Jump to content

Overflow Design questions

Recommended Posts

So the bottom of the tank I am refurbishing is drilled so the overflow and return come up through the bottom allowing for a more flush fit to the wall.

It had an Aquoen Overflow kit with the large back piece.

What can I do to be able to put this back together with out the large black piece.  What is the name of the large black piece?  I'm such a newb!

There is a article by CO-OP that outlines using filter media, polyester yarn and plants to build your own back ground , which is what I wnat to do.  I will paint the piping to blend into the planting.  Then plant tall growing plants round them.  Which I would like better then large black towers.

So, question is. How can I get that done?  Hopefully with out a ton of noise.  

OH, it is going to flow into a seamless Sump system underneath.



Link to comment
Share on other sites

  • Administrators

The part you removed is the overflow box. This helps set the height of the water level in the aquarium and was a first line of defense for debris/fish not getting sucked up against in intake screen.

In my opinion you'd be best to have 2 down flow overflow pipes. One setup as a siphon, and the second setup as a backup. This is known as a herbie drain system, normally uses 3 pipes. Then your return line would come from over the top of the back wall of the aquarium.


Once you have this process working well, covering it up in your aquarium can be done a few different ways. Usually you'll want to either use black pvc and a black background in the tank, or wrap them with something as the wipe pipe will stand out no matter what you do.

You'll need to do a lot of research to learn quite a bit about overflows as this is a subject that is pretty difficult to teach not in person and with some more hands on experience.

Link to comment
Share on other sites

The black thing is called an overflow. Even though it's on the inside. When I make 3D backgrounds I prefer to keep it to hide the plumbing and build the background around it. For a background I prefer using styrofoam to cut out the shapes and silicone to attach everything together. For emersed plants I like to buy HOB planters and incorporate it into the styrofoam background. Using a hobby knife and a soldering iron you can cut details into the styrofoam. After you're done use an aquarium safe sealer, like drylok and some masonry dye to get the rock or dirt hues correct.


Like Cory said without experience doing a lot of research and may take a few attempts with the plumbing to get it  right. 


All of this is to not dissuade you it is very rewarding to have an aquarium in the home that is of show quality and your fish and animals will reward you with natural behaviour.

Link to comment
Share on other sites

The tank has a total of 4 holes in the bottom.  2 for out, 2 for return.  So I think I will devise a strainer on top with straight pipe going down.  I have a straight pipe with a nozzle for the returns.  I will use valves to adjust flows and allow shut off for maintenance.   I think this will work??  Thoughts?  The sump will have two socks so mabey have one drain into each sock?

Link to comment
Share on other sites

That sounds good. Control valves are a must with a sump and you will want to establish a min/max fill in your overflow as well. Having socks to catch debris is great but make sure to have other media in the sump. Filter floss and whatever brand of bio-balls work good. Same with ceramic rings.


Without actually being there like Cory said it's hard to help plan it out so I apologize for leaving things vague.

Link to comment
Share on other sites

Yes, that looks like a decent enough guide. 

As folks have said, keep the overflow in.  If you want you can cover that with your background material to hide it.

Looks like you have a Durso in there right now.  I concur with Cory.  Make it a Herbie. 

The big thing to keep in mind is that you'll need a "gate valve" on the main drain line.  I see your guide mentions them, but like many it also suggests the possibility of using a "ball valve".  A gate valve give you far more fine level control, and that makes all the difference in the world for matching the flow rate going through the line and keeping the flow quiet.

With a gate valve, suddenly the project has much bigger error bars around the flow rate.  Then remember to leave the emergency line open, i.e. no valves to allow free flow.  After that it's just a matter of height to volume conversions to figure out capacity (the sump must have a enough room when operating to accommodate the outflow from the tank until to drains when the pump goes off).  Ideally, you have your pump and sump set so that if the drains both somehow clog the sump can't overflow the tank either.  That's a lesser concern, but one I aim for.

If you have questions, keep posting here.  It looks like it is going to be a fun build! 

Link to comment
Share on other sites

To figure out the maximum amount of water you might need to be able to store in the sump, measure the height of the aquarium and then divide the total gallons (150 in your case) by the height to get an estimate of the number of gallons per inch of height (estimate because some manufacturers have some error bars around the gallons they report for any given tank size). 

Then because your overflow has holes in the middle and bottom (was that a correct assessment from the photo?), you'll have to decide how high you want your main drain line to be.  It will need to be lower then the bottom of the top holes, and then a little bit so it doesn't suck in air.  But remember that when you turn off our pump your tank will drain to that level.  So if you make it too low, you'll end up with more water draining then your sump can accommodate.  I'd suggest, given that you know how much space you have in your sump (I build my own so I have other calculations to do), figure out how far down the maximum depth of the overflow can be from the lip, and then don't exceed that.  That should keep you in the safe zone.

The returns are through the bottom?  That's another thing to think about, especially if you are going with the H2Overflows.  Once you are comfortable with the drain line plans, then start to think about the return lines.  The big thing there is just to make sure you don't have the returns set too deep, or have a siphon break built in.

Sumps really aren't too complicated, though I do wish some company would just sell tank/stand/sump sets.  That would get more people interested in them. 

  • Like 2
Link to comment
Share on other sites

I am thinking with the H2Overflows pictured above I can straight pipe down into the socks.  One pipe per hole , one pipe per sock.   There will be the gate valves for the overflows and returns for fine tuning.   In most videos or web reviews I am seeing they pipe this out the back and down into the sump the only difference is I am going through the tanks bottom.  and a straight pipe up going to the return pipes.   Super simple.  Well

Link to comment
Share on other sites

On 8/2/2021 at 8:21 AM, ThomasLC said:

One pipe per hole , one pipe per sock.   There will be the gate valves for the overflows and returns for fine tuning. 

I like it!  That seems like a good plan and design for the drain lines.  You do not need, nor do you want, valves on the return from the pump.  Closing valves down on return lines creates back-pressure on the pump which will shorten the lifespan of the pump. 

Will you be using two pumps to feed the returns?  Or a single pump with either multiple outlets or a plumbing splitter?  The advantage of using two pumps is the redundancy in case one goes out.  The disadvantage is typically this results in greater power consumption and heat input into the water (this heat can be good or bad depending on your situation and season). 


  • Like 1
Link to comment
Share on other sites

150 gallon tank divided by the height of 28" tall give me 5.35 gallons per inch so I can go 3 inches of water return before I get close to using up the 20 gallons of reserve space.

Side note.  Even though the tanks full capacity is 150 gallons one rarely uses the full capacity.    3" of sub straight uses 16 gallons, then a good 1/2 inch uses another 3 gallons mins decorations equipment and plants , a 150 gallon tank you really get about 120 gallons of water.  The Sump operates at 55 gallons, but you have to take out take the volume of media, and equipment again.  So 55 gallons is more like 35.  

So in short my 150 gallon aquarium with a 55 gallon sump isn't a 205 gallon system but more of a 155 gallon system.  I just have to keep that in mind when stocking it.  I got such a large sump system so I could overstock the tank a bit. 

Link to comment
Share on other sites

So I am replacing the upper brace.  I took it off during the reseal project and have the new one ready to go on.  Question is:

Do I put the new one on before I leak test?  I mean its there to provide support with all that water in it.  But at the same time, it the tank leaks I will have to order a new one as it would be impossible to remove the top of the sealant with that in place?

Link to comment
Share on other sites

On 8/3/2021 at 8:18 PM, Cory said:

In the drawing above. You'll only want to use 1 valve to control the 1 siphon drain. The other drain needs to be fully open or at some point you'll likely have a flood from crud buildup.

Excellent catch, sir! 

Yes, Cory is absolutely correct.  I was remembering the photo above with the bottom holes and that I'd mentioned before:

On 7/31/2021 at 8:10 AM, OnlyGenusCaps said:

Then remember to leave the emergency line open, i.e. no valves to allow free flow.

I failed to see that the returns took the place of the emergency drains in the diagram.

With four holes in the bottom, I'd be apt to have a main/gated drain line and an emergency/ungated drain behind the overflow boxes.  Then place the returns over the top from the back or the sides if you want it flush to the wall.  I tend not to like having the returns come up through the base anyhow.  Having the returns further from the overflows allows me to configure in ways I think I get better circulation and that reduce dead spots in the tank. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...