I think they provide flood protection if the filters fail for some reason. I know when my filters are turned off, they spit a little water into the aquarium. If the aquarium is filled to capacity, that means the water has nowhere to go but out and onto your floor. With huge tanks, a filter failure means a whole lot of water. I guess...?
Or if a fish decides to splash a lot...or you put something heavy into the tank and water is displaced....
Thanks Jan You always come in "handy" with various technical questions, lol, like python or now the overflow hehe.
Just to be certain again, the overflow is placed INSIDE or OUTSIDE the tank? And how does the water drain into the the overflow if the aquarium is the same height on all of its sides (it's trim is level around all sides of the tank). It seems you'd need to have some "cavity" or a little "hole" cut out in top of one of the walls (that are level) in order for water to drain into the overflow. Because when the water starts to over-flow, it spills out from all sides if walls are even.
It's a piece of equipment, not an actual tank. I think if you have a tank connected to your overflow, that's called a sump. Overflows can be built into your main tank or attached to one. Once the water in the tank goes over a certain level, the overflow kicks in to maintain that water level. I don't think the water goes anywhere if you don't have a sump attached, the overflow just pumps the water faster through its mechanisms so that it won't spill out of the tank. I THINK? Geez, someone else needs to chip in. I don't have an overflow or a sump.
From what I understand they are only really necessary for filters other than internal or HOB and a simple one I believe is with a chamber inside and outside of the tank so it's hanging on the back and as long as the water level is high enough it flows into the box and a tube sucks the water from the inside of the compartment to the outside and there is a hole in the outside one and it drains into the sump or whatever and if your electricity fails as long as you don't accidently fill your water level up too high it can't overflow onto your tank. Are you considering building a sump, if you are PM me i can help, I had wanted to once but was never allowed. Just a thought, maybe you should make a 75 gallon tank planning thread so all your questions are on one post.
Thank you all for trying to explain to me what overflows and sumps are; I really appreciate
After reading the article ... it seems like it's a good thing to have, but it seem so complicated to set up! Not my kind of thing. I am not really good with "tinkering" with "this and that" and since this setup seems like it's complicated, I won't have the time for that. Unless I could buy everything ready-made.
Is this thing really necessary in a 75G tank? Do you have that in your 75G, Carol? Or can I just set up my tank in a simple way, either with a regular HOB filter or a canister filter? I don't have the time for too much hassle, and I want a tank set up in a way that is easy to clean and to take care of. The only reason I am buying it is for my fish to have more space and to accommodate my baby angels. It's nothing like a high-tech show tank.
ATM, yes, I probably will make a separate thread about a 75G with various questions on planning. Thanks for the suggestion and for offering help with the overflow