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Discussion Starter · #1 ·
I am working on redoing my 20 gallon tank, and I want to incorporate a CLS in my setup. The tank is going to be mainly (or only) SPS corals, so I know I need a good amount of flow. I am just not sure how much flow.
Also I wanted to have 4 outlets for my CLS, so we will need to take that into consideration. Lastly, I need to figure out how to setup the 4 outlets off of one pump wihout using an OM 4-way. Is that even possible.

So what size pump, and can it be done?
 

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glass or acrylic tank????

are you planning on comng over the top or can you drill it???

ARe you going to make it barebottom like you were talking about before??

If so you can get away with LOTS more flow becasue you dont have to worry about keeping the sand on the ground......

where are you going to put the pump??
 

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Discussion Starter · #4 ·
Fly Guy said:
glass or acrylic tank????

are you planning on comng over the top or can you drill it???

ARe you going to make it barebottom like you were talking about before??

If so you can get away with LOTS more flow becasue you dont have to worry about keeping the sand on the ground......

where are you going to put the pump??
It is going to be an Acrylic tank.
I would like to drill the tank. The returns would be hopefully 2 on the bottom and 2 in the middle back.
It will be a bare bottom tank. The rock is cooking as we speak.
The Pump (depending on size) will either rest on the floor, or on a shelf in the stand.

The stand is going to be about 30 inches tall.
 

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:thumbup: Sweet. Barebottom sps tank,........

id throw a mag 12 on there or even spend a little more and get an small iwaki and that should get you about 50x turnover after plumbing. Maybe even consider 1 spraybar across the bottom back and 3 returns across the top.

So no OM unit, have you considered a scwd to achive some random flow??? Geoff could prolly steer you straight with some eductors and use a much smaller pump even......

as far as your question "can it be done"..of course it can....a buncvh of different ways.......
 

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Discussion Starter · #6 ·
My initial thought was a mag 7 with some eductors. That kinda changed since the eductors can take up quite a bit of space. I like the idea of a spray bar, but I want the equipment in the tank to be as minimal as possible.

Back to the eductors, if I placed one on the return that would give me a good amount of surface agitation.

Also for my return pump I was thinking about using a Mag 3 coming from a 20 gallon sump. I also have a mag 5 laying around, but I am not sure if I want that high of a turn over rate.
 

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BGJ223 said:
My initial thought was a mag 7 with some eductors. That kinda changed since the eductors can take up quite a bit of space. I like the idea of a spray bar, but I want the equipment in the tank to be as minimal as possible.

Back to the eductors, if I placed one on the return that would give me a good amount of surface agitation.

Also for my return pump I was thinking about using a Mag 3 coming from a 20 gallon sump. I also have a mag 5 laying around, but I am not sure if I want that high of a turn over rate.
Spraybars done right cant be seen, they are hidden by your rock......

Do you run a canister filter for carbon or phosban??? One idea is to use the mag 5 for your return and steal a couple of hundred gph for phosban or carbon........

that mag 7 idea with eductors is going to give you more turnover than a mag 12 straight.

as far as the returns, what i have been doing on my last 2 builds is to take my returns over the top and to the front of the tank and then down.....i dont need the surface agitation but you could aim them up a little more than i do and achieve that surface agitation AND the plumbing is hidden by the canopy AND the back siphon issue is a non issue.

just a couple of ideas....
 

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Discussion Starter · #8 ·
Fly Guy said:
Spraybars done right cant be seen, they are hidden by your rock......

Do you run a canister filter for carbon or phosban??? One idea is to use the mag 5 for your return and steal a couple of hundred gph for phosban or carbon........

that mag 7 idea with eductors is going to give you more turnover than a mag 12 straight.

as far as the returns, what i have been doing on my last 2 builds is to take my returns over the top and to the front of the tank and then down.....i dont need the surface agitation but you could aim them up a little more than i do and achieve that surface agitation AND the plumbing is hidden by the canopy AND the back siphon issue is a non issue.

just a couple of ideas....
THe only problem that i can see with the Mag 7 and the eductors, is if I have the outlet split into 4, I will lose alot of flow won't I? Also the only way that I can see running 4 outlets on a CLS with out an OM 4-way, is to make a rectangle under the tank and have a T in each corner for the outlet. So the first 2 outlets in the chain would get the most flow, and the rest would get considerbly less.

Now I need to see if I can find some smaller sized eductors. I love how much water movement you get from them.
 

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Ill be honest and simply say i cant answer your questions about eductors. Thats geoffs(and others) ballgame. I just buy big enough pumps and keep all of the plumbing out of the tank and my outlets very low profile................

Om units and/or adequate size pumps i can hook you up with sweet flow, flow patterns, and plumbing ideas however. :)

The options available if you go with an OM unit are ENDLESS utilizing different plumbing configurations and different drums........

eductors cannot be used with any effectiveness with an OM, you need to just purchase your GPH up front
 

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Discussion Starter · #10 ·
Well what is taking Geoff so long?
Well thanks for the ideas Fly Guy, my head is just spinning with ways to plumb this thing. I can't wait until I get some equipment so that I can start a build thread.

So what do you think of a Gen-X PC-18000 pump for the CLS? 4750 GPH.
:)
 

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Discussion Starter · #12 ·

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Get the stats on that pump(that they dont list), i highly doubt it supplies enough head pressure to run even 1 eductor very well even if it only had one outlet. Eductors need a ton of head pressure to work.
I know this one can run ONE, maybe two depending on the pipe you chose....
http://www.marinedepot.com/md_viewItem.asp?idproduct=IK1133

i know its expensive, i just listed it so you could see the head pressure ratings.........

The reason OM units cant run eductors very well regardless of what pump you use is that it is a variable amount of flow to any given port at anygiven time......

edit........i thought that pump was new when i first looked......get the stats on it but i dont think eductors will even be necessary unless you want 100x turnover rate in that tank of yours.....
 

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Discussion Starter · #14 ·
well I put a bid on it, we will see what happens.
From my limited experience with eductors, they work better with a pressure rated pump, but you don't have to have one. I currently have one running on a Rio pump, and the thing really moves the water.

I really like the pump on ebay because of the 2 outlets. hopefully it is not a lemon
 

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you want to put an eductor on a 20g tank!!! i really think that it would not work. they do need pressure rated pumps in order to work, and they tend to start working at a 400-500gph. so you would be starting with 2000gph for one eductor!! :eek: you would be up to 400x flow rates with 4 eductors. i think it would be a deadly vortex in that case. :D

first off, what kind of 20 is this, the standard or a 20l or 20xh or what? i think doing what i did on my 125g would be the best bet. having the outlet for a CLS embedded in the LR. the problem is that it requires a lot of preplanning, but really keeps the maintenance low. it is the under the LR that all of the detritus problems occur. if you can get that under control the rest is cake.

you should be able have plenty of good flow with just 3 outlets. one under the LR, either in spray bar form or just a lot of flow out of a single nozzle like what i have. and 2 outlets up near the top of the water column.

the one under the LR should have close to 1000gph, this one needs to be the strongest. the other two could total 1000gph and be fine.

am i making sense? have you seen my build thread?

G~
 

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Discussion Starter · #16 ·
Geoff said:
you want to put an eductor on a 20g tank!!! i really think that it would not work. they do need pressure rated pumps in order to work, and they tend to start working at a 400-500gph. so you would be starting with 2000gph for one eductor!! :eek: you would be up to 400x flow rates with 4 eductors. i think it would be a deadly vortex in that case. :D

first off, what kind of 20 is this, the standard or a 20l or 20xh or what? i think doing what i did on my 125g would be the best bet. having the outlet for a CLS embedded in the LR. the problem is that it requires a lot of preplanning, but really keeps the maintenance low. it is the under the LR that all of the detritus problems occur. if you can get that under control the rest is cake.

you should be able have plenty of good flow with just 3 outlets. one under the LR, either in spray bar form or just a lot of flow out of a single nozzle like what i have. and 2 outlets up near the top of the water column.

the one under the LR should have close to 1000gph, this one needs to be the strongest. the other two could total 1000gph and be fine.

am i making sense? have you seen my build thread?

G~
I don't agree with the presure rated pump being the only way to drive an eductor. Also I have tested an eductor on a flow rate as low as 200 gph, and there is still a noticable increase in flow. Since the main way an eductor works is by having the stream of water sucks tank water into it's stream and pushes it back out. The only way I think for it not to work, is if you could not create a stream strong enough to move the stagnate (sp?) water. That is just my theory.

The tank that I want to do this on is a 20 tall tank, so 24*12*18?

I have seen your build thread, and I like the idea of the outlet under the rocks. The only thing I don't like about that, is to me it is some what of a waste in flow. I want to have water movement under the rocks to pick up the detritus, but I want that flow to also hit the corals and uper part of the rock work.

I am still not sold on the idea of the eductors, mainly because of size issues. I do however think they would be the best bet to help create random flow in the tank, and provide enough flow to help suspend detritus the falls under the rocks. My idea with the eductors would be 2 outlets on the bottom front of the tank, and 2 on the upper back wall of the tank. If I could provide roughly 250 - 300 gph per outlet, I think that I would have more flow than I would ever need. THe only scary part, is the flow that would come from the eductor be too much for the SPS coral?
 

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you can use a non pressure rated pump on an eductor, but when you do this you actually get less flow out of the eductor than if you had let the pump run out a normal nozzle.

do not confuse total flow with flow velocity, they are easy to mix up. ;)

the effective range of an eductor is bit long for a 20g also. it will just begin to really spread out by the time it hits the tank wall.

i feel that having that outlet under the LR is prolly the best thing that you could do for the corals most corals die because of a lack of flow at their basses. with a huge amount of flow coming up through the LR the bases of the corals are getting flow from all sides, including from below. it also allows complete clearing of all detritus under the LR mound. i think it is far from being wasted flow, i think it is more important than the open tank flow. hence the percentage of each.

G~
 

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Discussion Starter · #19 ·
I just don't see how an eductor would stop working (the way its supposed ot) if you don't have a pressure rated pump. I think I need to do some more research on my part.

I am going to take another look at your build thread, you know the one that does not have that many updated pictures. I am not totally sold on the outlet under the live rock, but it is starting to seem like a good idea to me.
As always,
Thanks for the info Geoff
 
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