DIY Group Project - Eductors

[Geoff]

Charlie- do not think that a 50 would do that. i think that a 50 would have a hard time pushing 2, it should but would not be very impressive.

a 70 would do 3 no problem though.

with the outlets 12" above the bottom of the tank and each outlet probably pushing close to 2500gph per eductor that should keep a BB tank pretty clean.

to make it even more efficient you might want to build up the back tank edge with some extra silly cone to make it a ramp for the eductor flow. that way you will not get any micro eddies at the back glass, bottom glass boundary.

G~

[charlie]

Originally Posted by Geoff

Charlie- do not think that a 50 would do that. i think that a 50 would have a hard time pushing 2, it should but would not be very impressive.

a 70 would do 3 no problem though.

with the outlets 12" above the bottom of the tank and each outlet probably pushing close to 2500gph per eductor that should keep a BB tank pretty clean.

to make it even more efficient you might want to build up the back tank edge with some extra silly cone to make it a ramp for the eductor flow. that way you will not get any micro eddies at the back glass, bottom glass boundary.

G~

Thanx, I got to thinking after I posted about the 55. Oh well, what's another pump????? I like the idea of building something up in back, I am gonna have to take the darn thing apart anyways.

[jenajet]

Can I do this on my 90? I have a mag 9 for my return. The return is split with two lock lines. Would I do better with something like this? It seems simple enough, just wondering if the pump is strong enough to do what this modification would do. Or maybe up it to a mag 12. I want to increase flow without a close loop. I was thinking of getting two of the hydor koralia 4's, but if I can increase flow just by using eductors, even better. I had never even heard of these till coming across this thread.

[Geoff]

what is the overflow rated at? this will be your determining factor.

two eductors will not work on a Mag 9. one would barely work. a Mag 12 would run an eductor, but not two real well.

when connected to a good pressure pump, an eductor can add some serious flow. if you can move the return nozzle to one side of the tank and add a DIY eductor, you will get good results. i would not put an eductor in the middle of a 4' tank. the flow would be crazy.

a Velocity T1 or T3 would really get things a flying though with one eductor. one eductor on a T1 or T3 would add at least 2000 to close to 3000gph of flow to the tank. while still only pumping 400 to 600gph through the sump.

G~

[jenajet]

not sure on the rate of the overflow. How would I figure that out. Probably just do the hydors on this one and plan some type of eductor on the big tank when I start building. I won't want to go changing out plumbing with this tank when it is going so well.

[Geoff]

the size of the bulkhead will determine the flow of the overflow. if it fits 3/4" pipe than it is around 350gph. if it is 1" than 600gph. for that size tank it is most likely 1".

when using eductors they really cut down on what a pump can push. so a pump that is normally rated for 1200gph could easily be used as a return on a tank with a 1" drain if an eductor is used. this depends on the pump, so some research is involved, but not real difficult.

a Velocity T3 as a return would really get the flow going. this pump will be pushing easily over 2000gph of flow with only about 400-500gph through the sump.

G~

[jenajet]

Okay, found a 6ft 175 gallon with dual overflows. How is the best way to run the returns using these eductors. I will post some pics of the current return which I want to scrap, they are gunked up bigtime. Should I use two different pumps on both returns or get a really big pump. I havn't built my own return system before and want to do the best I can without alot of $. This will be a fowler.

[Geoff]

first question is what size are your overflow drains. this will determine what pump you will need for your returns. you can easily put a couple of eductors on a return as long as you pick the correct pump. there are lockline eductors if you want to go that route since it looks like you have lockline already run. not a big fan of returns not run over the back of a tank though. or at the very least make the return go above the water level so that you can keep the drain back to a minimum when the power goes out.

i do suggest using eductors on the drains though with such a large tank. you will need the oomph.

G~

[jenajet]

I will have to see but I am pretty sure they are 3/4 inch. So do you think it isn't a good idea to do eductors on a 175 gallon tank. I am trying to avoid adding more powerheads and just using the returns for flow. This is a fowler so I don't think I need the extra flow that reef tanks do so am I overthinking it here.
Don't think I am keeping those locklines cause they are pretty nasty. I can build some other return which is why I am looking into this type of return modification.

[jenajet]

What do you mean eductors on the drains? How would that work. I thought these were just for water coming out the return.

[Geoff]

i think eductors on a 175g tank are a great idea.

we need to figure out how much flow the drains can handle to determin the pump needed to push 2 eductors and still have a low enough flow so the tank does not overflow.

you really think the drains on the tank are only 3/4", i would think that they would be 1". we just need to make sure which it is.

G~

[jenajet]

I sent an email to the man I am buying it from to double check. I may very well be wrong. I tried to look thru oceanic but not getting anywhere there so will just wait for his reply.

[jenajet]

Okay drains are 1 inch and the returns are 3/4 inch. I had them backwords.

[Geoff]

that makes sense. so we have a max flow rate of 1200gph to work with for the return. this gives us some options. i will need to check the Iwaki pumps and the PCX pumps to see which would be the best bets. we should be able to get over 4000gph of flow in the tank using the eductors.

G~

[jenajet]

That's what I wanted to hear! So will each return go on their seperate pump? There is one on the right and one on the left. And it is a 6 foot long tank. I assumed seperate pumps would be best.