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Hi Everyone

I just wanted to ask those that are using overflows and sumps whether you are using pre-drilled tanks with a built in weir or hang-on-the-back style overflows? I had been using a hang on the back style, which worked well but the flow was pretty low and am considering a pre-drilled tank with a 1" drain, but still uncertain how much it would be an improvement (if any) over the hang on the back styles. For the sump I have always used bioballs but I've been thinking to switch to a refugium, has anyone found that a refugium with plants could help with dissolved O2 at night? I've been monitoring DO with an oxyguard sensor (10 min intervals) for a couple weeks and found that DO levels fluctuate more than I expected (3-4x less at night), but what is more surprising is that it takes nearly 11.5 hours for the saturation level to reach it's maximum (around 8pm right before the lights go out) whereas the minimum level remains from 4:30am till 9am (when lights come on). The tank is a (lightly/moderately) planted 55G with two Eheim 2076 filters and an ecotech MP10 for circulation. there are also two airstones in the back. I would like to maintain a higher DO at night so that is why I thought swapping the bioballs for a refugium (with the lights on at night or 24/7) could help.

I use built in overflows on all the tanks on my central system. I prefer the reliabililty and higher flow rates of the built in overflows. I also have plants in my sump instead of biological filtration. However I do have a lot of biological filtration elsewhere in the system.

My system consists of 2 120 gallon Oceanic tanks with built in overflows that drain into the sump. Also connected are 8 x 15 gallon tanks, situated end out, with Poret mattenfilters that form the back wall of the tank. A 1" drain is behind the Poret wall that drains down into the sump.

The mattenfilters provide all the biological filtration for the whole system. In the sump I keep some sword plants and some Crypt. ciliata in pots. The crypts do very well and actually kind of choke out the swords. I run the lights in the sump opposite that of the main tank. Main tank lights are on for 6 hours a day and sump lights are on for 18. Except on weekends when the main tank lights are on for 13 hours.

I would definitely recommend a built in overflow vs. a hang on for any tank wider than 18". For a 12" wide 55 gallon it takes up a lot of space inside the tank and it may not be worth it. You may want to consider adding an airstone to the sump to help balance your oxygen levels.

Andy

I've just setup two 100 litre tanks running from one canister filter using a pvc pipe overflow.

The tanks are for breeding Apistogramma in the upper tank and Endler guppies / growing on L144 Ancistrus in the lower tank.

I used Uaru Joey from youtube fame's direction on DIY aquarium overflow set up link here ~


It is working perfectly.

The only down side as is said is possible disease being passed from one tank to another but for this setup I am not concerned with that outcome, its just the same as treating one tank with the same fish in, the filter is rated to a 175 litre tank and I have the 100 litre tanks filled to around 60/70 litre each, I will be upgrading to a larger capacity external filter just as soon as I have the funds.......it will be totally fine and am VERY happy with the outcome

I would be very wary about using an overflow with a canister filter. Canister filters are closed systems that require a siphon to drain water down and then the pump returns the water back to the aquarium.

An overflow is an open system where gravity drains the water to the sump below. Overflows can and will draw in air into the drain water. Sucking air into a canister filter will at the very least make it noisy and at the worst cause it to lose prime and stop functioning.

I am glad it is working for you now but I would keep a close eye on it.

Andy

Drilled is the way to go IMO, especially if you're able to set up a 'herbie' or 'bean animal' type system (google it ;) ), though with only a single 1" drain you may be limited with the amount of flow you'll be able to have. Personally I wouldn't waste my time with a FW fuge, Pothos plants do a far better job of consuming nitrates and won't release CO2 back into the tank at night. I'm a big fan of the KISS principle (even though I didn't follow it with my own sump for several reasons), just a regular tub or old aquarium with no baffles, a felt filter sock (or two or three) and some mesh bags of ceramic noodles or matrix is all you really need for a FW sump.

Narwhal72 wrote:I would be very wary about using an overflow with a canister filter. Canister filters are closed systems that require a siphon to drain water down and then the pump returns the water back to the aquarium.

An overflow is an open system where gravity drains the water to the sump below. Overflows can and will draw in air into the drain water. Sucking air into a canister filter will at the very least make it noisy and at the worst cause it to lose prime and stop functioning.

I am glad it is working for you now but I would keep a close eye on it.

Andy

Is still working fine, the only loss I am getting is evaporation on the lower tank, its super quiet, just the overflow outlet into lower tank trickling, however there is a change in water depth when putting hand in upper tank e.t.c but is easily manageable, takes a bit of getting used to it and knowing the changes and compensating by adding and or draining to lower from upper but like I say it really does work, I used 22mm pvc for the overflow and the filter is an aquaone aquis 750 but I will be upgrading to a slightly more adequte filter for breeding in this aquariums, the aquariums are 100 litre 24x18x15 and filled to roughly 65 litres atm the upper tank has an unrelated pair of triple red cockatoo cichlids, the lower I am using as a grow on for my L144 fry and for at the moment a male Venus Guppy with a white dorsal and 2 true endler females...its going good....