Hi All,

I am at a stage now where my tank has completed cycling and got minimal livestock, before I stock up and start adding a lot more biomass I want to get my sump/mini fuge going.
I am comfortable with doing the drilling etc, however the issue I have is what size diamond circular hole cutters I need for what size bulkheads.
My intention is to have one 3/4 inch overflow 5" from the plastic border at the top of my tank and another at 2".
Then a hole on the other side for my return from the fuge at 5".
So, if someone could advise primarily: Where is the best place to buy these fittings(online), which sizes I'd need, what drill bits I'd require, good affordable return pump and any tips on noise dampening from the overflows.

Thanks in advance


My tank is a roma 125, 2 common clowns, 1 blue damsel, small coral frags.
I intend on adding a 25ltr mini fuge and fittings hence this article.

Hi FRF,

Is this going under the tank like a sump?

If so, before you commit,  is 25L not going to be a bit small on a 125L tank?  Bear in mind you need to account for the water flowing down the drain, and syphoning back down the return line when you switch the return pump off.

My home made sump system is 27L on an 85L tank and I consider it a mistake that I didn't make it bigger for this reason.

Hey mate,
I plan on using a check valve on the return so that should remedy that issue.
Regarding the fuge generally I have read that 10% of total volume of the main tank can provide what is required? I won't be running immense reactors or anything just some chaetomorpha and a skimmer really.
My issue is the table I am using can only fit this specific tank underneath and be concealed.

Ah gotcha. I've got the same problem  with limited space.

A check valve on its own isn't too safe as they can jam open easily.  So one thing you can do is drill a small hole in the return line just below the water level, that way it will only drain the tank to that point when the power goes out.

Yes 10% is the normal figure for fuges with triton etc, but that doesn't take into account the space you need to leave for back flow etc. :)   Not trying to put you off it's just there is a very real risk of a flood if you cannot contain the back flow. I've done it three times now 



As an alternative there used to be a guy selling hang-on-back refugiums on ebay.  Can't find him now, but they looked like this:


Means you don't have to bother with drilling etc.  I'm sure you could DIY something ...?


edit: found him

https://www.ebay.co.uk/itm/Refugium-500RS-Stage-2-Skimmer-and-Heaters-required-Tunze-9004-Recommended/371467412590



another:

https://www.ebay.co.uk/itm/Cleartides-Refugium-500-500S/110756526524

Holy crap they aren't cheap though! At the moment I have everything but the means of putting the water back into the main tank...I have a little hang on box I'm using to keep the chaetomorpha alive ATM but it isn't doing anything.