Sump planning…

[castle]

Hi,

I’m in the process of planning/ordering a new aquarium. And I think a sump makes sense for me.

I plan on having a drip system into the aquarium via an HMA 15 meters away. As this means over time the aquarium could flood (doubt it with evaporation) I need a way for the aquarium or sump to drain into the garden/sewer etc

The main aquarium is 180x70x60cm. I’m thinking I will need three holes drilled and plumbed; one to drain the whole tank, one for an overflow and another is sump return/outflow. Does that seem right?

The sump, I’m less sure about; is there a nice way to capture overflows in sump? Can I easily do a water change with sump? I’m guessing shut drain pipes from main tank and then fill up the sump and let the return pump carry the new water back up?

Or should I just drill two holes for drainage and then run a large external filter?

I’ve never designed a sumped system; so definitely after some advice 👍

 

[_Maq_]

180x70x60cm

Do you think that a tank this big is small for bacteria?

 

[castle]

Do you think that a tank this big is small for bacteria?

I couldn’t say; I would guess there would be more bacteria in this tank when compared to something smaller (of a similar style) but whether there would be more bacteria in 1% of this volume vs 1% of another tanks volume is something I couldn’t really say for certain.

Think of the sump for this tanks as less about filtration/export and more about aquarium plumbing. I also like the idea of a large sump as I can house bullied fish in it, if needs be.

 

[zozo]

I will need three holes drilled and plumbed; one to drain the whole tank, one for an overflow and another is sump return/outflow. Does that seem right?

Could be, hard to say with too little information... Whether it all works or how it works is not alone in the holes you drill but in the tubing construction, distance and diameter connected. Even if you would work out and plan the entire idea on paper first with a drawing and dimensions etc. It still often is a gamble how it actually will work in real-time. Fluid dynamics can be somewhat tricky to predict, it isn't always a constant and it can change over time with tubes and guards etc getting dirty. Especially if you have no experience with sumps and fluid dynamics and it's physics. That would be building a brainchild on best guesses and the experiences after it's taken into use it's going to tell you how and if it works and if things need to be changed.

You could be very good at what you do or just very lucky that it will run a charm from the start... I don't know and I can't say...

Anyway, the drain capacity should always be equal to or preferably greater than the fill capacity (pump capacity | speed). The best is to have 2 drains working at the same water level if 1 restricts there is a second as fail-safe. If the pump delivers 300L/h the drains should have a higher capacity to drain when clean. So there is room for getting dirty and staying up to the task of draining 300L/h. This might be quite a challenge to calculate if so and you choose the tubing size on the best guess it's even better to build in a Shunt to regulate and lower pump capacity to sync it with the overflow capacity.

over time the aquarium could flood (doubt it with evaporation)

Flooding prevention is rather simple and all in the volumes...

The drip system could only flood the sump since the tank drains to the sump... Evaporation also only affects the sump never the tank. The tanks stays at it's drain level and evaporation lowers the level in the sump.

However, the sump will also need an overflow drain to the sewer in the compartment with the highest water level with the use of a drip system preventing the sump from flooding. And always drip the sump, not the tank and use a floater switch with magnetic valve as fails safe.

Then decide how high you want the water level in your tank for example you set the tank drains on a water level 3 cm from the top rim. Then calculate the volume of water left needed to flood it. that would be 3x180x70 = 37800cm³ = 37.8 Litres to flood the tank.

Now we know we only need about 37 litres making it critical and dangerously close to flooding the tank if the drains of the tank for whatever reason fail to drain. Then calculate the volume of the sumps compartment where the pump is in. If this part of the sump has more volume and contains more than 37 litres and the tank drain fails then the pump will still keep pumping all out of the sump into your tank and flood it. That's simple logic, isn't it? Thus simply make sure the pump is at a level so that it will run dry if the sumps is drained with for example 33 litres. And 33 litres can never flood the tank.

The last compartment of the sump where the pump stands should not hold more water. Or raise the pump on a platform close enough to the surface that it only can pump out less than the volume needed to flood the tank. Then it will run dry, good aquarium pumps have a thermal burnout protection in case of dry running. But long before it's running dry it will gasp in the air and you will definitively hear this and get alarmed the water level in the sump is low. Beter make sure you buy a pump with a dry run protection in case it happens overnight or while away.

 

[Wookii]

Great advice from @zozo already, so just a few additions from me, as there is a lot to cover in your OP.

First thing I will say is go with as large a sump as you can fit - this will maximise your safety margins when the display tank drains to the sump. Any time the pump switches off water will obviously drain from the main tank to the lowest available outlet hole, so the sump needs to be able to take this additional water volume over its typical operating volume.

Drip Water Change:

A continuous drip water changing system is going to be very tricky to implement on a sump, and I don't believe it can be done simply with an overflow outlet on the sump.

Take a scenario - you have the normal operating water level in the sump at 75mm above the pump as per @zozo 's recommendations above. So you cut your sump overflow for the drip water change system just above this to maintain the 75mm water level. You than have a power cut, or the pump fails, and the display tank drains into the sump adding a further 200mm of height to the sump water level. This of course disappears down the overflow. The power turns back on, and the pump proceeds to drain the sump dry up into the display tank.

But then you can't place the sump overflow higher than your target water level, as the drip water charge system will simply slowly raise it up to that sump overflow height.

My auto-water change system is a measured volume system. So identical containers for waste water and fresh water. Waste water is pumped from the sump into one container, and second container filled with fresh water (from an RO system in my case) is pump back into the sump - once complete the waste water container is pumped empty to the household drain or garden. This ensures identical volumes of water are changed each time. If you want your water changes to be on a more continuous basis the containers don't even have to be very large. Two small 10 litre containers would fit under the tank easily and could be set up to complete 10 litre of water change every 3 hours say, giving you a little over a 10% daily water change. You just need timers for the various pumps, and float valves on the container inlets. Lots of design options for additional fail-safes too.

Display Tank Overflow:

You also need to decide exactly how you are going to outflow from the main tank. Typically this is with some sort of overflow weir that water flows over, and then either drains from internally inside the tank to the sump, or is fitted to an external overflow box that in turn flows into the sump. Personally I would recommend the latter as it's easier to install and maintain and can be completely removed if necessary without draining the tank.

You then need to decide on a drain system - the dual outlet 'Herbie' style mentioned by @zozo is one option, with a control full siphon drain, and a secondary partial syphon drain that adds spare capacity in the case of more water needing to be drained from the display tank (e.g. pump fault leading to power increase). The 'Bean animal' configuration takes this further by adding a third emergency drain, altering the pipe configuration to minimise drain noise, and generating an auto-start system for the drain regulation.

I've implemented the Bean Animal system and it'd been flawless from day one. I think you may have read my journal thread already, but I've put a fair bit of detail in there on the overflow and sump if it's of any help.

Remanso . . .

 

[dean]

Im my experience you only need one hole in the tank usually in the base to overflow into the sump

In the sump have an overflow hole in the first chamber

Fit the fresh line drip in the pump chamber
If you drip in constantly theres no need to do water change so no extra holes are needed

If you want to do water changes then you need to add extra hole in sump and turn a valve or remove the upstand pipe to empty % of the sump but then you need to have the fill pipe on a float valve


Hope that helps


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[Wookii]

Im my experience you only need one hole in the tank usually in the base to overflow into the sump

Personally I'd never have a hole in a tank base. If the seal ever fails, that's your tank empty all over the house.

 

[castle]

Oh wow, there’s a lot to unpack here.

I guess the key thing I want with this is to have some kind of plumbing in place to make water changes easier…

I was thinking i would have had an overflow, really just a 90 degree elbow maybe equal with water level, so this would only drain every now and then due to the surface tension of water. This doesn’t really work right, for at sump at least now that I think about it. It feels like the right thing for a drip feed, but maybe that’s not actually what I need.

A tank this size; with the emergent growth I have planned doesn’t need a sump; but I do need a way to make water changes/top off as easy as possible. I can certainly have a drain out, under the floor and into a sewer.

Water in I would do something similar; maybe even go through some kind of mixing box to get it to temperature from hot and cold? Then through HMA to tank?

Maybe not a sump then, but still wouldn’t mind that hospital tank under there….

I’d still run a big thermo oase external; for the heater 😅

What’re your thoughts?

 

[Wookii]

I’d still run a big thermo oase external; for the heater 😅

That would be woefully inadequate, in filtration terms, on a 750 litre tank - what are you doing for flow? Maybe supplement with a Aquel Hypermax or similar.

Ultimately sumps are the easiest filtration systems to manage in my opinion, and they provide the best space for keeping all the unsightly equipment - heaters, CO2 kit, dosing equipment etc etc, but they are perhaps the most technically challenging to set up.

That said, if you are not dead set on a sump, and are happy with closed loop filters like canister filters, then a drip water change system suddenly becomes very easy to implement as all you need is an overflow outlet on the display tank going to the household drain.

 

[foxfish]

There are numerous ways to form an overflow, my own preferred method is a cut out at water level in the tank glass, rather than a hole! Unfortunately this is only really feasible on a custom built tank.
The cut out will depend on tank size but on my 200l it is 150 x 28 mm so that allows a huge flow rate and a buffer for any debris that that might collect.
I also prefer a return ‘over the tank’ rather than through it. This way you dont get hardly any issues if the pump stops working. I usually implement a spray bar so the syphon will break almost straight away if the pump stops working.
Personally I would never return water through a drilled hole in the bottom of a tank as this means you have to rely on a none return valve and from my experience they are not very reliable or fail safe!

Castle, you might be able to set up an auto water change quite easily by fitting a 6mm ball valve on the rim of the tank. (Or sump if you go that way)
These fitting are available from RO water treatment suppliers, just like a miniature version of what you have inside your toilet!
The tricky part is getting the water to the valve but, as the supply is only 6mm flexible, white plastic pipe it can be routed fairly easily from any nearby mains water supply, perhaps under the kitchen or bathroom sink.
Then you can remove water from your tank via a tiny power head, also using 6mm pipe (silicone airline).
This little pump could be adjusted to run permanently but better to have it come on for a few hours and then off for a few hours just in case the ball valve can not keep up!
I have probably not explained any of that very well but please ask if any of it appeals to you.

 

[dean]

Personally I'd never have a hole in a tank base. If the seal ever fails, that's your tank empty all over the house.

Thats how all the sumped tanks are made that ive used or have ever seen
Overflow weir and a hole in the base


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[dean]

Castle
Is this going to be a planted aquascape with light amount of fish or more fish than your typical plant person would use more of a fish keepers tank ?

I have an hma that is connected to a shower valve so it gives me the right temperature filtered water

If you want to keep it simple then how about this
An overflow using 3/4 inch waste pipe 90 degree one pointing up that sets the water level - you can put a piece of pipe in it to extend it up if its too low

Then just a 6mm tap on the pipe from the hma
Turn the tap on and the tank with overflow
You could leave it dripping in knowing you cant overfill the tank or you can turn it on fully to do a faster water change - remember if you are mixing fresh water into the tank then taking water out it will be diluted so you will have to change a much bigger volume of water

If i was doing this simplified no sump version then i would set the flow to add in 50% fresh water over a week

One thing to remember the longer the run from hma to tank the more heat will be lost by a 6mm pipe so i probably just use a cold fill and the the heaters run a bit more


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[dean]

If its 750 litre
Thats 375 litres in per week
53.5 litres per day
2.23 litre per hour
So that is literally a drip feed


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[castle]

Even more to think about! Thanks all, as this does give me plenty to think about.

@dean The fish tank will have plants in it, but I guess they’re not the focus. It’s a fish tank, but it won’t be over stocked. Maybe 100 fish; the idea is to get a group of Geophagus or Biodatama; with some tetras and small cichlids. Really depends on the hardscape (trees) I find in the floods.

Is there a way to calculate what the temperature shift will be on adding cold water constantly to a heated tank? If it means I have a 500w heater on 12 hours a day, that's about £2 running cost 😩 okay, not super unreasonable, but thats still 650£ a year. If i'm adding 30L a day, really this shouldn't be that much of a bother. The thermal mass of this aquarium should keep the room a couple of degrees hotter than the rest of the house, right?

@Wookii
😅 but how important is flow? If I have no need to grow demanding plants, won’t be using co2 and really am just expecting to have a brown water twig fest, do I need much flow? genuine question, and feel free to send to another thread. I've never had high flow tanks; at most my filters are maybe 2x turnover an hour 😅For nutrient export I suspect once the monstera gets going it should do the majority..

@foxfish I followed what you've said perfectly 👍 I quite like the idea; I think it would work very similar to what you're suggesting. I think.

So... maybe not a sump.

... Probably one hole drilled for overflow. Upturned elbow, will it be noisy?
... HMA to 6mm tubing, to 6mm ball valve to feed in some water at a rate.

simples?

 

[zozo]

A sump is rather easy if you keep it simple... You don't need a lot of flow in a low-energy tank with easy plants. I don't remember how much turnover my sumped aquarium has, it's I believe a 400L/h pump that doesn't turn over full capacity. Never measured it because I don't care... The easiest would be an overflow box you can buy hang-on versions or for drilling and mounting on, you could make them if you are a skilful DIY'r pretty cheap. Depending on how keen you are on aesthetics you can go wherever you want with it make it nice and tidy or just functional. I made a few hang-on mini versions from PVC fittings and tubing and works a charm.

This is my little sump, but you can make it as big as you like there are no limits.

And here both DIY overflows.

Here is a detailed explanation of how they are made.

Why don't we use sumps?

As the title says really. I'm planning my new tank and whilst thinking about filtration I was wondering why we don't use sumps like our marine friends do? Lots of space for filter media, big pumps pushing that 10x turnover easily, CO2 and any dosing equipment hidden out of the way. Aside of...

www.ukaps.org

Hang-on overflow box works with a vacuum syphon and it's a simple design easy to copy if you look closely at the factory versions that are quite expensive to buy. The cost is not really in the materials I guess more in the demand, it's not something a lot of people buy.

Noisy overflows are a construction flaw in the tubing, you are working with gravity and the acceleration of falling water volume | mass in a tube. It can gurgle, burb, blob, slurp, splash, whistle and or make peeing sounds or all together. You should prevent water from falling too deep and creating mass and velocity because then the tube will fill up and starts sucking air and that makes the noises. It can break a syphon, start slurping like mad in a drilled overflow or create bubbles and blobs in the sump. Then you have to break the route the water takes into sections and slow it down but keep the capacity up. Maybe a tad bigger tube or an aeration at the right spot. But these are things you have to figure out in situ.

But with a low turnover and sufficient tube capacity, this is not much of an issue to solve. Honesty demands me to say, it took me also a while to figure out why the darn system was noisy. But once I sorted it out and solved the issue it was also obvious and rather simple. Simple is easy to say but this is with all things once you learn from experience and once you see it and get that "Aha!?" moment then you know it and think why didn't I think of this in the first place? You won't make the same mistake twice.

 

[castle]

Needless to say, I’ve been thinking…

This isn’t a work of art, but stay with me 😅

Purple is drains to sewage
Green is return flow
Blue is incoming trickle
Red is drain to sump

I added two overflow in sump as emergencies
I added two drain in main tank; one to sump and one set marginally higher in case of drain becoming blocked and pump overfilling main.

I’m guessing I could put a float switch in the main tank which could power off/on pump? Still the emergebcy drain might be a wise choice


No idea how flows will go, but this is almost exactly as my last sump except… mains trickle and drain. I left a big area for fish/shrimp.

 

[castle]

This setup doesn’t mean I won’t do water changes; but this system means I won’t have to do as many.

 

[MartyK]

I would advise against the split on the red main drain to sump as well as the purple backup drain to sump being tied into the purple drain to sewage. The split on the main drain will make it more difficult to get a silent running system unless you add valves, which are a bad idea on drain lines, and also make actual mechanical filtration more difficult. The purple backup drain should enter the sump just as the main drain does but while the main drain should exit into the sump an inch or two below the sump water level, the emergency drain should exit into the sump above the water level so you can hear when it is in use - so you can hear when the main drain is clogged or restricted. If the purple backup drain goes to sewer then you just have a much more complex system that requires float switches (which fail all the time), backup water sources that could drastically change water parameters, etc.

Are you planning to drill the tank and have an actual overflow box or will you be using a HOB siphon-style overflow?

 

[zozo]

I would advise against the split

difficult to get a silent running system

Yup, that's too much and too long of a tube... Something like that will partially fill up with water and suck in air bubbles. Then you'll have 2 forces working against each other... A water volume with a descending rate, littered with air bubbles that have an ascending rate. This means a water volume that descends with x cm/s depending on the turnover with air bubbles in it that ascend in freshwater with +/- 25cm p/s.

Then you have something falling with something rising in it to make it a tad more complicated will result in a rather oscillating downflow of slurping and burping water in the tube and likely blobs in the sump..

To get an understanding of how this works you could use clear tubing then as long as it is clean you will see it happen and erratically bounce around in the tube. it can run fine for a couple of days and then suddenly start up acting strange. Little obstructions in the tube such as dirt, slime or algae build up can cause it to suddenly change. This is the best way to learn, to see what happens, use clear tubing... At least that's how I found out... Without seeing it it's hard to imagine what can go on in a drain tube.

But if you would do this... And make an open connection then the part with the split will become an open gutter, then it could work fine... That's because it's no longer a closed tube but aerated and all air bubbles leave the water volume at that point back into the air. Just make the diameter of the gutter a tad bigger.

Then if the standpipe | fall pipe connected to the tank still makes noise you have probably the wrong diameter vs. turnover.

 

[anewbie]

I only skimmed the thread but zoro more or less hit the major points; my aquarium has a sump and a drip system. The top of the sump has a drain hole where the excess water flows out; as to what you do with this water that is plumbing.
-
However, I wanted to point out some details that i ran into:
In general operation the sump has a max flow line and anything above this line needs to go out the drain; where you put that drain is partially determine by how much water will flow into the sump when the power goes out. In my case quite a bit of water drains into the sump when the power goes out until the stop hole is hit in the returns which is basically an air hole that breaks the siphon. The drain hole is nomally 1/2 inch so the hole is approx 3 inches from the top of the sump. However take into account that my aquarium is a bit over 550 gallons so there a lot of water that can drain into the sump that only lowers it a couple of inches. With a smaller tank or a larger drain hole the position can be adjusted. As for the rest of the sump design i much like this generic design:

http://www.swisstropicals.com/wp_site/wp-content/uploads/Sump-layout.pdf

Of course some details are left out - you don't have to use socks at the intake into the sump; but socks also dampen the water flow - though they aren't really needed for filtration and any-thing that prevents splashing such as a lid might be sufficient.
---
Note: in case it is not obvious but the return hose will become a backward siphon when power goes out so it will need a hole near the top that is submersed when things work but breaks the siphon when it breaks; conversely the end could be fastened very high near the top of the tank so it quickly becomes emersed when the power goes out.

But in your picture the intake is also low in the tank and that too will need to have the siphon break when the power goes out... perhaps i am stating the obvious