building my first custom sump/refugium

[KENthereefnoob]

Looks good! Simple and useable. Do you have any more pictures of your sock holder?

Here are a few pics I took this morning of the sock holder, thanks -KEN

 

[smedlin]

Looks really nice Ken. Really nice.

I'm getting ready to do a similar project with same 29g tank.

 

[dotkat77]

I would not do filter sock holder this high in case it clogs. It will not overflow the sump just back in to the sump.

 

[mmittlesteadt]

Acrylic does absorb water and expand. If the baffles are tight enough and they expand...well, there goes the glass.

And silicone does not fully adhere to acrylic. Enough silicone on either side of the acrylic will hold it in place though.

 

[KENthereefnoob]

Thanks guys. That's a good call on the filter sock being too high, but if it were to get clogged to the point where it would overflow, wouldn't that mean that the entire sock and the entire lining of it would need to get clogged for it to overflow? Has anyone ever scene a filter sock clog and overflow? If it is a common thing, or even possible, maybe I can build some retaining walls to divert the water back into the sump and not over the edge. Thanks again for all your thoughts fellas.

 

[KENthereefnoob]

Each baffle had 1/8" clearance of the glass. It was filled w dap silicone. I used a lot. It took 3 tubes to seal the baffles so I'm confident in its construction.

 

[KENthereefnoob]

Acrylic does absorb water and expand. If the baffles are tight enough and they expand...well, there goes the glass.

And silicone does not fully adhere to acrylic. Enough silicone on either side of the acrylic will hold it in place though.

pulled this article from the NIH, it is a formal study on the absorption of water in acrylic.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2635902/

in a study of 30 20mm x 20mm acrylic squares, the absorption of water was at 11.33±0.33 to 30.46±0.55 μg/mm3. so there is absorption, but very minimal, and most likely not enough to bust glass panels through expansion.

 

[sleepydoc]

just do yourself a favor and do a little research here...i swear i've read a bunch of threads that say if you put acrylic baffles in a glass sump they'll eventually absorb enough water to swell and crack the glass

It seems to be a pretty common thing, putting acrylic baffles in glass sumps.

What your probably thinking, I have read that you don't want the baffles to be so "tight" it pushes (hard) against the glass sides....

Not sure why using silicone to seal acrylic to glass would absorb water and shatter the tank, the sump will go into a testing phase in my garage for a few days after it fully cures so I cam check for leaks or failures before it goes into service.

When immersed acrylic will absorb water and expand slightly. The numbers I've read on data sheets say up to 6%, which would be about ⅝" per foot, depending on the type of acrylic used. IME it's significantly less than that, but it still occurs. If you have a tight baffle with no extra room, it can put stress on the walls of the sump and can lead to failure (there are many reports of this, so it's not just a theoretical concern.)

The other issue with acrylic is that silicone will not adhere to it long term. (do a search on my name, silicone and acrylic and you should find some examples.) You can use silicone to secure baffles in place in a glass sump because the silicone adheres well to the glass and essentially wedges the baffle in place between the two fillets.

• My general advice for glass sumps is:
• Glass baffles are best and generally cheaper
• If you use acrylic, allow ⅛ ~ ¼" for the baffle to expand to avoid stress on the sump.
• Never use them where a water tight seal is critical or where you need the silicone to keep the acrylic from pulling away

There are many people who have used acrylic baffles in sumps without issue (myself included,) you just need to be aware of the limitations and risks and account for them in your design..

 

[sleepydoc]

Thanks guys. That's a good call on the filter sock being too high, but if it were to get clogged to the point where it would overflow, wouldn't that mean that the entire sock and the entire lining of it would need to get clogged for it to overflow? Has anyone ever scene a filter sock clog and overflow? If it is a common thing, or even possible, maybe I can build some retaining walls to divert the water back into the sump and not over the edge. Thanks again for all your thoughts fellas.

Yes, I have personally seen socks clog enough to overflow, so I would definitely move the sock down.

As I and others have mentioned, silicone won't hold acrylic well and the holder may very will pull off the wall at some point.

Other questions/potential concerns with the design:
- Make sure you have enough headroom in your stand to raise you skimmer up if necessary. As you said, you can always build a riser for your skimmer if necessary, but you are limited by headroom.

- How are going to have water flowing into the filter sock? if you are using a silent overflow, the pipe needs to be submerged, meaning it will extend down into the sock. If you do this, you won't be able to remove the sock. If you have the pipe outlet above the sock, you will get a lot of splashing. You could potentially tee off the return or have a separate pump pumping water through the filter sock, but that significantly reduces the filtering efficiency.

- Make sure you have enough extra capacity in your sump to hold water that siphons down in case of a power outage. The high baffles in the first section take up some extra volume; whether it's an issue or not depends on the rest of your plumbing.

- the first section seems quite narrow. I assume your current skimmer fits there; if you're ever considering upgrading skimmers, you might look at a few and check their footprints so you don't have to move the baffles later.

 

[KENthereefnoob]

@sleepydoc i will be using a flexible ribbed hose and it will be placed down the sock below the waterline to prevent splashing and trickle noise. it will be secured by a clip i made that will hold the hose down. probably not even needed but for piece of mind.

i also did some calculations to determine how much water my overflow would spill into the custom sump during a power outage, or if i cut power to perform maintenance. it is well under what the sump will fill to in the event that i turn the power off. i dont have those figures on hand (im at work at the moment), but i will post them later tonight.

the first section does look narrow in the pictures, but i believe i made it 7" before the first baffle and the width of the tank is 12" so i have a 7 x 12" area in the first compartment. i think i can find a number of skimmers that will accomodate that area.

the sump is currently filled with water and i am running a leak/failure test on it. i will give it a few days before i place it into operation.

i think instead of lowering the sock holder, i will build a gutter that would deflect water into the tank in the event of an overflow. if i lower the sock holder, it will put it below the water line of the first compartment, which would wllow water to flow in and out of the top of the top of the sock.

please think of anything else that might seem wrong or could cause problems in my design as i am trying to proof this thing as much as i can before i put it into service.

thanks everybody!