Advantages And Disadvantages?

[Siamese Fighter05]

Hey Everyone

I did try and explain my plans for a new setup i'm hoping to start sometime in the future. It was at first going to be a 28g with a 16g Sump. That's now upgraded to a 50g with a 25-40 sump. Mr Miagi answer has triggered off some new questions...

My original plan was to drill one hole into the back of the tank and then fit in a Bulkhhead. A 90 degree elbow pointing upwards just underneath the surface would suck water down through the piping which would lead it into the sump. The plumbing needed would basically just be rigid pumping, a few 90 degree elbows and then a couple of unions for emergency access to the pipes.

Mr M has advised that an external overflow will give me increased waterflow therefore better surface skimming. He said the system will also run quieter with this method

This had made me consider going with the overflow instead as all of those reasons are what i really want from the sump. I'm suffering from surface scum, surface agitation in my nano and i really don't want to experience this problems with the next system as it looks damn right ugly

One thing i am worried about with the external Overflow is the risk of a fish jumping over or even more likely a snail going over and then blocking the piping which would cause the pump to flood my mum's flooring This is pretty common in threads i have read....

With the original design i could just simply cover the inlet of the tube with some mesh to stop fish/snails from getting in. This one is more difficult as i'd have to make the teeth really close together, would that mean i'd lose the amount of water passing through the overflow? Which would defeat the object of more flow/ surface agitation...

Could someone explain the Pro's and con's of each method and give me their opinion on what would be best.

If anyone has a good link to a site that explains all this i would really appreciate it

A link to an example of an Overflow box would be great too as i'm still not 100% sure on how they fully work )

Thanks Alot
Dan

 

[@ombomb]

a snail going over and then blocking the piping which would cause the pump to flood

That's what happened to me, although my overflow is internal.

Personally, if I was starting from scratch, I'd go with one of the options on this website I plan to modify mine to something similar in the next week or so.

 

[crazyelece]

I have used both systems. Either way you go you can use an overflow to surface skim the tank. For a drilled tank just use a piece of acrylic and cut slits in it then silicone it in the corner to create an overflow box inside the tank.

Anyway pros and cons of both systems

HOB or external overflow
pros
cheap and easy to get ahold of
simple to adjust
easy to get quiet
take less space inside the display tank
cons
have to maintain a siphon to operate successfully

Internal overflow
pros
always drain due to gravity so no worries on the siphon
cons
need special tools in order to drill a standard tank
need DIY skills to make and instal a working overflow box
take up a lot of space out of the display tank
need a duruso or other mod to get quiet operation

IME both work sufficiently well. I would go with an internal if you are able to build everything yourself. Go with an external if you don't have the DIY skills.

 

[Siamese Fighter05]

I really don't want to have an internal Overflow as it will look really ugly in the tank. The main idea of this was too keep all equipment out of the tank to try and make the reef look as natural as possible. I'd rather see a great big dirty heater and powerhead in the tank than an overflow box.

I found this design:

What do you think? This takes up such a small amount of room in the tank it would be perfect, i can't see it making much noise if any. Do you think to will well surface skim though?

I won't be doing any of the DIY work, Good God! It's scary to even think of The LFS or whoever makes the tank will do that job for me

Dan

 

[@ombomb]

Dan,

That would work, but if you're going with that design the best way to make it quiet is to put a 90 degree elbow inside the tank so that water is getting sucked UP into the outlet. Then a small air hole externally will stop the gurgling noise which can be a problem with overflows.

 

[Siamese Fighter05]

Thanks for the tip

I've seen this design somewhere on NR before but i can't find it anymore . I really think that this method suits me better but i really want to find out how good it is at surface skimming, wish i could find that thread!

 

[andywg]

To be honest, a mini weir that only just surronds the 90 degree elbow is the best option for th tank. Witht he weir you have better control over the water level and can drill lower.

External overflows have a nasty habit of losing syphon, and this is very bad. Reduced flow is not as likely and can be defeated (through a weir).

I have a weir for a 3x2x2 tank that measures an entire 5x5x6 inches in the rear corner, and could be a fair amount smaller in reality (like around 4x4x4). Build up some live rock and you would never see this. Other than that the drainage is similar to the picture you have shown.

I honestly don't see how external overflow syphons give you more drainage capacity. If you plumb a 110mm hole into the bottom of a tank it will drain at the same speed as an overflow with the same size plumbing.

Finally, a well set up durso standpipe will run all but silently.

 

[crazyelece]

If you want to surface skim your way isn't an option. It just won't do it. You can add a surface skimmer around the drain similar to how the nano cube surface skimmer works, but when you turn off the pump the skimmer will fall off.