View Full Version : My Sump Sketch / Design... Give an opinion please

05-24-2011, 10:42 AM
Hello everyone!

I've just registered to your great forum!

I used to be in the hobby for about 10 years during my early age (12-25) and then for last 13-14 years since I was moving almost on yearly base had to stop... Now I am planning to start allover again with a Discus aquarium of 500 liters (130 US Gallons).

I will be making my own sump for it, and for that project I have created a layout sketch which you can see here:


Question is - What do you think of it?

Basically the dimensions are: 100cm x 55cm x 45 cm which gives roughly 250liters but I calculate to be using only 150liters of water when the sump is done & filled in cuz of the lower levels in some compartments of the sump (one with bio balls & one with the reversal pump).

Please note that I'm a bit rusty when it comes to the expressions since I've lost touch with the hobby long time ago & I've forgot so many things. Also so many things are new & cool too me!

The compartment sizes are not precisely defined on the drawing since I would have to see them in real when the sump aquarium is in front of me so I can mark them with the masking tape prior to compartment dividers are set to place... but in general I believe it will follow this layout.

1st comp: will have two intakes draining into two filter bags sitting above some bio filter media.
2nd comp: will be a simple fish & plant refugium (which I plan into dividing into 3 sub parts)
3rd comp: will be a narrow compartment for few heaters needed to heat up estimated 650 liters of water (I hope to use 3x 200W or even 4x 150W heaters)
4th comp: will contain few levels of bagged filter media: Peat, Activated Carbon, Gravel, Ceramic Rings, topped with very fine filter mesh (not sure of the expression)
5th comp: contains a plate with many tiny holes over bio-balls which will cause water dripping over the bio balls (dry / wet system). Low water level due to the short divider between 5th & 6th comp
6th comp: return tank / comp. - with the water pump positioned near the water level.

Do you think I am missing something?
Any comments, critics... are most welcome!


05-25-2011, 3:07 PM
Seems the water from compartment 1 will fall to refugium, then to the heaters without much interaction..

Perhaps have the water pass though the wall bottom between 1 & 2

05-25-2011, 11:50 PM
Dear Lil_Stinker,
Thanks for your input. I will revise the wall structure there & make the small tunnel between comp 1 & 2 (wall touching the bottom & then one touching the top) which will make the refugium having better flow!
Any other comments?

05-26-2011, 1:02 AM
I am looking @ my sketch again & thinking.
In case I open the wholes on the bottom of the wall btwn com.1 * com.2 or make double wall so I have the flow from bottom to the top in com.2 - then I risk my fish getting into the hole on the bottom & sticking in there and having no possibility of growing the plants with the bottom.
Unless I open the hole somewhere like 5-10cm above the bottom & cover it with some kind of mesh which will not allow fish moving in com.1?
Hmmmm - a bit confused now on what to do.

05-26-2011, 2:43 PM
Make the first baffle out of a perforated plate, cut down an old under gravel filter or something. It should keep the fish in place and provide for plenty of flow.

Why do you need ceramic rings and bioballs? Aren't these redundant? I believe the bioballs will be more effective if used in a wet/dry trickle arrangement like you show. Submerged the rings should work better. In a sump you could always add air stones under the ceramic ring media and then do away with the bio balls completely.

I don't think you are going to have very effective mechanical filtration when it comes to very small particles. Add a whole house canister filter (big blue type) in the return line between the pump and the tank. The sump will be a great prefilter for the cartridge and remove the big stuff allowing a fine filter in the whole house canister with a decent life between cleanings.

Get rid of the last baffle between the bio balls and pump. What is the sponge going to catch that hasn't been caught by the previous stages of the filter? This will allow you to lower the water level under the bio balls giving you more room for more balls.

05-27-2011, 10:15 AM

I have updated the sump according to your comments, but I guess I will keep both bio balls & ceramic rings... nobody seems to be able to agree what is more efficient & bio balls are new technology for me so I would like to try them! When I was into aquariums they were not existing in Serbia where I lived back then.

Let me know if this is how you imagined it?
Thank you a lot for your comments.

05-27-2011, 11:27 AM
That looks great

05-27-2011, 11:52 AM
Glad you like it :)

My new question is - how strong pump should I buy for this setup?
Considering around 500liters in main tank + 170 liters in the sump (total = 670lit / 175US Gal) - and the fact that I would like to grow Discus in my tank so I need lots of filtration / circulation (with that BLUE filter between sump & tank)???

05-27-2011, 11:56 AM
My understanding is that the semi-aquas environment (media that is wet but also has contact with air) is the most productive environment for nitrifying bacteria. Hence bio balls when used as they were intended, surrounded by air with water trickling over them is pretty hard to beat for productivity. Ceramic rings work on the principal that they are very porous and have a huge surface area for the bacteria to form on. Since all of the oxygen for the bacteria to live on has to come from the water when the media is fully submerged the oxygen content of the water is the limiting factor for their productivity.

I have not seen it stated anywhere but my belief, based on simple logic, is that putting air stones under the submerged ceramic media will greatly increase the available oxygen and hence greatly increase the productivity of the bacteria. This is just my theory though. I would loose the gravel and replace it with the more of the more productive ceramic media.

Another benefit of bioballs is that they greatly increase the surface area of the water that directly comes into contact with the air there by greatly increasing the gas exchange... i.e. more oxygen in the tank water.

When comparing the surface area of ceramic media to the surface area of bioballs for a given volume of media the ceramic media will have many times the surface area of the bio balls. Hence bioball are much less productive in a fully submerged application. This might lead someone to question: Why not use ceramic media in a semi-aquas application instead of bioballs?

Bioballs, or any semi-aquas media does suffer one major drawback: When the water stops the bacteria quickly die. Hence your design of using both fully submerged ceramic rings and semi-aquas bioballs sounds like a very good one to me. If (when) you have an incident where the pump stops for what ever reason the bacteria on the bioballs will quickly die off. When the water is resumed the bacteria that is on the ceramic rings will start to re-colonize the bioballs.

On top of all this... bioballs are fun to play with as a filtration media!

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In your current configuration the water flows up through your main media column. You might want to consider swapping the heater compartment with the media compartment which would change the media compartment to a down flow design. My reasoning is simply that the water will hit the filter pad first, which will also be on top and easily removed for cleaning. This will keep debris from collecting in the bio media... and it is best to clean the biomedia as seldom as possible.

The trade off is that the up flow design is conducive to carrying the air bubbles up through the bio media. Depending on your flow rate and chamber size you might simply wash the air bubbles through the heater compartment when these two chambers are swapped. But if the flow rate doesn't over come the rising air bubbles you will have the water flow opposing the air flow creating longer a contact time and better gas exchange.

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One of the nice features of a sump is that the level of water in the tank remains constant with most overflow designs. The down side to this is the level of water in the sump changes considerably faster do to evaporation than one might expect. The collection basing in my sump is the entire bottom of the sump (no baffles) and I will loos about an inch of water a day in my sump do to evaporation.

In your design the collection basin is the last compartment where the pump sits. This appears to me to be a relatively small volume. If you remove the last baffle separating the pump compartment from the bioball chamber it would appear to me that you would effectively double the volume of the collection basin without changing the performance in anyway with the benefit of reducing the effect of evaporation on water level in the collection basin.

I think you misunderstood my recommendation, I recommend you remove the last baffle all together not just the sponge.

Your second to last baffle, the one retaining the bioballs, only serves the purpose of making it easier to access the pump. This is a very valid purpose but the positioning of this baffle should be placed such that you can easily remove the pump but at the same time maximize the volume of the bioball chamber.

To sum it up: in my opinion I think you have a very nice design.

05-27-2011, 12:04 PM
This in regard with the previous Q dealing with the water pump I was thinking of some pump that can get about 2000-2500L turn over in an hour. Do you think that's enough? That will give me aprox. 3 circulations through filter, and considering it's open type - I believe it's enough. What do you think?

Dear oughtsix - let me reply to your post a bit later. Thanks for the time taken to explain further. I feel good to know it's wise to keep both bio balls & ceramic rings :)
I will explain also the last part dealing with the last two comp. a bit later.


05-27-2011, 12:27 PM
I am using a Little Giant 3e pump rated at 670 gallons per hour in my sump for my 110 gallon tank.

I carefully chose the Little Giant pump on the basis of "it is what I had lying around". I would DEFINITELY NOT recommend this pump for this purpose per se. It is not a bad pump it just isn't really designed for this purpose. I am pleased with its operation though.

When selecting a pump you will want to find one in which the GPM doesn't diminish quickly with head pressure. The whole house canister is adding to the head pressure for the pump. With my little giant pump the apparent flow rate has not been reduced significantly with the introduction of the canister.

05-27-2011, 1:31 PM
Dear Oughtsix,


I share your understanding on the principles of working of BioBalls in Wet/Dry open system & the ones of the ceramic rings too. I am glad that you agree that it's wise to use both systems in the sump in order to keep bio-filtration alive on all costs. Adding air over the ceramic media is a wise idea - and I will for sure follow it. It cannot hurt & can be quite good I guess!


I followed one more of your suggestions & changed the order of heating part & main filtration media part! It's much better this way!

I was thinking the same about the air bubbles. Namely if the flow rate doesn't over come the rising air bubbles there will be flow opposing the air flow creating longer a contact time and better gas exchange. In other case - if I notice that the air bubbles are being taken away I can simply move the nozzle / stone above the ceramic media and it will bring air downwards if the stream is strong enough - which will be easily visible.


I am aware of the evaporation problems. I am thinking of creating some kind of auto refill system that will contain aprox. 20lit of water which I believe could be sufficient for a day and which I can simply recharge every evening!
Maybe some system like that exists already... gotta check the net though I have some simple ideas that I am thinking of.

On the other hand I will have both the main tank & my sump covered so I hope it will put the evaporation levels a bit lower... we will see.


As drawn & estimated - last two compartments will contain around 40l (20lit each). I hope that's enough water... or am I mistaken?

There is according to the current illustration about 20lit. of space for BioBalls. I believe that's enough of them for 670liters of aquarium? What do you think?

As for removing the last baffle - I was believing that it's the hight of that baffle that defines the level of the water in the COMP.5 with the bio balls. If I remove it wouldn't water level raise higher? Or am I thinking wrong?


As for the pump - I guess I will be going for a similar size of pump like your one. I just don't know which brand to choose. Will have to investigate a bit more in that field. So many new things in the shops since I left the hobby :D Amazing!


Anyway - sump design now looks like this:

Thank you a lot for all your inputs!

05-27-2011, 3:37 PM
As for removing the last baffle - I was believing that it's the hight of that baffle that defines the level of the water in the COMP.5 with the bio balls. If I remove it wouldn't water level raise higher? Or am I thinking wrong?

Anyway - sump design now looks like this:

Thank you a lot for all your inputs!

This is the only point in which I believe you are incorrect. If the water height is above the top of the last baffle the last compartment will fill to that height. If the water height is not over the last baffle the pump will drain the last compartment and run dry even though there is sufficient water behind the last baffle to keep the system in operation. The only case in which the water level in the bio ball compartment will rise above the bottom of the bio balls is when both compartments are full and the water level in both compartments are above the bio balls. With this level of water the bio balls will be submerged whether the bulk head is there or not. Now if you always wanted to ensure that the bottom of the bio balls were submerged then the baffle would have a purpose.

The last baffle will maintain a minimum water level in the bioballl compartment but it will NOT ensure you don't go over a maximum level.

With 20 liters in the last compartment you will probably have plenty of buffer volume. But if you remove the last baffle would will have much more buffer volume. What do you think you will gain in the system from the last baffle?

If you remove the last baffle you can run a lower water level in this catch basin but still maintain a greater volume of water in the catch basin. This will allow you to lower the bio ball retaining eggcrate and have a great volume of bio balls if you wish.

You are correct in that the system should function just fine with the last baffle in place. It is just that the last baffle serves no purpose and is not adding any functionality to the system.

My recommendation would be to remove the last baffle, lower the bioball retaining eggcrate, make the bioball chamber proportionately narrower to still retain the amount of bio ball volume and then add the extra space to the refuge.

Your welcome, I enjoy the design process! :)

P.S. I can't wait to see your build!

05-27-2011, 4:04 PM

I don't believe that an auto refill system would be needed with your sump. The volume of the catch basin will act as the buffer for an auto refill system for the tank water level.

From your description of everything being covered to reduce evaporation I would venture a wild guess that you could run the sump in the configuration shown easily for a week without having to worry about a refill. I believe that if you removed the last baffle you could probably run pretty easily for a couple of weeks (with twice the volume in the catch basin).

My 110 gallon tank has an open top and my much smaller sump is almost completely covered except for the area immediately around where the exit plumbing leaves. In a very dry desert climate I can run almost week without having to worry about refilling the sump. I really like that my tank is always at the same level and doesn't drop a 1/4" to 1/2" everyday. Because the level change is more profound in the sump it is easier to get a quick visual reference as to when refill water is needed. I will be covering my tank now that the weather is starting to warm up to keep the humidity levels in the house in check. The extra aeration provided by my sump gives my the confidence to cover my tank and not starve the fish of O2.

05-29-2011, 3:26 AM
Curious as to how you intend to make regular water changes.? Are you building some type of system into place.??
Have never kept discus but those I've seen use either "open flow" or Veggie filters for display tanks One changes 50 percent every day for the grow out tanks bare bottom with only a few floating plants for cover.
Assune you're using this sump on a display tank?? gary

05-29-2011, 12:23 PM
I would have added an overflow . . . but then all your baffles would have to be lowered. My 2

05-29-2011, 1:10 PM
I'm not sure if this has been mentioned, but I think it might not be most efficient for the heaters to be before the bio-balls. I have never built a stump, but I would think that because the water would have lots of surface area exposed to air (the whole reason for a wet-dry), it would allow more heat exchange. So by oxygenating the water, you may also be cooling/heating it as well.

To fix this, I would recommend putting the heaters after the bio-balls, either in the narrow compartment between comp5 and comp6, or simply placing them before the pump.