Converting Spare Aquarium into Sump or Refugium?

[Vaesive]

Hi all!

So I recently decided to get back into fish keeping and picked up a 40g breeder aquarium. I have simple experience in freshwater (30g tank I had for a few years which is the spare in question) and also had a nano 5g saltwater reef aquarium at my office. I've never had a sump or refugium (tbh, I'm a litle hazy on what the major differences are).

What I'd like to know is how I could possibly use my old 30g as a "addition" to my new 40g freshwater. I'd prefer to use the cannister filter I have for filtering purposes (converting it for filtration would be a pain since it's a bowfront) but was thinking having an extra 30g available would be nice for a few reasons:

• Water changes would be simpler and wouldn't disturb the display tank.
• More water volume is a plus for stocking as well as catching/minimizing water param fluctuations.
• Adding medications, supplements, etc. is a little less "shocking" to the system.
• I'd love to grow more plants in the "refugium" as well as possibly use it for fry if my fish happen to spawn.

Basically, I'm wondering how I could go about achieving this, if at all possible, and I'd like to avoid modifying the main tank (ie drilling holes in the glass).

Any advice or tips would be greatly appreciated and thank you in advance!

 

[Andy Sager]

Can it be done? Yes. There are a number of options. That said however, not all of them work without flaws. ( Open Siphon based designs will work until the power goes out. If the siphon is broken, you are looking at a flood when the power goes back on. :^0 ) If you want to add the 30 as a filtering sump which will add 30 gals ( a little less actually) of water to the system, that's one design. If you want to add the 30 as an add on to the system for the plants and fry, that should be a different design since you don't want the water flow as high through a fry tank as you would the main tank.
So the first question ( of many ) is where is this "sump" going to be located in reference to the main tank?
Are you able to drill the 30 gal for a sump pump or are you looking for an internal pump that will sit inside the tank?
Are you able to use an overflow box on the back ( or side) of the breeder tank?
We can go from there.

 

[Vaesive]

Thanks for the reply; I really do appeciate it!

• The 30g would go under my main tank in the display stand (like a normal sump would be).
• I don't mind drilling the 30g so that could be an option although I'd prefer not to (mostly because I wouldn't want to comporomise its structural integrity due to fault of my own). If internal pumps are possible I'd probably go with that.
• I will not be using an overflow box.

Throw out the fry idea if that would cause any discrepencies; it was just an off-the-cuff thought. I would like to use it as a place to grow plants though

 

[Andy Sager]

Thanks for the reply; I really do appeciate it!

• The 30g would go under my main tank in the display stand (like a normal sump would be).
• I don't mind drilling the 30g so that could be an option although I'd prefer not to (mostly because I wouldn't want to comporomise its structural integrity due to fault of my own). If internal pumps are possible I'd probably go with that.
• I will not be using an overflow box.

Throw out the fry idea if that would cause any discrepencies; it was just an off-the-cuff thought. I would like to use it as a place to grow plants though

Okay, there are submersible sump pumps so you will need to look into those. The key item you are looking for is flow rate at head ( how much water flows at what height) so you get one that can handle the height you will require.

Since you want to use it for plants which will mean adding substrate ( I presume) you should glue in a glass divider in the sump if the tank is a glass tank ( over plexiglass since it can bend) so that your pump can be protected from the substrate. If the tank is plexi, use plexiglass glue to secure the divider.

The big issue is getting the water from the top tank to the bottom one. In looking for some examples online to show you how it would look, I found mostly ones using a siphon tube from the top tank to the bottom if the top tank wasn't drilled. This is by far the most dangerous method since the siphon will break if the electric goes off and if you are not at home to restart it when the electric comes back on, you are looking at a flood in your house or if you put the tube low enough in the upper tank to prevent accidental breakage of the siphon, the bottom tank will flood from the water in the top tank. This is why it's recommended to use an overflow box since they are designed not to break the siphon if there is no electric. You will need to install check valves into both lines to prevent a reverse flow but they tend to reduce flow rate so you will need to compensate for that when choosing pumps and piping.

The next part is what type of filtering will you have? You can either filter the top tank or the bottom since they will be connected so all the water will be getting filtered. In many sumps, a section can be dedicated to filtering materials removing the necessity for other filtering models. This is a link to a page of multiple designs for sumps ( for sale) so you can see what you are getting into. https://www.tthme.com/?category_id=6896265 ( All of these can be DIY. I've built many )

Check these out and we can go from there.

 

[Vaesive]

Okay, there are submersible sump pumps so you will need to look into those. The key item you are looking for is flow rate at head ( how much water flows at what height) so you get one that can handle the height you will require.

Since you want to use it for plants which will mean adding substrate ( I presume) you should glue in a glass divider in the sump if the tank is a glass tank ( over plexiglass since it can bend) so that your pump can be protected from the substrate. If the tank is plexi, use plexiglass glue to secure the divider.

The big issue is getting the water from the top tank to the bottom one. In looking for some examples online to show you how it would look, I found mostly ones using a siphon tube from the top tank to the bottom if the top tank wasn't drilled. This is by far the most dangerous method since the siphon will break if the electric goes off and if you are not at home to restart it when the electric comes back on, you are looking at a flood in your house or if you put the tube low enough in the upper tank to prevent accidental breakage of the siphon, the bottom tank will flood from the water in the top tank. This is why it's recommended to use an overflow box since they are designed not to break the siphon if there is no electric. You will need to install check valves into both lines to prevent a reverse flow but they tend to reduce flow rate so you will need to compensate for that when choosing pumps and piping.

The next part is what type of filtering will you have? You can either filter the top tank or the bottom since they will be connected so all the water will be getting filtered. In many sumps, a section can be dedicated to filtering materials removing the necessity for other filtering models. This is a link to a page of multiple designs for sumps ( for sale) so you can see what you are getting into. https://www.tthme.com/?category_id=6896265 ( All of these can be DIY. I've built many )

Check these out and we can go from there.

Thank you so much for the info! I'll have to do some thinking because the siphon idea does not sound ideal. I don't think power has gone out in my house once in the 10 years I've been year but I really wouldn't want to chance a flood...

I didn't know overflow boxes were so simple or easy. Could I use something like this to accomplish what I need?

 

[Vaesive]

This is a link to a page of multiple designs for sumps ( for sale) so you can see what you are getting into. https://www.tthme.com/?category_id=6896265 ( All of these can be DIY. I've built many )

Check these out and we can go from there.

Is this the correct link? It takes me to a shoe store.

 

[Vaesive]

Okay, there are submersible sump pumps so you will need to look into those. The key item you are looking for is flow rate at head ( how much water flows at what height) so you get one that can handle the height you will require.

Since you want to use it for plants which will mean adding substrate ( I presume) you should glue in a glass divider in the sump if the tank is a glass tank ( over plexiglass since it can bend) so that your pump can be protected from the substrate. If the tank is plexi, use plexiglass glue to secure the divider.

The big issue is getting the water from the top tank to the bottom one. In looking for some examples online to show you how it would look, I found mostly ones using a siphon tube from the top tank to the bottom if the top tank wasn't drilled. This is by far the most dangerous method since the siphon will break if the electric goes off and if you are not at home to restart it when the electric comes back on, you are looking at a flood in your house or if you put the tube low enough in the upper tank to prevent accidental breakage of the siphon, the bottom tank will flood from the water in the top tank. This is why it's recommended to use an overflow box since they are designed not to break the siphon if there is no electric. You will need to install check valves into both lines to prevent a reverse flow but they tend to reduce flow rate so you will need to compensate for that when choosing pumps and piping.

The next part is what type of filtering will you have? You can either filter the top tank or the bottom since they will be connected so all the water will be getting filtered. In many sumps, a section can be dedicated to filtering materials removing the necessity for other filtering models. This is a link to a page of multiple designs for sumps ( for sale) so you can see what you are getting into. https://www.tthme.com/?category_id=6896265 ( All of these can be DIY. I've built many )

Check these out and we can go from there.

Hmmmm, I may have to do some thinking then. I'd rather not do the siphon route even though I don't think I've lost power in the 10 years I've been at my house but I also don't want to chance a flood...

I did some looking and didn't realize overflows were so simple or readily available? Like, would THIS work for what I need? Or am I missunderstanding something.

I'd probably use my canister filter to filter the sump tank out on it's way to the display tank? This wouldn't remove or dilute any medications or supplements added to the sump, would it? I'd preferably like to add it to the "in" of the sump but would worry that the unfiltered sump water going back into the display would be a bad idea.

 

[Andy Sager]

Is this the correct link? It takes me to a shoe store.

Try this one: https://www.tthme.com/?category_id=6896265 When I click on it, it goes to where I sent you. It's a site that sells many things ( including sneakers) but I use it to show the different styles that can be built. The top of the page should show " 10 gallon freshwater sump design" and the bottom of the page should have Hygiene products.

 

[Andy Sager]

Thank you so much for the info! I'll have to do some thinking because the siphon idea does not sound ideal. I don't think power has gone out in my house once in the 10 years I've been year but I really wouldn't want to chance a flood...

I didn't know overflow boxes were so simple or easy. Could I use something like this to accomplish what I need?

You need to match the overflow box to the pump you are using. A pump that flows faster than the box can drain is not going to end up well either. So don't rush out and buy one until you have the other equipment to match it up. This is an article from a marine supply site but the information in the article applies to any system: https://www.bulkreefsupply.com/choosing-an-aquarium-overflow

 

[Andy Sager]

Hmmmm, I may have to do some thinking then. I'd rather not do the siphon route even though I don't think I've lost power in the 10 years I've been at my house but I also don't want to chance a flood...

I did some looking and didn't realize overflows were so simple or readily available? Like, would THIS work for what I need? Or am I missunderstanding something.

I'd probably use my canister filter to filter the sump tank out on it's way to the display tank? This wouldn't remove or dilute any medications or supplements added to the sump, would it? I'd preferably like to add it to the "in" of the sump but would worry that the unfiltered sump water going back into the display would be a bad idea.

A couple of things, I have lived in my house for now just short of 15 years. Last week on Sunday night, the main breaker to the panel fried leaving me with no electric until late Tuesday. Things happen.
I wouldn't use your canister filter as the return pump since you will need to clean it from time to time which will mean you will have no circulation on the 2 tanks while this is happening. Also, as time goes on, your flow rate will slow down due to the filter getting dirty. It might be fine for one tank but not the other. (All depends on the bioload in each tank.) A dedicated return pump is a better choice IMO .

 

[Vaesive]

A couple of things, I have lived in my house for now just short of 15 years. Last week on Sunday night, the main breaker to the panel fried leaving me with no electric until late Tuesday. Things happen.
I wouldn't use your canister filter as the return pump since you will need to clean it from time to time which will mean you will have no circulation on the 2 tanks while this is happening. Also, as time goes on, your flow rate will slow down due to the filter getting dirty. It might be fine for one tank but not the other. (All depends on the bioload in each tank.) A dedicated return pump is a better choice IMO .

I hope you know how greatly I value all your input! I'm taking notes and really do appreciate it!

Unfortunately that new link is a "Page Not Found" >.< The Bioload on the sump should be next to 0 if it's just substrate and plants, yes?

Ok, so I need to look into the following

• Dedicated Return pump that has a gph that is slightly lower than the overflow gph
• External Overflow box that can work with the Fluval 407
• Submersible Pumps?

 

[Andy Sager]

I hope you know how greatly I value all your input! I'm taking notes and really do appreciate it!

Unfortunately that new link is a "Page Not Found" >.< The Bioload on the sump should be next to 0 if it's just substrate and plants, yes?

Ok, so I need to look into the following

• Dedicated Return pump that has a gph that is slightly lower than the overflow gph
• External Overflow box that can work with the Fluval 407
• Submersible Pumps?

Hmmmm, that's odd. The link works for me. What you can do is google " Pictures of aquarium sumps" so you can see the different ways they can be done. ( I just wanted to show you different ways of setting them up and a picture says 1000 words. )

I did a search for submersibles so you should do the same. I did "Best sump pumps for freshwater aquariums. " Once you get this, check for which ones have adjustable flow rates as well as "in the tank" (vs needing a hole in the tank for the plumbing.)

I did a search for "Best overflow box for a 40 breeder" so you should do that and see what the flow rate is for that and match a return pump that matches or is less than that.

According to what I've seen, the Fluval 407 comes with all the hoses and machinery to run without any additional equipment needed.

Lastly, once you tie the 2 tanks together, the bioload is a combination of the two tanks, not each tank individually. So overcrowding one tank because you have nothing in the other tank is not really a good idea for example. Consider the system as a whole when considering what you want to do.

 

[Vaesive]

Hmmmm, that's odd. The link works for me. What you can do is google " Pictures of aquarium sumps" so you can see the different ways they can be done. ( I just wanted to show you different ways of setting them up and a picture says 1000 words. )

I did a search for submersibles so you should do the same. I did "Best sump pumps for freshwater aquariums. " Once you get this, check for which ones have adjustable flow rates as well as "in the tank" (vs needing a hole in the tank for the plumbing.)

I did a search for "Best overflow box for a 40 breeder" so you should do that and see what the flow rate is for that and match a return pump that matches or is less than that.

According to what I've seen, the Fluval 407 comes with all the hoses and machinery to run without any additional equipment needed.

Lastly, once you tie the 2 tanks together, the bioload is a combination of the two tanks, not each tank individually. So overcrowding one tank because you have nothing in the other tank is not really a good idea for example. Consider the system as a whole when considering what you want to do.

Awesome, here are the pieces of equipment I'm looking at
Overflow Box | EShipps PF-800 rated for 75-150g with max 800gph
Return Pump | SICCE Syncra Silent 1.5, Submersible, Adjustable Flow Rate up to 357gph

I have a bunch of spare clear hose line I was planning to replace the Fluval 407 hoses with for a more "clean" look so I should be able to use the excess for setting up the second sump tank.

Seriously, I cannot thank you enough for the help you've provided; I am truly grateful!

 

[Andy Sager]

Glad to help.

 

[Vaesive]

I've attached my proposed setup and it got me thinking if I really need an overlfow? Forgive my naivete but shouldn't the cannister filter provide what I need from the Overflow box? And it shold prevent any reverse siphon issue should I lose power, correct, and then all I'll need to worry about is whatever water is left in the lines back draining into the sump?

 

[Aiken Drum]

If the flow from your 407 and the return pump didnt match exactly would one tank get drained and the other overflow?

 

[Vaesive]

If the flow from your 407 and the return pump didnt match exactly would one tank get drained and the other overflow?

ooooooh. Yeah, haha, that would definitely be an issue...

But wouldn't that also be an issue with the filter attached to the overflow? Should I move the filter placement to replace the return pump instead?

Something like this?

 

[Aiken Drum]

Im by no means an expert on this having never set up a sump, but my understanding you can only have 1 pump so the flow is controlled by one source. I agree you would have the same issue if the 407 was fed from an overflow.

You normally have an overflow so gravity feeds the sump, and a return pump, or in your case the filter with your revised schematic. You latest setup seems better, but i do see a potential issue.

The input from the 407 is gravity fed via syphon action. You show them at the same level and although ive never tried running them them level i would imagine it wont work. You would need your main tank above your sump tank and your sump tank above your fluval so water can flow downhill via gravity and the filter can then return it to the main tank. If both the sump and filter sit at the same level you might get a little bit of flow into your filter if your sump tank was taller than the height of your fluval, but not very much.

Im going to have a careful read through your thread, see if im missing something.

 

[Vaesive]

Im by no means an expert on this having never set up a sump, but my understanding you can only have 1 pump so the flow is controlled by one source. I agree you would have the same issue if the 407 was fed from an overflow.

You normally have an overflow so gravity feeds the sump, and a return pump, or in your case the filter with your revised schematic. You latest setup seems better, but i do see a potential issue.

The input from the 407 is gravity fed via syphon action. You show them at the same level and although ive never tried running them them level i would imagine it wont work. You would need your main tank above your sump tank and your sump tank above your fluval so water can flow downhill via gravity and the filter can then return it to the main tank. If both the sump and filter sit at the same level you might get a little bit of flow into your filter if your sump tank was taller than the height of your fluval, but not very much.

Im going to have a careful read through your thread, see if im missing something.

I appreciate your diligence and input. I wasn't aware that the cannister filter is gravity fed, I always thought it provided suction... In that case, the first powst that included the overflow with the canister filter is ideal because I can prop the cannister up on something to be above the sump and still be below the main tank, correct?

 

[Aiken Drum]

But you would still have the issue of the filter and pump working at different rates. One or the other tank would overflow. Or the canister would end up running dry and that would burn out the impeller pretty quickly.

I think andy was suggesting you set up the tanks as a traditional main tank and sump with overflow and return pump, and if you wanted the cannister to provide your filtration set it up separately to one or the the other of the tanks.

Sorry, im not great at explaining what i see as the issue.