340 gallon octagon tank

snookman · Post by **snookman** » 20 Nov 2004, 20:35

ok...here's the deal...I'm building a freshwater octogon tank about 56.5in in diameter and 30in tall. I'm also building a stand and canopy for it. The engineering for all of this is already figured out. My problem is this...I am wanting to create a "circular riverine" style tank via powerheads. My thoughts were to have the current flow in a circle arround the tank. I am also planning on building a wet/dry with sump and all and am wondering if I should keep the "current" powerheads in a seperate loop or if they should be in the loop with the filtration. Also, I'm curious as to how much heating I would need for this. Any help would be greatly appreciated.

magnum4 · Post by **magnum4** » 29 Nov 2004, 19:44

I'm not 100 percent sure what you are asking? Should the power heads be in the tank or in the filter is that it?

Apart from the heating question 2x 300watt will be enough.

snookman · Post by **snookman** » 30 Nov 2004, 00:31

therewill be a powerhead return from the sump of course, but i'm wondering if it would be necessary to add a seperate powerhead just for current.

Post by **Barbie** » 30 Nov 2004, 04:53

IMO, if you just used a larger than normal return pump, and built a spray bar that went from top to bottom of the tank and pushed flow in one direction, you wouldn't need additional powerheads in the tank. Where exactly is the overflow for the water returning to the sump?

Barbie

snookman · Post by **snookman** » 02 Dec 2004, 01:00

I'm putting the tank in a corner with a wall on the back and left sides leaving a triangular gap in the corner for the overflow box and plumbing down to the sump. I thought the same thing with the vertical spraybar and i'm just wondering if it'll be enough to move the water at a good enough rate. I don't want the raging Congo river or anything though. I have a very vague diagram here...beware of the "hugeness". It was made on a 8.5"x11" template on Microsoft Publisher. If anyone knows how to shrink it, by all means do so.

WhitePine · Post by **WhitePine** » 02 Dec 2004, 05:35

I would push at least 1000 gallons on hour.... I currently have 2 aquaclear 801(400 gph each) and a eheim with spray bar(240 gph) and it dosen't seem like it is enough in my 55 gallon tank! IMO

Post by **Barbie** » 02 Dec 2004, 07:51

I think you'll find you have to point the spraybars out a bit from the sides, so you don't get diffusion as the water flow runs into the corners. That shouldn't mess up your plans though. I agree that you'll need at least 1000 gph, but I'd actually probably shoot for closer to 2, if it was me. You're going to have the returns spread through numerous holes down the length of that spraybar, which will diffuse the flow quite a bit. I shoot for turning the tank volume over 10 times an hour in 55 gallons or smaller, 7 times in 180 or smaller, and 5 or more for larger than 180 (just roughly for maintenance type accounts). With the diffusion you're going to be having, and the amount of current you'll want to establish, plus the head height, you're going to be looking at a pretty serious pump, but it's certainly manageable. Good luck!

By the way, in the MGM Grand Hotel in Las Vegas, they had a tank for a schooling fish in a cylindrical tube with heavy flow around in a circle. You might do a search and see if there's any information on the equipment used? I've never really been a morning person, but my hubby got to watch them do filter maintenance and clean it one morning while down fetching breakfast. You know you're a fish junkie when you'll stand around just to watch someone take apart a filter!

Barbie

snookman · Post by **snookman** » 03 Dec 2004, 04:14

lol...very true, Barbie. thanks for the advice and thanks to whitepine for the the smaller image. I figured as much on the diffusion...this is why i'm concidering 2 return pumps...possibly 2 sumps, hence 2 overflows and 2 spraybars.
This would eliminate clutter in the main tank, at least if i didn't have a need for another powerhead in the tank. I could also double up on lower wattage heaters. this way if a return pump or a heater fails, i still have a litle back-up. do you have an opinion on whether i should use 2 sumps or not? i've speculated that i'll need arround 12-15 gallons of bio-balls cumulative...does that sound right for a 340 gallon?

MatsP · Post by **MatsP** » 03 Dec 2004, 10:51

I'm by far not an expert, but I've read more than one place that having two filters also mean less disruption when you clean the filters, as you clean one at a time with some period of resettling in between. That way you don't get as big a drop in active nitrobacteria, and you end up with a more stable system.

Of course, you also have half the filtration going if one system is out of order.

I think that's a good idea.

--
Mats

Post by **Barbie** » 03 Dec 2004, 15:40

I'd go with one large sump, personally. Two is just going to give you more chance of some form of mechanical failure. You can always run two pumps for returning water in one sump. Getting two sump levels balanced would be a real pain in the keester at first, and that's an overkill that doesn't really need to be done, IMO. In a wet/dry filter, you aren't ever going to be cleaning your biomedia anyway, just the prefilter floss and sponges. That will negate you needing to worry about killing back any bacteria.

Unless you plan to REALLY overstock that tank, you're going to find it's hard to impact that bacteria enough to show any ammonia or nitrites anyway, IME. That big volume of water will spoil you for anything small again ;) Your bioball calculation sounds correct. I usually shoot for at least a gallon to 30 gallons of water, or a bit more. I also use coarse filter sponges in a second drip tray under the initial floss media when I can, for additional mechanical and bilogical filtration in one step.

Barbie

Barbie[/color]

WhitePine · Post by **WhitePine** » 04 Dec 2004, 00:06

I think I would just forget the spray bars and run it straight from the pump!!!

snookman · Post by **snookman** » 07 Dec 2004, 01:06

for return pupms i was looking arround and am thinking along the lines of 2x1000gph pumps like the one on this link--> http://www.petmeister.com/item2327.htm
any opinions on brands of pumps?

magnum4 · Post by **magnum4** » 07 Dec 2004, 19:57

How high is the maximum lift your pumps are going to make?

Because 1000gph is only at zero head. After the lift i suspect you need the flow will be considerably less.

Eheim make good pumps IMO.

snookman · Post by **snookman** » 08 Dec 2004, 00:09

Sump will be under the tank in the stand...stand will be 24in high and the tank will be 30in high...so i'm guessing 36-40in of vertical plumbing from pump to spray bar.

magnum4 · Post by **magnum4** » 08 Dec 2004, 20:29

So you really need a pump that can deliver 2000gph at a height of 40". It might be a good idea to go to your LFS and check out the flow rate charts on the side of each box.
Also have a look at the pond pumps. OASE make good pumps suitable for your design.

BK · Post by BK » 09 Dec 2004, 02:08

is the tank drilled to accept the spray bar or is it going over the side/back of the tank? Have you considered using an external pump rather than a submersible one?

snookman · Post by **snookman** » 09 Dec 2004, 19:49

tank is not drilled...and as for an external pump, i/m not following you on how that would work. are you saying drilling the sump and having the pumps mounted outside of it? i do know that powerheads, submersible or not, "push" a heckuva lot better than they "pull" so i would want the intake immediately into the water with no plumbing there except a prefilter sponge or something to keep any particles that get past all other filter media from tearing up my pumps. either way i'll need to "push" water up about 40in of plumbing.

BK · Post by BK » 10 Dec 2004, 01:28

i mentioned external pumps because many of them can pump more water and to higher hights that powerheads and submersible pumps. i prefer the cs velocity pumps (now labeled as blueline or some thing like that after cs went belly up). the sump wouldn'd need to be drilled. just use a siphon/u-tube to get watter to the pump and put a check valve before the pump so it doesn't loose siphon or backlfow if power is lost.

snookman · Post by **snookman** » 10 Dec 2004, 21:54

a siphon on the sump?? you mean in a fashion like from tank to overflow??

BK · Post by BK » 11 Dec 2004, 04:28

yeah, except from sump to pump. is the sump glass or acryllic?

snookman · Post by **snookman** » 12 Dec 2004, 05:46

glass. it's a 55gal long.

BK · Post by BK » 12 Dec 2004, 08:40

i've had bad experiences with submersible pumps so i am biased towards external (particularly cs velocity pumps). im my experience most submersible pump are terribbly noisy/"vibraty" once you get over 250-300 gph. submersible pumps do however eliminate the siphon/tank drill and in that way make things easier. i personly haven't used a submersible pump over 500gph i would use\trust in a tank unless i had no other choice. i have a Quiet one 4000 and several other higher gph powerheads/pumps and all are terribly noisy and imo poorly constucted or engineered. as an side i noticed quite a few quiet one pumps of all sizes/models on clearance at dr foster & smiths outlet store due to customer returns last time i was there. good luck with your tank wich ever way you go. Some pics and final specs would be neat once you get it finished.

snookman · Post by **snookman** » 17 Dec 2004, 01:23

here's a link to both the diagram of the tank and a diagram of the wet/dry i'll be building for it.
http://photobucket.com/practice.php?id=535lg