Water Change Drain

[Abyss]

Hi,
 
So I'm thinking of ways to make changing 50%+ of the water in my 1500L tank easier.
 
I want to connect my tank to the household drain under a nearby sink.
 
What is the best way to do this? I few shops have suggested drilling a hole in the side or bottom, connecting PVC piping with a ball valve and simply opening the valve when I want to drain the water.
 
This seems perfect, but am a bit concerned if that ball valve ever fails, it will drain the majority of water in my tank. This is because unlike the holes for the outflow and return pipes, it wouldn't be behind a weir and connected to my sump. If I put the hole for draining behind the weir, I'd only be able to drain the water behind the weir. So that's no good.
 
It's a bit of a dream to have a setup like this, and not have to get out pumps and pipes each time to do a water change.
 
Any ideas?
 
ps. the tank is still under construction so I can change anything with ease.
 
Thanks

 

[StevenF]

I am guessing your tank has a circulation pump to get some water movement.  Attach your drain line to the pump output with a Tee valve with no aquarium penitrations.  That way a fitting failure would probably not drain the tank.    Also set up your pump intake so that if the water level drops (say 30%) the pump will not have any water to pump to the drain.  That way the pump would stop pumping if the water level got to low.  

 

[Abyss]

Thanks for the reply.
 
I tend to use wavemaker style units for movement, but I could change if it works.
 
So, what you are saying is have a powerhead style pump in the tank, with an intake tube going say 70% down (to run dry when the tank is around 30% full)?
 
This seems like a good option if I'm thinking right. Only downside would be the equipment visible in the tank as I planned on having behind the weir or in the sump.

 

[StevenF]

 
So, what you are saying is have a power head style pump in the tank, with an intake tube going say 70% down (to run dry when the tank is around 30% full)?
 
This seems like a good option if I'm thinking right. Only downside would be the equipment visible in the tank as I planned on having behind the weir or in the sump.

No I meant 30% down leaving 70% of the water in the event of some sort of drain failure.  But that is only an example.  You can set it up any way you want.  As to the visual distraction of pipes you could hide them behind drift wood, decorative rock background or simply behind a lot of plants.  
 
If you don't have a pump it gets even easier.  Hook a pump onto the edge of the tanks with a intake pipe hanging down below it.  The pump output pipe goes to the drain.  Once you finish draining, remove the pump from the tank.

 

[Ch4rlie]

I had thought about similar set ups in the past, but figured it was a lot of trouble to do this, especially when ou have multiple tanks 
 
Its a nice idea, but a lot of planning and forethought needed.
 
I'll be keeping an eye on this to see what happens and may pinch an idea or two for my own set up in future perhaps

 

[DWC]

My tanks are much smaller so I use gravity and suction to remove 50% and stop automatically, as long as your discharge target, a bucket for me, the drain for you, is below your tank. I crafted essentially a squared off "J" of common 1/2" PVC fittings (two 90 degree elbows and some straight tubing) into a bucket. You could attach flexible hose to the end into your drain. The short arm of the "J" is in the tank (it's end covered with old nylon) and its length dictates when the suction, and water removal process, will cease. When I want to do a water change I just hang the "J" over the tank edge, start the suction (in my case just filling J in tank and then blocking long arm of J with finger until it is in hooked over edge position, and then releasing. Suction breaks and water change stops when water drops below short in-tank arm of J even if I am called away or distracted. In my case I have 5 (soon 9) tanks of the same size so very easy to move from tank to tank. Simple, easy, never fails and you haven't drilled holes in your tank. Size of pipe and height difference between tank and drain determine flow without need for pump.

David

 

[Abyss]

Thanks for the input.
 
Had a bit of a setback in that the place I was getting my tank from appears to have mysteriously and suddenly closed down after 18 years+.
 
Deposit was 50% which would have been a big amount given tank size. Very lucky I didn't hand anything over.
 
It's dissapointing as I'd been to the place, spoke in person to the staff and checked out some of the builds. Everything was great. Price, advice, delivery etc.
 
So, now I have to find another tank manufacturer! I wish someone in the UK made acrylic tanks in the size I want. Would save me bringing in a football team to lift its glass equivalent.