Im still in the planning phase

[tonypun]

Hi All. I am new to the forum and new to the hobby. I used to keep tropical years ago and would now like to set up a marine tank.

I have space for a 78 x 17 x 24 inch tank (custom made) plus I have a 36 x 12 x 18 tank that I will use as a sump and refugium.

Unfortunately where the tank will go there is no space for a sump beneath and I dont want to use space in display tank as a sump.

So to my plan and this is the bit I would like someone to sanity check for me that it will work.

So the display tank will have an overflow weir. I will install a pump in this overflow that will have enough head on it to get it to the loft where the sump will be, the pump will be activated by a float switch which will keep the weir within a set of levels. Once the water reaches the sump it goes through the various filters and chambers emerging at the other end via an overflow which will then gravity feed the water back into the tank thus topping up enough to keep the cycle going again.

I will have a normally closed valve on the return that will cut off the return in the event of a power failure and and also a higher level float switch to cut off the flow on the return in the event that the weir pump fails this should be a satisfactory failsafe.

I think in this scenario the auto top off will need to be on the tank side not the sump side as that is the level that I need to keep an eye on.

Does that seem to make sense or have I got so tied up in my own head that I have been blinded to an obvious issue

Quick sketch of design attached.
thanks all

T

 

[Rover88]

I'm going to greatly oversimplify what it seems you are talking about:

You want to have a display tank and a sump, except their roles are reversed. Normally a display drains into a sump, and a sump pumps to the display.


So long as you have enough room in the overflow to house a pump this in principle should work just fine. Don't overthink it; You don't need a switch for the pump, the pump should be pumping 24/7 all the time never stop it. It won't run 'dry' for the same reason normal sumps don't run dry; The water gravity feeding back down will keep it fed so it can continue running. Your auto-top-off would go in the same chamber as the pump, just like it would in a sump, as thats the only place the water level will ever be seen to drop with this sort of setup.

The big concern would be making sure your display tank has the space to handle the runoff from your sump in the event of a power outage or other such issue. You could have a check valve on the pump out, but you'd need to make sure you leave room in the 'display' for the runoff from the sump even with that, just in case of failures.

I can see issues with this mainly stemming from bubbles on the return line, and things like that.

 

[tonypun]

ok that makes sense [MENTION=368903]Rover88[/MENTION] thanks so much, your guidance is much appreciated.While we are discussing it could you sanity check this for me.

I would so if at worst my water level is only 2 cm from the top of the tank that would equate to 17 litres of water that could go in to the top plus if i had a weir 25 cm long x 15 cm deep that would be another 22 litres. So as long as the final part of the sump that drains into the tank plus what is in the pipe (22 mm pipe will hold .32 litres per metre x 4 metres = 1.28 litres) does not equal more than 39 litres I should just about be ok. it would not be the entire sump that drains as the water would be stopped by the final baffle once the pum stops putting more into it.

How do you mean bubbles on the return being an issue as in the water velocity on the return mixing air into the water and mixing air in to the water.. if so I could pop a "u" into the pipework to slow the flow would that help?
or alternatively have another chamber where the return water goes in and then have a gap half way down to prevent the bubbles from reaching the main aquarium water. see sketch attached.

much appreciated

T

 

[Rover88]

Where my water cascades down into my sump there are a fair few bubbles. If you have your water coming down into your display tank, but falling in and not being pumped in, I can only imagine it would give you the same thing.

You do not want anything at all to restrict the flow from your 'sump' to the display. If you do you risk overflowing the sump if anything were to happen to block the return lines.

You need to factor in all the normal considerations of sump to display flow, except you are looking at it in reverse.

As for the exact water calculations, you are correct. You don't need room for the whole sump, just what will be flowing back down into your tank. You want to plan for a little more rather then being bang on exact.... just in case.

 

[tonypun]

Thanks very much I think by the looks of it I am fine with the display tank capacity in the event of pump failure and sump depositing in the display tank. So I guess really the final baffle space where the hole will be at the bottom need only be as big as the pipe coming in to it. Doesn't need to be much wider than that and therefore increases the space for other sections.

I guess one concern could be the capacity of the sump to be able to take the contents of the weir in the event of the return being blocked that could be remedied by a level switch in the sump so that it cuts off the pump in the weir if the water level gets too high in the sump I,e it goes massively over the baffle height.

Do you think the bubble trap design in the last post would work in the main tank. It would auto level itself with the main tank via the hole half way down and this is only restricted by a weir comb to prevent fish getting in there.

Thanks again for your input with this. I would rather thrash this all out now at design phase so I know exactly what I am ordering..

Cheers

T


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