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DIY Closed Loop Woes

S

Subliminal

NJRC Member
So, this weekend I decided to try setting up an external closed-loop system on my 29g reef.

Objectives:

* Get Powerheads out of tank to alleviate noise/heat
* Incorperate the SCWD mavemaker into the system.
* Keep whole system ~$100

So, I headed to the not-so-local superstore around these parts, right across the border, into Pennsylvania, and another 50 or so miles.

After spending some time in the store (and about $100 over my budget), I ended up with the following:

Enough plumbing pieces to make a 1/2 inch PCV standpipe
Enough soft line tubing to plumb the whole thing
Mag 7 pump
Various nipples, ball valves, etc...
SCWD wavemaker
2 return pipe u-bends.


So, I head the hour+ home and get to setting it up.

I start to take pictures of this wonderful DIY setup I'm creating...but then stuff starts going wrong...horribly wrong.

Well, the first night ends up in the whole thing plumbed and ready, but the pump leaks and won't hold a prime.

DAMNIT!

Now, because the store is so far away, I end up running to petsmart and buying another pump that's smaller, but will serve the same purposes.

That pump doesn't leak and holds a prime...but of course doesn't have enough pressure to replace my two mj1200s.

So, safe in my knowledge the pump is just bad, I decide to call it a night and return the pump the next day.

So, the next day I trek back to the store, swap the pump out, and also decide to buy enough plumbing parts to redo my standpipe in 3/4 inch.

Well, I get it all together and guess what...the new pump leaks exactly where the old pump leaked.

Well, closer inspection shows me that the ball valve i installed directly on the pump was actually hitting the output housing and pulling it away from the body of the pump leaving a small area for it to leak.

So, I fix that scenario and no more leaks.

Hooray! I'm in business, right?

Well, the system works, it pumps water, alternates outputs, etc...

But what it doesn't do is produce anywhere NEAR the output I had hoped for...which is basically around 5-600 GPH...or roughly the same as the 2 MJ1200s. And this with only 2 feet of head.

So, I leave the system running, plug my MJ1200s back in, and walk away in disgust...

Which is where I'm at right now. Except I ordered a new pump and a new scwd from a place with a good return policy to see if this equipment is the issue or what.

I hate it when good projects go bad!
 
Phyl

Phyl

Officer Emeritus
Officer Emeritus
I'm so sorry. I could have told you that (about the SCWD). I hate those things. I think I have one I could have given you (unless I gave it to the last person I recommended against trying it). When we had ours in use we needed to run it with a mag9 to get enough flow for our 600gph overflow. Of course the heat that a mag9 will generate should leave you without needing a heater in the winter. On a small tank, that's not a good thing in the summer. Mags are water cooled and not pressure rated.
 
Phyl

Phyl

Officer Emeritus
Officer Emeritus
The only think I can think is that he was only looking for 350-500gph of flow? He also suggests using 1" pipe on the outlet of the mag7 to prevent constriction. It is possible that you'd get better flow with the larger pipe diameter.

Probably cheaper to return/replace the pump at this point to an air cooled, external type pump.
 
S

Subliminal

NJRC Member
Well, I DID order a new pump, A little giant or somesuch that promises more flow, but honestly if I'm getting 100 GPH out of this setup right now, I'd be surprised. I really don't understand the whole thing.

At lunch today, though, I'm going to just stick the pump itself in a full 5g bucket and see how it pumps to a second bucket.

The whole thing was just a real let down in output, and i'm just more than a little surprised.
 
Phyl

Phyl

Officer Emeritus
Officer Emeritus
Did you check it without the SCWD? Maybe that's disfunctional?
 
S

Subliminal

NJRC Member
Well, closed loop is up and running. Made a THIRD run to PA and replaced it with a Iwaki (sp?) pump.

Still not quite as much flow as I had hoped for, but we'll see how it works for a while. Maybe I need to go for smaller outlet tips to up the flow rate.

Or maybe it needs to break in.

Or maybe I STILL have the wrong pump. ;)
 
M

mladencovic

The SCWD MUST reduce the flow significantly, that is how they work. My understanding is that 50% flow reduction is a norm (from what I have seen on the web).
 
S

Subliminal

NJRC Member
50%? I've read more along the lines of 15-20. I think they publish 15%, but not sure.

Anyway, I suppose it's possible...it definetly doesn't flow what I'd like it to, at any rate.

Also, it flows about 75% out of one side and still flows out the other when it switches.

That didn't make much sense, but it never switches totally to one side.

Anyway, I wrote a whole write up here. There's some stuff about the forum there, but if you just scroll down, the whole things should be there.
 
R

reneeRN

get rid of the squid. then place a ball valve to regulate the two outputs. for awesome flow (diffused) get yourself two penductors or eductors for the output.
 
S

Subliminal

NJRC Member
Actually, I just got a better pump and the scwd is working great. Corals seem happy, flow seems adequate, etc...

Just took a little time and rebuilding...and multiple trips to PA to the store. ;)
 
Phyl

Phyl

Officer Emeritus
Officer Emeritus
So what pump did you end up with at the end of the process? What's the GPH rating on it?
 
S

Subliminal

NJRC Member
Honestly, I wish I would have bought a little stronger of a pump and then i could have throttled it back if necessary. For some reason I just like a lot of flow. ;)

Anyway, I got the Iwaki 20RLXT It says ~880 @ 0 head.
 
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