SCWD/external powerhead possible?

[skylsdale]

Alright, I've got a 10 gal up and going and I'm trying to figure out whether a few ideas are possible. I'd like to get some of you guys' input/experience on something. First off, the tank is in my twin boys' room, on a dresser. This means that everything pretty much needs to be self contained, or at least able to fit in the few inches of space behind the tank. Plans for the tank are to add a few Pocilloporid spp. and just let the colonies take over the tank.

I am hoping to put a little drilless SCWD system on this thing, but I don't need absolute hardcore flow (and the budget is pretty tight) so a monster pump isn't really a possibility. I was curious if you guys think it would be possible to use some sort of Maxijet or similar powerhead externally to run the SCWD. My first concern is how watertight seals could be made. The second is whether 1200 GPH is going to really be all that much flow in the tank. I would have either two returns in the back corners of the tank, or possibly two spraybars on either side just below the water's surface. Thoughts on this?

I am also looking at one of the lower end Eheim or Mag pumps, but I was curious if they would add much heat to the system? Are they pretty quiet?

Thanks guys!

 

[Anonymous]

If you use a MJ 1200, here's how to make a watertight seal: Use a gang of teflon tape around the inlet and outlet of the pump, and shove some vinyl tubing around it. Use metal hose clamps around the tubing...voila!

I would do the two spraybars, rather than two returns from the corners...unless you're going from the front corners. Returns at the back corners just direct the flow at the front glass, not the corals.

I've never used an Eheim or Mag, but they both get good reviews.

 

[skylsdale]

Thanks Matt. I've never used an MJ1200 before--do you think it will be enough flow through the two spraybars? Maybe I can put a smaller powerhead in the tank as well, just to keep some choatic flow going.

 

[Anonymous]

I second the spraybars. You could easily leave the pump in the tank, and just bring the plumbing up and over the back wall. Then plumb the return lines whereever you want them.

B

 

[Anonymous]

Personally I like to keep everything I can hidden. I hate the look of PHs, heaters, etc. in the tank, especially in a nano where it's even more obvious. For Pocillopora you can probably get away with the single MJ 1200...iirc it's 295 gph, but you'll be losing some due to flow restriction. I always like to do two pumps in case one fails, so I would go a big one on the SCWD and maybe a smaller one just to stir up the surface. Just my 2 cents...


OOOh, by the way, I'll try and find a neat link for ya...

 

[Anonymous]

http://www.sparklingfloorservice.com/ta ... dloop.html

He uses a Mag, but the idea is the same. Some very good advice in terms of what plumbing parts to add for easy maintenance. It would be easy to have two separate pumps draw from the same intake as well. I would never have that thing hanging off the back of my tank, but if you can't have a sump or external compartment, this would work.

 

[skylsdale]

Yeah, I was planning on using Melev's design for this. So Matt, what are you suggesting for the second pump: putting it in the tank, or rigging something else?

I think I'll go with the spraybars. That was my original intent, but I wasn't sure if something as small as a Maxijet would be too weak to really push any decent amount of flow through them.

 

[Anonymous]

Well you would want to have lots of small holes so as not to restrict the flow. My thought was that you could add a second pump to that closed loop--with the same intake but with two(or one) separate return lines. See where that elbow goes into the intake of the pump? Imagine that being a tee instead of an elbow, and putting a pump on the other side as well. As long as you had a large intake pipe diameter (I'm guessing 1"?) it would work.

Just another thought... up at the top of the whole unit, where that cap screws off to start a siphon--if that were a section of large diameter pipe you could easily throw a heater in there, drill a hole in the cap and seal it all.

If you can't tell, I really hate the look of pumps and heaters inside the tank.

 

[skylsdale]

That's just dirty...and absolutely PERFECT. I hate having things in the tank as well, and those are some fantastic suggestions.

 

[Mihai]

I am a bit worried that in the case of a power failure the pump will loose suction (and not regain it once it restarts) - i.e. it's not self-priming. 2 bad things: stuff will die in the tank and the pump will die as well.

M.

 

[skylsdale]

What if I didn't have a siphon tube--it just took water straight from beneath the surface and emptied it back beneath the surface? Then it would never lose prime--there would always be water in it, right?

 

[Anonymous]

depending on the height of the plumbing, It will empty anything above the tank waterline. What you have to do is make sure there is more water than air in your intake tube. WHen the pump restarts, it will have enough water to get primed before it hits the air pocket. ALSO, you want to make sure the intake is actually taking in water before the air pocket hits the impeller.

B

 

[Anonymous]

What Bingo said. It should work just fine in a power failure.

 

[Mihai]

What Bingo said kind of makes sense, but it's all too vague for me. Do you have a reference?
What I mean is: "It will empty everything above the waterline". It can, but it doesn't mean it will, does it? When does it? Second, "more water than air", how do you measure that? by the inch?, then I'm confused by the intake taking water before the air hits the impeller: how can you make sure of that? The distance between the intake and the impeller is fixed. And why does it matter anyway?

Thanks for the help,
I'm thinking to making a closed loop without drilling my 90gal so the discussion is not purely academic.
M.

 

[Anonymous]

What Bingo said kind of makes sense, but it's all too vague for me. Do you have a reference?
What I mean is: "It will empty everything above the waterline". It can, but it doesn't mean it will, does it? When does it?

Second, "more water than air", how do you measure that? by the inch?, then I'm confused by the intake taking water before the air hits the impeller: how can you make sure of that? The distance between the intake and the impeller is fixed. And why does it matter anyway?

Thanks for the help,
I'm thinking to making a closed loop without drilling my 90gal so the discussion is not purely academic.
M.

After thinking about it, If all ins and outs are submerged far enough they can't suck air into them, they won't drain. If air can't get in and break the syphon, it won't. IF the pipes can't 'suck air' from anywhere, they won't be able to let the water out the pipes. Doiing so will only suck in more water from another pipe.

IF however air can get in, (like an outlet is too close to the surface,) Anything that is higher than the water line (Yellow Boxes) will drain if air can get in. IT's not a problem in the drawing, because the intake is the only part we're concered about. Also, if the intake does break syphon. it has a lot of water(green line) to suck through the intake pipe before it hits the air pocket left by the water leaving( back to the yellow box above the intake-if it breaks syphon, the pipe will fill with air,). All water below the edge of the tank will still be in the pipes.

got it? any more questions?

 

[Mihai]

Great insight: if the inputs and outputs are submerged there is no break in the siphon.
I kind of agree with the analysis for the case where air gets in, but I'd still say that you never know what happens once the air hits the impeller. It's just too messy to analyse.

Thanks for taking the time to explain, now it's a lot more clear.

Mihai

 

[HClH2OFish]

Try emailling the question to Marc....IIRC he may have answered some of the questions about that SCWD unit re:siphoning....

 

[Anonymous]

I use a scwd and maxijet 1200 on my nano

The top two back corners are drilled, and the center is drilled for the pump intake.

The flow alternates due to the scwd, so directing the returns at a coral is a non issue, the flow in the whole tank will rotate



Here's a pic of the setup

 

[HClH2OFish]

Where do you get those sweet bulkheads at?

 

[Anonymous]

who me? If directed towards me, they are standard 1/2" threaded bulks, both ends threaded, with the nozels screwed in, most places sell the nozel, standard linkloc (I think that's what they call them)