Why do we assume a large return pump is needed?

[sjm817]

Finally got around to lowering my sump flow volume today. My setup is a 90G AGA with dual HOB Amiracle overflows and a DIY 30G sump/fuge with a Mag9.5 return. I have a Remora Pro w/Mag5 in sump. I dual overflows work well for my setup and I didn't want to change it.. The way I made my sump/fuge setup, the dual drains work out well. I did this not too long ago and didn't want to re do the drain setup. This presents a small issue since I cant go too low in flow. I have to have enough to keep the U Tubes running free of bubble accumulation.

When i redid my sump/fuge/plumbing setup. I did as Danner/Mag recommends and replaced my 3/4" plumbing with 1.5". It got Y'd twice into (4) 3/4" returns. The increased tubing size did up the flow considerably from what it was. The thing is, I could never get it free of micro bubbles, and it seemed to accumulate crud in the tubing. I also had to run a filter sock to keep the micro bubbles mostly under control. After reading this thread, I decided to back down the flow through my sump.

I came up with a couple of options:
1) drop down to a Mag7 with small dia plumbing
2) keep the Mag9.5 and put in a SCWD. It is well known to cut down on flow. The wavemaking sounds like a good idea.

I decided to try option 2 first. I'm back to 3/4" plumbing out of the Mag9.5. Since the SCWD is flow restrictive with the 3/4" barb fittings and all, I didn't see much point in going with anything larger.

Hooked it all up and fired things up. I could tell immediately the flow was like 1/2 of what it used to be. Before, the overflow weirs were right up to the top, now they are sitting quite a bit farther down. I checked the U Tubes and I just barely have enough flow through them to push bubbles through, where before they fly right through. I may get smaller dia U tubes.

I removed the filter sock and what do you know. For the first time, I can run without one! :dance: I do have a bubble trap, but it wasn't enough before. Now it works perfectly! The alternating flow of the SCWD and the (2) MJ1200's are doing a great job moving water as well.

I'm thrilled with the improvement. Not sure yet how this will affect skimmer performance, but I am hopeful.

Thanks for originating this thread. It makes a lot of sense and has helped me put a great deal.

 

[Herbert T. Kornfeld]

glad it worked out.

 

[kimoyo]

The intakes should be as close to the surface as possible w/o every being exposed to air in case the sump turns off (and the tank's water level drops).

-Herbert T. Kornfeld

Herbert,
Some people will plump their CL thru the overflow (but not using the overflow water). And you stated that you like the CL inputs near the top. Will this interfere with the skimming on the surface? Wouldn't the CL input draw in the skim?

Also, where do you like to have your CL returns? Do you have your inputs at the top and returns at the bottom? Is there a problem with this? Thanks.

Paul

 

[bertcmg]

Finally someone said it.



I agreewith the original poster completely

As an example

I now run a Mag 5 as return on my 130 G tank

The mag5 returns through my chiller and empties into the tank

I am assuming that I am prolly getting max 2-3X tunover due to the fact that my tank stand is higher than most

I do however have a lot of in-tank circulation provided by 2 tunze Streams ( 6100's ) housed in the deco rocks to give a completely natural look to the tank.


As a added benefit I have found that my tanks evaporation rate has been reduced by half.

My eletric bills seem to be a lil better than when I was using two T4's for circulation

I find that waste settles in my sump much more now ( easy cleaning)

No more micro bubbles ( Don't have a big sump anymore )


Above all my PH swing is actually less now ( .3 in PH swing day-night)


Bert

 

[Ruu]

good thread, looks very interesting,

but what you guys think about how the low flow will affect things like carbon/phosban reactors, UV units, heaters, ect, will the low flow affect these in a good way too,

I just downgraded my return pump to an Eheim 1250. My temperature prior to that (Mag 7) was swinging about 2 degrees each day. The temperature of the main tank (according to the thermometer on my chiller, which measures the main tank since it is on a CL) has varied by exactly 0.1 degrees over the last 36 hours (I have been keeping strange hours and checking a lot). The heater is still kicking on regularly. Much of this can be attributed to the reduced heat coming from the Eheim (damn those Mags get hot), but as far as heaters go I see absolutely no disadvantage to going low flow through the sump - the temperature in my main tank is absolutely rock steady.

Dave

 

[Herbert T. Kornfeld]

kimoyo06,
the intakes should not be so close to the top that they are actually drawing air or water from the surface. Just a few inches below is fine. I didnt intend to make it sound like it was THAT close. As far as outlets, anywhere you like, and one of the big bonuses of a CL is that you can put a couple outlets close to the bottom to keep the sand clean, or even run pipes under the rocks, to the front glass, and then blasting the corals from the bottom front edge of the glass.

Thanks for giving your experience Ruu. The only two things I can think of that really would need more flow through the sump might be a refugium, mechanical filtration of particulate matter that might keep blowing around from circulation pumps and need to be collected somehow. However, these are both things that can be worked around. A mechanical filter on the closed loop, a sponge filter, a hob refugium, etc...are all ways around these 'glitches'. Heating a 125 with just 100gph through the sump is not a problem unless your tank is in a fridge. UV? Thats very 'stone-age-reef' along with wet-dry. Not that you would be trying to cycle your whole tank through the UV every few minutes anyways. Phosban & carbon reactors....low flow shouldnt hurt them...if you need to treat your water that bad then you have issues.

 

[kimoyo]

Thanks Herbert.
Paul

 

[joseney21]

i love the thread, thanks herbert for bringing the issue up.i'm getting a 180 soon and i'll be trying this technique from the start.i'll post pics and progress in the near future.

 

[Black71gp]

herbert...awesome thread. quick question for you. i am setting up a 190 i bought used. right now it only has one overflow box on the side, and has a 1 inch drain and 3/4 return, i was thining that if i went with just a 1.5 drain and 1 return that would be fine and i would not need to add another overflow. am I thikning right. i plan on have a return with two eductors and a closed loop with a larger high flow pump.

 

[spamin76]

I think it is just easier and cheaper to drive everything off one huge return pump than using powerheads, tunzes, etc - which require extra maintenance, extra things to buy, etc.

 

[tgreene]

I too am in the process of setting up a brand new 125 reef, and have purchased the larger of the Amiracle overflows (a dual that's rated @ 1600gph) for the task. I'm planning on using 1 leg of the overflow to run a CL, and it will be run with either a PanWorld 100-PX (790gph) or a Mag 9.5, while the 30g sump is driven by the other pump. I may even opt for a 2nd PW pump, since I like them so much.

I'm planning to foam the back wall (with a thin dyed cement coating) and have the CL returns embedded behind the foam and under the sand, to be in the front corners pointing up and back with 45* reducer fittings that act as nozzles. The idea is to hide absolutely everything that can be hidden, including the overflow, which will carefully be sculped into the foam so that it's hidden yet still removable for cleaning.

This is a 72" tank that is the center piece of my livingroom, so I plan to use every possible trick that I've learned over the years, to make it perfect.

To greatly reduce the possibility of power outages, I have purchased the new APC BR1500 battery backup system that gives me up to 110 minutes of runtime (based upon a computer and monitor), and will likely be adding the additional battery packs to it, giving me up to 360 minutes of runtime.

 

[Herbert T. Kornfeld]

Black71gp, that is not quite the idea here. For a 'low-flow' smart use of energy, you can leave your overflow as is...only running 200-600gph through it with the sump pump. No eductors on the outlets from the sump. Use a large closed loop or circulation pumps like you said, maybe even put eductors on the closed loop.

spamin76,
so for a 125 gallon you would need to use a sump return of what...3000gph? Thats going to suck up something like 250watts? A closed loop / circulation pumps & low flow sump return can be done for less than half that wattage. And, reliability? Well, circulation pumps in general are longer-lived because they arent dealing with the wear & tear associated with back-pressure. NTM, a 125 with 3000 gph going through it requires larger overflows and lots of noise from those overflows.

tgreene,
you cant run your closed loop intake off of the overflow box. It will run dry. Otherwise...why did you post that here? Nothing that you are talking about with your tank is like what we are talking about here.

 

[kimoyo]

I'm thinking about getting Eheim 1250(sump return) and Eheim 1260(chiller). Are they quite? How's the heat? Thanks.
Paul

 

[Black71gp]

alright i will leave it as it is, and the reason i was going to do eductors on the return pump is because it is a pressure rated pump already and the CL pump will probaly not be depending on what i get.

 

[Black71gp]

alright i will leave it as it is, and the reason i was going to do eductors on the return pump is because it is a pressure rated pump already and the CL pump will probaly not be depending on what i get.

 

[tgreene]

tgreene,
you cant run your closed loop intake off of the overflow box. It will run dry. Otherwise...why did you post that here? Nothing that you are talking about with your tank is like what we are talking about here.

Ummm, not according to YOUR own post!

By using different height and diameter drain pipes, I most certainly can accomplish this with a high volume overflow.

And I know the question always comes up...why not run the CL off the overflow? Well, you can...ONLY if you have a very large overflow box....and usually isnt worth it then. See, if the sump pump is turned off, you need enough water in the overflow box to maintain the closed loop. That means you need a standpipe and the sump overflow to be above the closed loop intake...otherwise the CL would run dry. Not only that, but the height between the two intakes (CL below, Overflow above) must be enough to maintain a water volume large enough to maintain the CL if the CL pump were to turn off and then on again while the sump was off (think about it while the sump is off, turn off CL if it feeds from the overflow that means that the level in the overflow will rise...going down the overflow drain to the sump...CL comes back on and doesnt have enough water to run). And then what about evaporation? The overflow box needs to function as your new sump pretty much...too much hassle for most to bother running the CL through the overflow.

 

[Herbert T. Kornfeld]

kimoyo06
I love my eheim pumps. I have a few of the 1250s...good all around pumps. Perhaps the best 300gphish pump you can buy. I had one running for almost 15years straight before the impeller finally broke. Never made a peep, never stopped. The wattage is pretty low as well so it doesnt put alot of heat in the water...even if you submerse it.

 

[bertcmg]

I think it is just easier and cheaper to drive everything off one huge return pump than using powerheads, tunzes, etc - which require extra maintenance, extra things to buy, etc.

I am not sure how you get that

Lets compare the two from a initial setup cost and ongoing cost



One tunze 6100 puts 3000 gallons + of flow in your tank ( Plus it can pulse ) all this at 45 W

I was running two T4' to get 2000 GPH ( head loss) + had to buy two seaswirls to get a decent random waterflow/

I doubt that any external pump even comes close to that much flow per watt

2X Sea swirls + Two pumps + plumbing + 4X Eletricity

You do the math

 

[Herbert T. Kornfeld]

tgreene,
Well, i suppose you are right, a closed loop CAN be run off of an overflow that is large enough to maintain the loop in the event that the sump pump is off. So, depending on the flow you intend with your closed loop, as an example...your 80gallon reef would prolly need about a 5 to 8 gallon overflow volume between the varied level outlets. Sorry, I read that you were using an amiracle "HOB" overflow box on a 125gallon...that wont be enough volume (no where near). Is there another that you are talking about in this case? I suppose the point of my post is that while it might be possible, it requires such a large overflow that for many it doesnt make sense. Also, one of the benefits we have been talking about here with the low-flow-overflow is the slow and direct removal of proteins from the water's surface and its direct feeding (or repeated passes through a skimmer before it is returned to the main tank) to a skimmer. Running a CL through the overflow does disrupt this cycle, and means more surface 'scum' gets recirculated through the tank.

The other thing is that for a 125gallon, were talking about having an overflow pump that only does 200-300gph, if that.

 

[kkris]

Any suggestions

Any suggestions

Herbert, Glad I found your post before I started my plumbing. I'm finishing a 150 gallon with 90 gallons of remote sump. Tank has been drilled for a closed loop. I'll be using the Sequence dart. B.H. holes are drilled for 2 - 1 1/2" Drains from a center overflow box yet to be built. My questions are: What size drain should I step down the piping to, and what flow? Any suggestions for an energy efficient pump handling 7 feet of total head? What impact does a large Beckett skiimmer run offa Genx have on this setup? Thanks, Ken