Sump size?

[LucifersJester]

Hey peoples...

I am in the process of setting up (1x) 4ft x 2ft x 18" and (3x) 2ft x 2ft x 18" on a sump system.

Just a question though - what size should the sump be - approx.

I was trying to work out how large it should be - I do have a 4ft x 2ft x 18" that I can use as a sump (it's been broken and patched - looks bad but holds water well) - or I can make one from scratch...

Your thoughts would be appreciated.

Thansk in Advance

[CThompson]

Minimum sump size = the amount of water that will flow from a tank or system of tanks during a power stoppage.

For example, if your lowest point in your tank/s is say 30mm from the top (this will typically be your entrance or exit from the tank to the sump), then calculate this amount of water (length in centimetres by breadth in centimetres by 3cm divided by 1000) then by the number of tanks you will have your maximum runoff. This will give you a total amount of litres that will not be contained in your tanks and will return to your sump during a power stoppage. This can either be from a blackout, or more typically during water changes when you must turn the pump off at the switch.

Your sump needs to be in excess of a minimum of this size, so make it as big as will fit into the available space, and still comfortable to allow access to and make sure the empty space in the sump (i.e. space above the normal running water level in sump) is big enough to cope with this maximum runoff.

Craig

[Ash]

Just in case you are a bit confused, I thought I'd flesh out what Craig has said.

The repaired 4x2x18 should fit the criteria Craig has listed by a long shot - in essance you just have measurements of the running depth in the sump (how much the pump/heaters need to be covered) and the overflow/siphon depth (the 30mm Craig suggested in the above scenario) of all the tanks so you can work out the added volume in the sump.

In Craig's example, the 4 tanks' combined overflow at 30mm each should be ~75mm in the sump. If you only need 100mm in the sump for the heaters/pumps, there is a total depth of 175mm (aka 17.5cm) which in no way stresses your damaged tank/filter.

Of course my calculations are assuming all tanks have the 2x18 bit the same way around (doesn't matter if they are 2' high or 18" high, so long as they are all the same). Also if you have the return feeds to the tanks under the overflow level, these will siphon down to this depth once the power is out, so depending on your plumbing the 30mm figure is quite variable.

Hope this helps.

Ash

[ViS]

Minimum sump size? As big as you can fit and as big as you can afford

Maximum sump size? No such thing.

Good advice above. If you are worried about overflow, and the tanks are in the garage or similar, You can always overflow the tank to outside. It will still run almost dry in the event of a power outage and restart, but you'll avoid the flooded floor

I have an overflow from my sump, but also use a UPS so the overflow won't have to be used (hopefully ).

[CThompson]

(how much the pump/heaters need to be covered)

This is easily catered for as well. If you put a partition, high enough to take the length of the heaters when stood upright (i.e. with the top of the heater NOT submerged) at some point in the sump which will remain full with water independent of the rest of the sump water levels, this section will never run dry.

As requested, some further photos of the new tank.

If you look at the sump in the sixth photo down on this link above (have a look in the technical section, it is a few posts down, if link dosn't work), look at the right end and you will see how the heaters are set up. They simply cannot be run dry.

Craig

[AzFish]

as its been said, make sure the sump can take all the backflow of water for when the power goes out. I have a 4x2x2 with a 2x18x14 (lxWxH) sump, after i cover my heaters ( which are placed on the bottom of the sump complety submerged ) and cover the return pump its a 1/3 full, when power goes off the sump handles all the backwash and none on the floor!! in hindsight i would of gone a bigger sump, just so theres more room to play with ect....get what you can afford and make sure its bigger than what you think u need.

[LucifersJester]

Thanks for all your help guys - I really appreciate it...

If anything bad happens I'll let you know

Otherwise I'll put a post up when all is running -

Thanks Again

[Brayden's dad]

Minimum sump size? As big as you can fit and as big as you can afford 

Maximum sump size? No such thing.

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Troy.