DIY Overflow - Sucking from the Bottom

[andywg]

aaaah, i see what you mean. couple of things to note though. the corner piece surrounding the standpipe is usually called an overflow.

one thing is that the top of the overflow would have to be sealed in order for it to suck water in through the bottom, very similar to the construction of a durso standpipe.

the other thing you would have to worry about is it sucking your substrate up too, which is usually the main problem trying to have something sucking water from the bottom, especially if you use sand.

In the UK they are generally referred to as weirs; an overflow relates to what you posted (a way of getting water out of the tank without drilling). Good old international differences

You have the bottom around an inch or so above the substrate and you should have no problem with it taking the substrate up. You would want most of the top sealed up to make it suck from the bottom (on the outer weir/overflow) but you want a small amount to come across the top to prevent the water on the top of the tank from stagnating. If you have the outlets fromt he pump return above the water then this would probably become unnecessary.

This is one of the best ways to prevent build up on the bottom of the tank without adding extra pipes and such to a sumped tank. Also gets good top to bottom circulation in the tank (all too often in sump systems you are taking water from the top via the weir/overflow and replacing at surface level).