Sump Design - 20 Gallon Long

[dsinsocal]

I'm in the process of upgrading from a 29g to a 90g so I'm making plans and gathering all of the necessary equipment. I realized that the biggest sump that will fit under the stand is a 20 gallon long. Larger tanks would either be too wide to fit, or too tall to access for maintenance.

One serious option is to just build a new stand from scratch, making it a bit larger overall and adding a side door for easier access. However, while I'm certainly skilled enough to build it, I'm not skilled enough to make it look like a legit piece of finished furniture. Since this is located in my home office, that's a pretty important issue, so I'm not sure I want to go that route without seeing if I can't squeeze enough mileage out of the 20 gallon first.

I currently only run a 5.5 gallon HOB AquaFuge right now (about 20% of DT volume) and everything runs great, so maybe a 20 gallon would be up to the task if designed properly. I'm looking for some expert advice on the attached layout from people who are a lot smarter about this stuff than I am. This doesn't come naturally to me, so factoring in flow rates and patterns, backflow capacity, water levels -- both constant and variable, etc starts to make my head hurt after a while.

I plan to run a 3-drain bean animal setup. The primary and secondary draining into the first chamber and the emergency hovering over the refugium chamber for maximum noise in the unlikely event of a clog.

The first chamber will house a Bubble Magus Curve 5 skimmer with a footprint just a shade over 7 x 7. I will elbow off the drain pipes at 45 degrees toward the skimmer and should have enough room on that side of the chamber for a block of Marine Pure. (as we go along you will find that Marine Pure is one of my favorite reef products ever!)

This chamber will transition through an adjustable spillway -- 6" to 9" range. Some people have reported needing 10" to run the Curve 5, but most people seem to run them in the 7" to 9" range with great results. That spillway will drain down on two removable shelves. Shelf #1 will contain mechanical filtration in the form of filter floss. Shelf#2 will contain a 6" bag of carbon, and a 6" bag of Chemipure Blue. The chamber beneath the shelf will contain more Marine Pure, cut to fit.

That will drain into the bottom of the main refugium chamber which will have a removable/adjustable divider. You can run it as one large chamber if you want, or divide the two halves as your specific needs arise. For me, I plan to lay a 1" layer of Marine Pure in the back half (hence, the inlet holes being 1.25" off the floor) and devoting the rest of that chamber to a tumbling ball of chaeto.

A question for people with more exerience: will that design create enough of a circular flow to tumble the chaeto? If not, what if I installed a ramp on the opposite wall to direct the flow upward? Will the cross flow exiting that chamber through the divider disrupt things? I want that chaeto to tumble but I'm not sure my design will achieve that.

The front chamber is an open concept right now. I'm not sure if I want to go with rubble rock (so I always have cured/colored pieces on hand), containers of mud, or maybe just some frag racks. Regardless, Marine Pure will definitely be cut to size and fill in anywhere there is open space for it.

I purposely wanted that front chamber to run at least 19" so I could fit a full 200w heater in there. I haven't seen a pre-cut kit for a 20 gallon that was capable of submerging a 200w heater, so that was an absolute requirement.

Finally, the last chamber is the return pump, partitioned off just so large items didn't find their way into the pump. The chamber is 7.75 x 5. The pump I'm using is a Quiet One 2200 that pushes about 400 gph at 4ft. The dimensions of the pump are about 4.5 x 6.5, so I think I left plenty of space in that chamber as to not see any problems.

I'll be running a water level between 8-9 inches in the skimmer section, and between 7-8 inches for the rest of the sump. Back-flow into the sump is a major concern here, as there isn't much space to accommodate gravity drainage when the power is cut -- especially if I'm using a bulkhead return, which is the strong preference here.

As much as I hate to consider it, I might have to think about an over-the-back return. I'm assuming that lock-line cannot be considered "water tight" and that the tank will still drain down to the bottom of the bulkhead even if the lock-line is tilted up to the surface of the water?

I'm eager for critiques and ideas. Thanks all.

 

[Evan West]

Do you have a method to regulate the water levels in the chambers past the first chamber? With the holes like you have not there is no apparent way to control the water levels in these chambers and this may be useful.

 

[dsinsocal]

Do you have a method to regulate the water levels in the chambers past the first chamber? With the holes like you have not there is no apparent way to control the water levels in these chambers and this may be useful.

I don't, as I didn't feel it was necessary to do so. I put the skimmer chamber first, because that's the only one that was level-critical. I didn't foresee a need, or desire, to maintain differing levels in the other chambers. As long as there is enough water to cover the shelves in the spillway chamber everything else should function properly. I will be keeping them relatively low (likely between 7 and 8 inches) in order to have enough room in the sump for backflow.

That center divider is designed to be adjustable/removable and is really only there to keep the chaeto penned up in it's own area so it doesn't end up stuck in the corner near the return pump. If the ball of chaeto gets big enough, that divider can be removed and that chamber would be used as a single, large refugium. The only other chambers would be the return pump and the spillway, and I didn't see a need to maintain special water levels in either of those.

But this is exactly why I posted here, because I could very well be overlooking something. This is certainly not what I would call "within my expertise".

 

[GK3]

Where is your return pump going?

 

[dsinsocal]

Where is your return pump going?

Finally, the last chamber is the return pump, partitioned off just so large items didn't find their way into the pump. The chamber is 7.75 x 5. The pump I'm using is a Quiet One 2200 that pushes about 400 gph at 4ft. The dimensions of the pump are about 4.5 x 6.5, so I think I left plenty of space in that chamber as to not see any problems.

 

[GK3]

So with the holes you have drilled for water flow into that section, it will create large salinity swings. You want your pump section to be as small as you can and have water flow over the top of the baffle and fall down. Then your ATO can sense when the pump area is getting low and fill it up. The way you have it, with the holes, that entire area after the media rack will have to lower before your ATO detects it and tops it off. It just causes a larger salinity change then necessary. I suggest taking the holes out.

 

[dsinsocal]

So with the holes you have drilled for water flow into that section, it will create large salinity swings. You want your pump section to be as small as you can and have water flow over the top of the baffle and fall down. Then your ATO can sense when the pump area is getting low and fill it up. The way you have it, with the holes, that entire area after the media rack will have to lower before your ATO detects it and tops it off. It just causes a larger salinity change then necessary. I suggest taking the holes out.

I originally designed it exactly how you described, for exactly the reason you described (smaller, more frequent top-offs), but changed my mind for a few reasons (both of which may be completely flawed).

1. I thought water falling over the baffle might create bubbles that would be immediately transported into the display.
2. I thought water falling over the baffle might create unnecessary noise.
3. I considered it "unnecessary" noise because I rationalized that the potential salinity swings would be irrelevant.

My current display is 29 gallon, with no sump. My ATO sensor is inside the display tank, so my system probably sees about a gallon of evaporation before the ATO actually kicks on -- which is 4% of total volume. The ATO in this sump would probably kick on after about .75 gallons, plus we're talking about 3 times the water volume, going from 35 to 105 gallons of total water, so I didn't think the salinity would be an issue.

I've never noticed any significant salinity swings, but this begs the question of what "significant" means. Is swinging from 1.024 to 1.0245 considered significant? Given that reef dwellers thrive on consistency, perhaps it's a bigger deal than I give it consideration for.

I've never had a sump before. How much noise would result in just letting the water fall over a baffle a couple of inches? Is there a significant splash/turbulence? Would bubbles being created by the splash be a problem? The clean, quiet flow of the 1/4" partition holes just seemed like a better option at the time. I'm open to changing it though if people feel that it would be best for the health of the tank.

Thanks for the feedback!

 

[GK3]

I originally designed it exactly how you described, for exactly the reason you described (smaller, more frequent top-offs), but changed my mind for a few reasons (both of which may be completely flawed).

1. I thought water falling over the baffle might create bubbles that would be immediately transported into the display.
2. I thought water falling over the baffle might create unnecessary noise.
3. I considered it "unnecessary" noise because I rationalized that the potential salinity swings would be irrelevant.

My current display is 29 gallon, with no sump. My ATO sensor is inside the display tank, so my system probably sees about a gallon of evaporation before the ATO actually kicks on -- which is 4% of total volume. The ATO in this sump would probably kick on after about .75 gallons, plus we're talking about 3 times the water volume, going from 35 to 105 gallons of total water, so I didn't think the salinity would be an issue.

I've never noticed any significant salinity swings, but this begs the question of what "significant" means. Is swinging from 1.024 to 1.0245 considered significant? Given that reef dwellers thrive on consistency, perhaps it's a bigger deal than I give it consideration for.

I've never had a sump before. How much noise would result in just letting the water fall over a baffle a couple of inches? Is there a significant splash/turbulence? Would bubbles being created by the splash be a problem? The clean, quiet flow of the 1/4" partition holes just seemed like a better option at the time. I'm open to changing it though if people feel that it would be best for the health of the tank.

Thanks for the feedback!

1. It will not unless you are going from a 18” baffle falling into 4” of water. Simply having 1-2” of height difference won’t.

2. Same as above. You are creating a waterfall so keep it short and it won’t be an issue.

3. For me I find any salinity swing relevant. I try to keep mine as stable as possible. 1 gallon from 29 is a ton in my opinion. I’d go for have my ATO do smaller water more often then a ton of water less often. Your fish will throw you a high five.

Do you have a salinity prob or just occasionally checking?

 

[dsinsocal]

I check it a few times a week, often times before and after a top-off, or before and after a water change. I plan to use a probe in this system though.

In retrospect, you're totally right about the salinity. I bust my butt to keep Calc, Alk and Mag consistent so why wouldn't I strive to do the same for something vital as salinity?

That said, I just remembered the main reason why I ultimately opted against doing it that way.... 20 gallons is a small sump and the only way to safeguard against overflow is to keep the water level low. I wouldn't be able to make that baffle more than 8 inches max -- and might even need to go a little lower than that to ensure that I have enough room, depending on how I situate the return nozzle.

Not knowing exactly how much of a "drop" would result on the other side of the baffle, I feared that I might not be able to leave enough water depth to accommodate the process. If it starts at 8, cascades to 6 and then evaporates to 5, I fear that the pump might start sucking air. I really wish a 40g would fit under that stand. It would solve a lot of problems.

 

[GK3]

Are you worried about the sump overflowing on a 90g or 29g?

Also- your salinity swing on that 29g is probably pretty high you just aren’t seeing it because of when you are checking.

 

[dsinsocal]

The sump is being built for the new 90g. I just have a HOB Aquafuge on the 29g.

I test salinity with a refractometer, meaning the readings are dependent on the eye. The line is always somewhere between 1.024 and 1.025 hashmarks, so I don't notice any obvious swings.

 

[GK3]

The sump is being built for the new 90g. I just have a HOB Aquafuge on the 29g.

I test salinity with a refractometer, meaning the readings are dependent on the eye. The line is always somewhere between 1.024 and 1.025 hashmarks, so I don't notice any obvious swings.

I meant you don’t notice because you mentioned you usually test after a top off. I’d expect that to always be the same. I like the probe just because I always know. There have been a few times I’ve noticed high salinity and realized my ATO wasn’t working.

I have a 20L as a sump and I think most of my baffles are at 9”. All you have to do is make sure the back siphon on the return can’t overflow it. If it does, move the return nozzle up. I used to use 8” baffles in my 20L and rebuilt the whole thing because I felt that I could get more water volume out of it, which I did.

 

[dsinsocal]

I check it a few times a week, often times before and after a top-off, or before and after a water change.

Now that I'll have a sump when the 90g gets set up I'll have room for probes and I'll be able to track this stuff more closely. While it's certainly ideal to have a 100% stable salinity reading, I'm not super worried about the variance now that I'll have 3 times the water volume to dilute it with.

If I was dealing with my 29g I wouldn't worry about the back siphon, but the 90g is going to back siphon considerably more than the 29g does. I've never had a drilled tank before, so I'm not sure if I have to plan for the water to drain all the way to the bottom of the bulkhead, or if I can cheat the system by angling my loc-line up near the surface. As of right now, I'm assuming I'll have to plan for a 2-3" drop during back siphon.