a Gyre 150 as well as 2 MP-40's which, if all of them were running at full speed it would be 40x flow.

 

Some considerations for the sump flow rate...contact time for the skimmer and any macro algae. Bubbles from the skimmer need time to pop before they get sucked back into the return pump and pushed into the display, etc, so I wouldn't want too fast of a return.

So If I'm Understanding you... Your Mag is capable of 5x turnover of your DT. However, you don't have that much going through the sump?

Edited June 28, 2016 by rebekwl

[madweazl]

There is no need for high flow in the refugium but there is a need for higher flow in the DT if you plan on having corals/anemonies. 5x total capacity through the refugium is more than likely just fine (~1500gph) but inside the DT that will not be moving much water. By comparison, an MP40 pushes somewhere around 4500gph and a tank that size would probably need at least three of them.

[Rob A]

So If I'm Understanding you... Your Mag is capable of 5x turnover of your DT. However, you don't have that much going through the sump?

 

The mag-18 is in the sump and at 5ft head moves about 1100gph (not counting the drop caused by elbows, etc) and that is all flowing through the sump. So the sump is seeing 1100gph or roughly 5x the volume of the display per hour. My total volume of tank and sump is around 270 if you don't subtract the displacement from rock and sand...so maybe I only have 220 to 240 gallons if you subtract the volume of sand and rock (just guessing). 

[rebekwl]

There is no need for high flow in the refugium but there is a need for higher flow in the DT if you plan on having corals/anemonies. 5x total capacity through the refugium is more than likely just fine (~1500gph) but inside the DT that will not be moving much water. By comparison, an MP40 pushes somewhere around 4500gph and a tank that size would probably need at least three of them.

Ok, I was mixed up About the quantity/turnover going through the sump. I was thinking that 5x the sump volume(500-600) was sufficent. But I need 5x the total volume (1500) going through the sump, and the higher rates(4500+) in The DT will be done by the powerheads.

[rebekwl]

The mag-18 is in the sump and at 5ft head moves about 1100gph (not counting the drop caused by elbows, etc) and that is all flowing through the sump. So the sump is seeing 1100gph or roughly 5x the volume of the display per hour. My total volume of tank and sump is around 270 if you don't subtract the displacement from rock and sand...so maybe I only have 220 to 240 gallons if you subtract the volume of sand and rock (just guessing). 

Got it. If you don't mind me asking, what size is your sump and what size bulkheads did you go with? 

[Rob A]

My sump is kinda dumb...I have a 29 gallon tank and a 40 gallon breeder connected by two 1-1/2 pipes. The display drains into the 29 gallon also with two 1-1/2 pipes, then that flows into the 40 gallon tank where the mag-18 sends it back up to the display. I have this 1500gph overflow kit from glass holes that uses two 1-1/2 bulkheads 

http://glass-holes.com/1500-gph-Overflow-Box-Complete-Kit-gh1500kit.htm

[rebekwl]

]My sump is kinda dumb...I have a 29 gallon tank and a 40 gallon breeder connected by two 1-1/2 pipes. The display drains into the 29 gallon also with two 1-1/2 pipes, then that flows into the 40 gallon tank where the mag-18 sends it back up to the display. I have this 1500gph overflow kit from glass holes that uses two 1-1/2 bulkheads 

http://glass-holes.com/1500-gph-Overflow-Box-Complete-Kit-gh1500kit.htm

That's actually a pretty cool setup, and at the end of the day it works? Then it's not dumb at all. My 92 corner is set up weird like that. I have a 15 gal That the DT drains into, Goes through 3 Chambers to the Mag 9. Where it tees (before going back to the DT) Going into an 11 Gal fuge, Then Gravity drains back to the return chamber.  So, Would you have done anything different? Am I shooting to high @ 100-125 Sump? or could I use 75-90 And be fine?        

Edited June 28, 2016 by rebekwl

[madweazl]

Ok, I was mixed up About the quantity/turnover going through the sump. I was thinking that 5x the sump volume(500-600) was sufficent. But I need 5x the total volume (1500) going through the sump, and the higher rates(4500+) in The DT will be done by the powerheads.

 

Your total volume will probably end up really close to your DT volume in the end because of the displacement of the rock, sand, and the relatively low water level in your sump. I think you'd mentioned that you were going to partition your own sump, something to keep in mind is the water level that works best for the skimmer you'll have (only the skimmer compartment needs to be this level; not necessarily every compartment). If the recommended level for your skimmer is really low, you can raise the skimmer using something as a shim (eggcrate, pieces of acrylic, etc.) so the water level in the sump doesn't have to be that low.

Edited June 28, 2016 by madweazl

[Rob A]

I would have used a 75 gallon on mine except that it would have been too tall for inside my stand and would have made it hard to get into for skimmer maintenance, etc. I also considered a 55 but after calculating the operating height of the water the amount of space left over for overflow during a power outage wasn't enough...so I came up with this other plan.

As far as which one you should use it depends on a few things. A few things I would consider:

-overall water volume-do you want/need more to increase stability? If you already have a 95DT then it might not matter much   

-overflow levels during a pump failure or power outage

-room for equipment, skimmers, reactors, macro algae, etc

-room in the cabinet-maybe you don't mind filling it up completely with a sump or maybe you need room for power strips, power bars, etc

-thickness of the glass if you are or if you want to run an external pump. I just bought a used 300 gal that came with a 125 gal sump and external pump. The glass on the 125 is a lot thicker than a 40 or 55 so I am not worried about the stress on the glass of the bulkhead being connected to a pump.

Edited June 28, 2016 by Rob A