View Full Version : Overflow Design Question
NASAGeek
07/14/2016, 08:05 PM
Just bought a 180 gallon tank. 72" by 28" by 24"
It is not drilled yet.
I understand the rule of thumb on 10 times the tank size for minimum flow, but I've tended to be more successful with increased flow. So... let's target 2400gph.
Here's my question.... assuming I am going to follow BeanAnimal's design for the overflow, how big do the supply and drain PVC's need to be assuming I will have 2 supply lines and 1 drain line???? 1200gph each for the supplies.... and that plus some margin for drain.
Thoughts?
Any inputs are welcome.... now is the time to decide.... quiet is obviously important.
Tank will be used for reef aquarium mixed corals and fish. One supply on each back corner, BeanAnimal drain in the middle...
Thanks
Mark
Gorgok
07/14/2016, 09:44 PM
Supply size is usually pump based. Use a size bigger than the outlet of the pump, or in some cases quite a few sizes bigger if the manufacturer says to do so to get the flow out they claim. Bigger is better for quiet operation though, as it lowers flow speed (not volume) and as a result the friction which is what would cause most noise.
Siphon drain size depends on the drop (head) of the system and pipe size. Here is a fancy calculator that can give you theoretical maximums depending on size/height: http://www.beananimal.com/articles/hydraulics-for-the-aquarist.aspx
I would not go smaller than 1.5" on a tank that big myself, even if 1" at 4' could basically handle 2300 gph. I even have that on my 75 (with a flow aim of 1500 gph or so).
Lsufan
07/14/2016, 10:46 PM
I may of misunderstood u, but on beans design u will need three drains. A siphon which has a valve on it, an open channel with the airline and a dry emergency.
Good info by gorgonk on your returns and I would also go with 1.5" drains. I went with 1.5" returns & 1.5" drains on my 150 gallon & couldn't be happier.
NASAGeek
07/15/2016, 05:21 PM
Seems like 1.5" bulkheads and 1.5" returns is the best choice... thanks much. BTW... typo above.... 210 gallon display tank... not 180, doesn't change the answer though.
THanks
M
Merv 49
08/04/2016, 11:50 PM
I am new to all this and in the process is setting up a 200 gallon tank I purchased on Craigslist recently. The tank is Drilled for Bean Animal overflow but when I bought the tank I had no clue about the actual overflow size. I knew the five holes in the overflow box was for bean animal but I didn't check the size. Upon further learning from numerous videos and forums I find now that my overflow holes are drilled for one inch PVC bulkheads and the returns are drilled for 3/4 inch bulkheads. I'm sure the returns are fine but now I'm worried that the overflows may be to small. What do you think?
I've considered perhaps removing the overflow walls and siliconing a glass patch over those holes and drilling the back of the tank for a ghost overflow is the one inch overflows won't work.
Any ideas or suggestions would be appreciated. The tank is 72X24X27.5
Thanks
LXXero
08/05/2016, 12:02 AM
is the overflow box coast to coast?
1" will do 2000gph full siphon @ 3ft head. At 4ft head it's like 2400gph. How tall is your stand? I suspect you'll be in-between those two numbers.
plus the trickle would be good for another 600gph, but it wouldn't be "quite as silent" at that flow rate, lol. and you'd lose some notion of redundancy with the trickle doing that much flow.
even so, i'd say you could do like 2200GPH+ all day with that setup
do you think you need more flow than that? that's like 10-12x flow through the sump, and most people say you only need 5-6x which would be 1000-1200GPH. I think you'll be fine. 1.5" just buys you more margin for error, but I think for 200 gallons @ 6x turnover you still have at least 800-1000GPH margin, which is waaaay more than enough in my book.
I think you're fine. even if you wanted to run 10-12x tank volume flow rate, you'd still be fine, you'd just be running near max capacity.
I have a 120g and i used 1.5 bulkheads but i had to reduce the siphon/trickle down to 1" later, so i really only get 1" worth of flow. Meanwhile, my pump is 1800GPH (overkill, but i drive a manifold) and I can put 1200-1300GPH through the 1" drain all day long and there's clearly a ton more capacity, as i have the gate valve dialed down most of the way.
Merv 49
08/05/2016, 12:39 AM
Thanks for the insight. The overflow box is about 16 inches wide. My tank stand is 35.5 inches tall and the tank is 27.5. I was wondering if less flow is acceptable as everyone seems to push for the max. I'm going to go ahead and use what I have and try not to worry about it. lol My return pump is variable up to 3100 gph so I can adjust for whatever flow I can get. I will do what I can to eliminate any bends coming out of the overflow to get all I can get out of it. Thanks for the encouragement.
LXXero
08/05/2016, 01:25 AM
Thanks for the insight. The overflow box is about 16 inches wide. My tank stand is 35.5 inches tall and the tank is 27.5. I was wondering if less flow is acceptable as everyone seems to push for the max. I'm going to go ahead and use what I have and try not to worry about it. lol My return pump is variable up to 3100 gph so I can adjust for whatever flow I can get. I will do what I can to eliminate any bends coming out of the overflow to get all I can get out of it. Thanks for the encouragement.
hmm 16" wide, how deep is it though? does it have teeth, or is it just a straight overflow? I suspect if it does have teeth, those could be yet another GPH limiting facter, well, it will just set the water level higher, i suspect at more than 1600GPH you'll have water pretty far up the teeth, but how deep the box sits into the tank will also determine that, my overflow is like 1" by 18" so there isn't much flow in from the sides at all, versus say, 16x4" would almost be like adding another 8" of skimming surface, if that makes sense? (16+4+4 for each side)
I wouldn't be surprised if you can run the pump at 3100gph maxed out no problem with that setup. Cause you gotta figure - after head loss - it's gonna be like 2500gph if you're lucky...and that setup with the trickle and one line as the siphon, it'll definitely handle it, but probably a bit noisy since you'd have the trickle line going at that flow rate.
okay so you got nearly 3ft of stand and about 2ft or so of tank. The real measurement would be how far down from the top of the tank, to the final water level in the sump, that'll be the number that determines your flow rate...the closer to 4ft+ you get, the more you get closer to 2400-2500gph, i suspect it's probably 3.5-4ft range and you'll prolly be able to get nearly 2200-2400 through the siphon alone, and that means you still can do another 400-600gph through the trickle tube without even having the emergency kicking in. You'll be good.
See the calculator here, check the "submerged discharge" box to see what i mean in terms of how to measure it. You can even drop in your numbers there and calculate it yourself:
http://www.beananimal.com/articles/hydraulics-for-the-aquarist.aspx
And yeah, least amount of bends in the drain lines as possible. also avoid horizontal runs if at all possible, verticals are always preferred, and diagonals second to that.
Meanwhile, on your returns from the pump, haha, don't worry about that at all. sounds like your pump is more than overkill, so use all the 90s and bends and curves you want on the return lines, hahaha. it wont hurt to kill some flow off your pump....most pumps like a little bit of pressure anyway. of course be reasonable, but i wouldn't worry about this as much with your return lines.
also i've always heard 5-6x for saltwater/marine sumps, which again is waaay below what 1" can handle. The only time i ever hear people talking 10x is usually talking overcrowded cichlid tanks where you purposely overstock the tank to keep aggression down and then overfilter the hell out of it. i've seen people go way overkill on those setups. but not usually for a saltwater sump....
Lsufan
08/05/2016, 10:57 PM
I agree with everything LXXero says if u already have holes for 1" bulkheads drilled in the tank already.
In the op's case I would drill for 1.5" bulkheads though. I wouldn't drill anything less in my tank if it was a 210 like the op's. I wouldn't limit myself if u have the option to go 1.5" I would do it. A 1.5" open channel will be a good bit quieter too.
I like to run a little higher flow through my sump so I run at about 8 - 10 times turnover on my tanks but a lot of people run only 3 times turnover with great success to. There's not a set number, it works well from 3- 10 tt.
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