Why some All-In-One Aquarium have a hole on the bottom?

[Aqua Splendor]

I'm building my own aquarium generally but i might buy one pre-made this time. I never had any issue to now to not do a hole on the bottom. I personally find the hole annoying and dangerous for live stock. Plus it's extremely distracting from a design point of view.

So... Why?
thank you

 

[GabeM]

Most I've seen have a weir there - there is usually a piece of plastic behind it going up to the overflow in case the top weir gets blocked ever.

 

[Aqua Splendor]

Yeah I didn't have any issue with either with my design... well... it's extremely borderline overflow.

 

[Tastee]

My AIO I use for my QT has the same setup - two holes in the back for the weir. Mine are both screened off however not open. You can see them

in the photo below.

 

[AquaholicAquariums]

That for the return pump not to run dry

 

[JumboShrimp]

Yes, you will want the hole for water to be drawn in from there and not solely from the top; and yes, the one in your original post is missing a pop-in grate. Best wishes on your project!

 

[Aqua Splendor]

Hmm
I much prefer to have the water uniquely drawn from the top to skim the surface. And... anyways the water when it reach that bottom goes up with the flow so...
I never had any pump running dry but that probably because I either add manualy water each week (otherwise it make sound) or i use a auto top off.

 

[Nano sapiens]

Hmm
I much prefer to have the water uniquely drawn from the top to skim the surface. And... anyways the water when it reach that bottom goes up with the flow so...
I never had any pump running dry but that probably because I either add manualy water each week (otherwise it make sound) or i use a auto top off.

Agreed. While the idea of having a low down hole so that the pump doesn't run dry is good in theory, in practice the pump running dry is quite unlikely (not topping off for a long while and possibly something completely blocking the weir come to mind). IMO, the benefits of a strong weir overflow far out weight the unlikely chance of the pump running dry.

 

[JumboShrimp]

Personally, I wasn’t focusing on the possibility of the pump running dry; I shove a wad of some good old filter floss down behind the bottom grate (hole) and assume I get some detritus drawn into the filter floss from down low in the tank.