Speed drain-fed scrubber

I know it is often encouraged that one use a dedicated pump for their scrubber, but I am running out of electrical real estate and I don't think my landlord would appreciate an overhaul of the wiring. So, I'm hoping that this is a good idea and that I can get some good insight into the whole thing by asking those who've already tried this. So, the plan is to feed the scrubber via the overflow. I know that the potential for clogging is a problem, but the new system I'm setting up (after being out of the hobby for about 8 months) will have a speed drain-style overflow. There will be 2 drilled bulkheads in a single corner overflow box. There will be a ball valve on the scrubber, allowing the water level in the overflow to rise to a certain, controllable level. As a safeguard, the extra unobstructed bulkhead fitting will be there to prevent any potential disasters if the scrubber were to clog and back everything up.

The system in question will be a 40g breeder that I had before. I'm looking at a roughly 7-8" length of screen and about 8" or so tall, which should be more than covered by the added flow from the speed drain. I'm using a nice Tunze silence pump (the 600gph one, I think) that I had throttled on my previous small setup. I'll be using the previous little clamp-on fixtures and 40w CFLs that I had brand new in the box. This one will be a bit more modestly sized compared to my previous one, which was on the same tank. It did a little too well and I couldn't keep up with enough food to satisfy the needs of the scrubber.

So, any input would be greatly appreciated. Please let me know if this is feasible or at least sounds reasonable, as well as any other tips, critiques, etc. In the meantime, I'll be looking at some of the designs so that I can implement some better splashguards, ease cleaning, etc.

What's a speed drain?

Oops, I should've clarified. Sorry about that. I don't know what they used to be called, as I used them many years ago, too, but they call them speed drains or "herbie" speed drains now. They were originally designed to feed more water into large skimmers and make a quiet overflow/reduce bubbles. Here's the general premise:

http://i188.photobucket.com/albums/z...ps94891a05.png

When tweaked just right, the water level will be just below the safety drain and all the force of the water will go down into the scrubber (it also allows you to increase the flow from the return). If something causes a clog, the water is routed to the safety drain, which is the same size as the primary drain and can handle the water flow. These setups allow large quantities of water to go through the overflow, since they are considered full siphons.

I wouldn't have any drain at the bottom of the display.

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Originally Posted by SantaMonica

I wouldn't have any drain at the bottom of the display.

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It won't be at the bottom, but within a sealed overflow box.

I think he has it in the bottom of the overflow box.

There is no big deal running a scrubber this way. I have not had a slot pipe get clogged. But theoretically, it can happen, if you have a fish/snail/anemone make it to the siphon intake and it gets sucked down to the scrubber. A snail could get wedged into any drain pipe for that matter and cause an overflow situation.

A drain with an outlet that is open at the sump end does not have a worry for a (small) fish or anemone making it through - because it will make it through. The problem with a scrubber is that there is no large outlet - only a slot. So the fix is to not insert the screen all the way into the pipe. You need to suspend the screen from 2 points and make sure it only pokes up into the inside of the pipe a little bit. This will allow for room for anything that makes it's way all the way through to the slot pipe to get pushed freely to the end of the slot, leaving the water to pass through normally. This leaves you with the problem of how to get the buddy out of the end of the slot pipe, but leaves your tank not overflowing.

For a non-siphon system, you can employ the use of a bypass standpipe such as this one that I proposed a while back:

http://i611.photobucket.com/albums/t...cyoverflow.jpg

This type of arrangement, or something like it, allows for water pressure to build up over the slot, allowing the flow to keep under pressure and prevent algae from growing into the slot. But if the slot gets clogged, it backs up to the upper tee (right) and flows down a secondard outlet. The upper tee is near, but below the display tank water level, likely up the back of the tank. This does not work for a herbie / BeanAnimal full siphon line though as it breaks the siphon.

Personally if I were to run a scrubber off a full siphon line I would make 100% sure that the second line could handle the full flow in a non-siphon mode. Better yet, run a BeanAnimal 3-pipe system and you're really safe then.

A third drain is doable. I may well incorporate one as a further failsafe, in addition to using some sreen to block potential unwanted guests from even making it into the overflow to start with. Even then, I wouldn't be shoving the large amounts of water through it you sometimes see. It would only be enough to power the scrubber.

So beyond that, you think it should work out well enough?

http://www.beananimal.com/projects/s...ow-system.aspx

Full beananimal design won't work for me, since I am restricted to a corner overflow box. A slight modification with an added third drain, however, should work well enough. 2 of these extra drains should handle about 600 gph, which is more than what I'd be running through it.

Here is how I do it to avoid clogging/overflowing of the tank using an ATS fed via the overflow. Nice to see my 'mentor' over here. ;)

http://www.youtube.com/watch?v=AN7vsJ72Ero

Put a screen over your intake in the overflow box. Also, if you use the "no slot alternative" method for hanging the screen, there is less chance of getting a clog that backs up flow. The main reason I started using the "no slot alternative" is that growth would get in the slot and slow the flow. That wasn't really a problem, except that it threw off the balance of my 'herbie" drain set up and I would get too much water going through the emergency drain. I had no problems with the "no slot alternative".

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Originally Posted by Ace25

Here is how I do it to avoid clogging/overflowing of the tank using an ATS fed via the overflow. Nice to see my 'mentor' over here. ;)

http://www.youtube.com/watch?v=AN7vsJ72Ero

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Good to see you here, too. I can pick your brain, since you've now been using scrubbers longer than I have (and done much more with them, at that).

So in the video, you've basically set up a loop to bleed off any excess water? If so, that's the elegantly simple answer I was looking for.

I read the no slot alternative thread, but I'm trying to get a better grasp of what exactly it entails. Could either you or morgan elaborate on that, please?

The pipe for the screen/overflow on my setup is 1-1/2". At the end of the pipe I use a 1-1/2 to 1" reducer. Since it is a baffle in the sump I have a bulkhead on it, but that isn't needed. I then use 1" PVC, go up 6" and back down to the sump. When I hear gurgling coming from the pipe, I know my screen slot is clogged. It has worked perfect for me and I have zero concern about my overflow/ATS combo causing any issues. Having it go up 6" puts pressure on the slot as well which helps clean the slot some, and since it is well below the overflow box it still drains fine if the slot gets clogged.

I will let Morgan explain the no slot as that is his own idea that we have dubbed the 'MorganAtlanta method'. :)

So I've got a question. Looks like this is a new build but you're going with a waterfall design? I was under the impression that the newer upflow algae scrubber (UAS) types were now the way to go as they are cheap, easier to build, easier to incorporate into your flow, and just as effective. Are these all true assumptions? If so what are the benefits of going with this slot waterfall method over a UAS?

Should be easier to clean too if built right...

My opinion, those are false on ALL accounts. UAS are not cheaper, easier, and they don't work as well as the waterfall method. Waterfall method has years of testing/tweaking to make them work as well as they do, the UAS doesn't have that, and in turn it is my belief (from my own testing and others) that at this time they don't function nearly as well. That could change in the future with more people testing/fixing the issues with them but for today I wouldn't recommend one unless you want to experiment and work out the bugs.

That sounds like a bit of a dig at the UAS's so here's my 2 penneth in favour of the UAS bearing in mind I'm no expert, it's just my opinion...

Just the theory/science behind the UAS suggest to me that a well designed and well built one will perform better.

The UAS I am building at the moment suggests that it will be considerably cheaper than a waterfall.

The one I am building as far as I can see will also be a lot simpler in its operation (Screen Cleaning).

It will only take up a small amount of room in the sump as opposed to needing more external space.

Yes it is going to need testing, but I don't see any flaws in my design as yet.

Also...

Hasn't someone on here already started to feed bubbles into their waterfall scrubber, a downflow upflow scrubber :)

I think it may be Garf ?

Well, you see my video above. It is just a few pieces of PVC and a screen. 33 cents for the screen at my local fabric store and $2 worth of PVC parts, so less than $3 total. 2 small pieces of velcro to remove the screen to clean it.. couldn't be easier or cheaper.

http://www.youtube.com/watch?v=9wGllg25vvQ

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Originally Posted by Devs

Also...

Hasn't someone on here already started to feed bubbles into their waterfall scrubber, a downflow upflow scrubber :)

I think it may be Garf ?

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Guilty, as charged

Indeed... and very nice it is to...but...

A lot of people just want to buy things in boxes, take whatever it is out of the box, plug it in and along with a few guide lines/instructions voila !

Okay, after measuring the dimensions of my overflow box on my 40g, I won't be able to incorporate a 3rd hole. That shouldn't be a huge problem, because I'll be taking plenty of precautions as already mentioned on here. I'm pretty excited about this build and tank in general. It will also be the first tank I've had that has been "scrubbed" from day one. Will begin to document things in another thread as I make more progress. Things are moving slowly but surely right now. I'm trying to get all my ducks in a row before I really attempt to do anything.

I have no pictures since I deleted them. But I have always fed mine from my overflow. My last tank had a dual overflow in a single box like it sounds like yours is. So I used one and the other was an emergency overflow.

My current tank is a single overflow in a single box and I'm using a strainer to keep anything large from intering pipe. No emergency plan.

You wont be able to use a Herbie style on a overflow feed. Why? Because the pipe wont be under water in the sump as it need be creating the syphon effect. You can if you feed it from a seperate pump. I ran a Herbie when I used a skimmer. If it weren't for the skimmer that tank was dead silent. That's how I stumbled onto scrubbers. Turned off my skimmer one day and never wanted to plug it back in.

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Originally Posted by sklywag

I have no pictures since I deleted them. But I have always fed mine from my overflow. My last tank had a dual overflow in a single box like it sounds like yours is. So I used one and the other was an emergency overflow.

My current tank is a single overflow in a single box and I'm using a strainer to keep anything large from intering pipe. No emergency plan.

You wont be able to use a Herbie style on a overflow feed. Why? Because the pipe wont be under water in the sump as it need be creating the syphon effect. You can if you feed it from a seperate pump. I ran a Herbie when I used a skimmer. If it weren't for the skimmer that tank was dead silent. That's how I stumbled onto scrubbers. Turned off my skimmer one day and never wanted to plug it back in.

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The other end doesn't need to be under water to create a siphon (you wouldn't be able to do water changes with a plain vinyl hose if that were the case). In this case, it just needs to have some sort of resistance, like a ball valve. Once the overflow water level rises after applying back pressure, it will siphon just fine as long as the other end is lower than the drain.

Amphiprion, I understand what you're saying about the siphon principle, and while you are correct, there is a difference between a siphon hose to clean your tank (which is usually small diameter) and a siphon line for an overflow system (usually 1" ID). The larger the ID and the longer the vertical run, the more water that line is capable of flowing, and a line that is terminated under water at both ends has the maximum flow rate possible. The valve allows one to control the flow rate while keeping the line full of water. One of the principles behind the BeanAnimal or Herbie overflow systems is that you must terminate the siphon line under the water's surface (about 1/2" to 1") so that the line will purge all the air out in order to maintain the full siphon, which maximizes the flow through a pipe. One of the reasons for this is to remove the tendency for high-flow water crashing into the sump to create massive amounts of bubbles. Another is for versatility - if there were a change in water level (from sticking your hand in the tank, then removing it) the siphon line would have to restart. Without the line terminated below the water, the air my or may not ever purge out of the line, and you may not have a full siphon i.e. maximum designed flow. This happens, trust me. When I stick my arm down to the bottom of the tank, I can hear the open channel kick in, then if I remove my arm too fast, siphon sucks the box dry and has to restart. My system restart time is about 10 seconds from pump off to full siphon and balanced system, dead silent, no bubbles in the sump at 3000 GPH through a 1.5" drain.

If my system had the drain terminated above the water line, the water would fall out of the pipe and allow air into the line, causing a reduction in flow and much noise and bubbles. My ball valve on the line is a Cepex valve and is about 90% open

My design has since changed, but I ran my scrubber off a herbie drain for several months with no issues of not keeping a full siphon.

I think Floyd cleared my statement up pretty clearly. You may be running a Herbie standpipe as I am doing as well. Just a straight pipe. No elbows or other fittings. It too is submerged under the waterline in the overflow box to eliminate air and gurgling. But it is not running on a siphon. If your return pump is not sucking water through it, it is not on a siphon. And thus not a Herbie or BeanAnimal overflow.

The caveat to that is that with a slot pipe, the end of the outflow is essentially sealed in a similar fashion, because there is not a large open area for air to intrude upwards into. The slot pipe, conveniently enough, does not allow air up in the thin gap between the slot and the screen, or at least not enough to consider it breaking the siphon. At least, this seems to be the way it appears to work. So while it is not truly a tuned siphon in the Webster's definition (or Herbie definition), I believe the functionality remains

I'll have to experiment to see if I can replicate the same results I had before on my 75 with my particular design. It featured no standpipes, just bulkheads and fed directly to my skimmer (at the top of the skimmer). It functioned again immediately after shutting everything off (exposing the effluent to air), blasting out all the air that had made it into the tube and re-established a siphon automatically. It even functioned with the skimmer disconnected. The only thing that drove the water was the weight of a full overflow above the bulkhead and the resistance made by a ball valve below. Don't ask me why it worked, but it took a while to tune it and it functioned perfectly (and I was able to get much more than the usual 300 gph out of it, too).

Edit: If for some reason I cannot get the same results or get it to function properly, then I will likely resize the scrubber to fit the maximum flow rate the overflow can provide.

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Originally Posted by Amphiprion

... it took a while to tune it and it functioned perfectly (and I was able to get much more than the usual 300 gph out of it, too).

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Naturally

http://www.beananimal.com/articles/h...-aquarist.aspx

oh decisions decisions... UAS or WFAS... Guess either will be hard to incorporate into my system and keep it under the hood so to speak. If i went with the UAS it would fit easier but lighting it may be difficult especially from a two sided standpoint. A WF version i'm worried about salt creep and where to put it as i simply don't have a lot of space to work with. I really want to simply split my drain and run it off of a valve controlled line so that i don't have to run yet another pump. Just seems silly to me if it can be done without. i might end up just building a box to slide back behind my tank on the floor. then with either method it will be easy to access and clean ect.

You will have more salt creep with uas believe it or not.

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Originally Posted by RkyRickstr

You will have more salt creep with uas believe it or not.

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I fail to see how you came to that conclusion !

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Originally Posted by Devs

I fail to see how you came to that conclusion !

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BIG bubbles, BIG bursting bubbles, from a depth, erupting at the surface, equals lots of salt creep. Unless you prevent it somehow.

That I could actually see. I suppose if the water was flowing down the screen properly all the way to the water level in theory there should be little splashing. Just not sure how easy it will be to get it to do that.

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Originally Posted by Garf

BIG bubbles, BIG bursting bubbles, from a depth, erupting at the surface, equals lots of salt creep. Unless you prevent it somehow.

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Put a lid on it ! :)

I have never had any salt creep on any of my ATS's, but when I tried the UAS on the corner of a 10G frag tank not only was top corner covered in salt, but the entire side of the aquarium, wall behind the tank, and top of the stand was covered with salt creep in a day. Since the UAS is primarily designed for smaller/sumpless type setups putting a lid on the tank is the last thing I would want to do (trap gasses/lower gas exchange, in turn lowering both algae and coral growth). Also it blocks light from the tank when you put a lid on a tank to block salt creep as it just builds up on the inside of the lid reducing the light that gets through so you have to clean it daily. That is just for 'in tank' designs for saltwater, in a chamber in a sump that is different and could be done.

I contemplated a UAS, but I had already foreseen the potential salt creep issues. It also still seems like a bit of a work in progress and isn't as perfected as the waterfall scrubbers just yet. I've had incredible results in the past with waterfall-style setups, so that's why I'm pursuing that design.

Oh dear...

I don't mean a lid on the tank ...look at the image i posted on here of my design, infact...I'll post it again here...I've shown the lid in clear acrylic just to distinguish it from the rest of the casing...

Attachment 3837

Also...

Where on earth do you get the idea from that UAS's are for smaller/sumpless setups ???

The design in my previous post is a 2 cube UAS...it is only 136mm wide, which enables it to fit in those narrow sump sections. The base is split in half and both halves angled up to finish just 1.5 to 2mm short of the bubble bar, this in effect will creates a bubble catcher which would capture bubbles given off by the drain coming into the sump, therefore possibly being able to eliminate the use of an air pump.

so...two of these would give you 4 cube feeding per day giving an overlap on the cleaning. IMO More than 6 cube feeding per day I would consider as a custom build anyway.