river manifold in a 30X12.5 tank

Okay, we are making a river tank, and I am going to use the river tank manifold design. the tank is a 20L 30X12.5, and the river my natives are coming from is the Potomac River, the current is about 2-4 mph.
what size PVC and powerheads do I need??? and how many powerheads do I need??
I bought 1/2 inch pvc, is that to small?
Is 1 powerhead of about 100gph or a little more good enough??

thanks

Okay, we are making a river tank, and I am going to use the river tank manifold design. the tank is a 20L 30X12.5, and the river my natives are coming from is the Potomac River, the current is about 2-4 mph.
what size PVC and powerheads do I need??? and how many powerheads do I need??
I bought 1/2 inch pvc, is that to small?
Is 1 powerhead of about 100gph or a little more good enough??

thanks

anyone???
please help?

Haven't you already asked this question in a different thread?

okay, how strong of a current do you think the manifold will be with 1/2" pvc, and a Aqua Clear 20 or even a AC 10 if the 20 is too strong?

thanks, please help...

okay, after hours of research on md's dnr pages... I found out that the area of the potomac above dam #5 where I will be collecting is slack water, but in the tight bends where I will be collecting the water can move at about one mph. would a powerhead rated for a 10G get the job done to make only a slow current?

i know I am bugging all of you, but I have to get this tank setup and cycled, because my 1000 mile collecting trip July 4

Edited by DooSPX, 25 June 2008 - 12:37 PM.

you would only need a standard hang on the back filter to cause enough current for a standard slack water tank or even a 1 mph stream. I use a sponge filter in my swamp tank and it even causes some current with the bubbles breaking the surface.

when i put my aqua clear 50 on the short side, it didnt seem like it was much a current. the aquaclear has more of a waterfall than a bio-wheel.
it didnt even move a silk plant placed about 26" from the filter....

when i put my aqua clear 50 on the short side, it didnt seem like it was much a current. the aquaclear has more of a waterfall than a bio-wheel.
it didnt even move a silk plant placed about 26" from the filter....

If you keep the water level in the tank close to or above the AquaClear's weir, you will get quiet operation, but little current. If you keep the water level sufficiently below the weir, you will get noisy operation, but noticeable current.

I have undergravel filters in my riffle tanks, with the powerheads mounted low enough to blow across the rocks, rather than across the top of the tank. It works. However, I do have ambitions to do something better, with more powerheads and more current. The single powerhead concentrates current, rather than distributing it across the width of the tank, because it is a point source. It also dissipates across the length of the tank, since the undergravel filter is drawing the return in more or less uniformly under the whole tank. Your AquaClear will will also be a point source, concentrating the current. Also, since the return is directly under the weir, it will set up a circulatory flow, instead of a flow across the length of the tank.

Ideally, I think, to make a proper riffle tank, you need at least two low mounted powerheads in/near opposite corners (front and back) at one side of the tank, to create a current distributed across the width of the tank. Their intakes should be on the opposite side of the tank lengthwise, so that all current goes across the entire length of the tank without dissipation. This would eliminate undergravel filtration; sponge filters could be installed on the intakes. Using a single powerhead or over-the-back filter is a poor approximation, but it will give you some current, which will be good for your darters, and will be easier and cheaper to construct.

Your concept could be improved like this:
http://www.nanfa.org...es/zoller.shtml

The idea that I like best so far is this:
http://www.loaches.c...manifold-design

These links were posted recently in this thread:
http://forum.nanfa.o...?showtopic=5017

If you keep the water level in the tank close to or above the AquaClear's weir, you will get quiet operation, but little current. If you keep the water level sufficiently below the weir, you will get noisy operation, but noticeable current.

I have undergravel filters in my riffle tanks, with the powerheads mounted low enough to blow across the rocks, rather than across the top of the tank. It works. However, I do have ambitions to do something better, with more powerheads and more current. The single powerhead concentrates current, rather than distributing it across the width of the tank, because it is a point source. It also dissipates across the length of the tank, since the undergravel filter is drawing the return in more or less uniformly under the whole tank. Your AquaClear will will also be a point source, concentrating the current. Also, since the return is directly under the weir, it will set up a circulatory flow, instead of a flow across the length of the tank.

Ideally, I think, to make a proper riffle tank, you need at least two low mounted powerheads in/near opposite corners (front and back) at one side of the tank, to create a current distributed across the width of the tank. Their intakes should be on the opposite side of the tank lengthwise, so that all current goes across the entire length of the tank without dissipation. This would eliminate undergravel filtration; sponge filters could be installed on the intakes. Using a single powerhead or over-the-back filter is a poor approximation, but it will give you some current, which will be good for your darters, and will be easier and cheaper to construct.

Your concept could be improved like this:
http://www.nanfa.org...es/zoller.shtml

The idea that I like best so far is this:
http://www.loaches.c...manifold-design

These links were posted recently in this thread:
http://forum.nanfa.o...?showtopic=5017

thanks.... I was going to do the manifold, but with one small powerhead, then I found out that the river where I will be collecting is slackwater because it is above a dam....
so, now I am thinking about just the HOB filter on the short end of the tank.
the problem is the aquaclear return is soo short that the water has to be filled up to the lip of the rim on the toof the tank. but I love AC filters because they are so diverse in media you can use.
also, its not a riffle or rapids tank... MD's DNR calls this part of the river slack water, so the current is pretty slow... I bet it if you put something in the river, it will only move a 5-6 feet every minute.....

Edited by DooSPX, 25 June 2008 - 04:55 PM.

thanks.... I was going to do the manifold, but with one small powerhead, then I found out that the river where I will be collecting is slackwater because it is above a dam....
so, now I am thinking about just the HOB filter on the short end of the tank.
the problem is the aquaclear return is soo short that the water has to be filled up to the lip of the rim on the toof the tank. but I love AC filters because they are so diverse in media you can use.
also, its not a riffle or rapids tank... MD's DNR calls this part of the river slack water, so the current is pretty slow... I bet it if you put something in the river, it will only move a 5-6 feet every minute.....

got that problem fixed, bought a marineland bio-wheel, it is 2 inches deeper than the AC. that should work perfect for the slack water in a 30" tank.
thank you all so much for all the help and info you provided. !!!
you guys are great!!!!!!!

I think you've made a wise choice. Unless you are the fiddling type, the HOB on the side of the tank is a much easier route, and perhaps easier to maintain as well.

I think you've made a wise choice. Unless you are the fiddling type, the HOB on the side of the tank is a much easier route, and perhaps easier to maintain as well.

thanks, how well will val grow in just gravel only substrate? should I put flouritine (sp) in too???

Vallisneria is pretty adaptable (so long as that is what you really have and not Sparganium, which looks similar when submerged). Fine-ish gravel should be OK (smaller than pea). A lot of mulm is good. If you are just setting up, maybe put some crushed dried leaves under the gravel to get a good mulm bed started. But they will probably do OK without. You definitely don't need fluorite for Vals.

Vallisneria is pretty adaptable (so long as that is what you really have and not Sparganium, which looks similar when submerged). Fine-ish gravel should be OK (smaller than pea). A lot of mulm is good. If you are just setting up, maybe put some crushed dried leaves under the gravel to get a good mulm bed started. But they will probably do OK without. You definitely don't need fluorite for Vals.

thank you, where can I get crushed dried leaves? I live in florida....

Florida does have some deciduous trees, although I'm not sure which are so down there. But I see stands of them in the winter...

Florida does have some deciduous trees, although I'm not sure which are so down there. But I see stands of them in the winter...

thanks, what kind of leaves are bad to use?

Avoid conifer (needle) leaves, walnut leaves, and leaves from any plant known to be toxic .

And remember - you don't absolutely have to have them for Vals.