# automatic top-up / water change



## gzylo (28 Dec 2009)

Hi

Does anyone have ever used http://cgi.ebay.co.uk/Liquid-Water-...ial_Automation_Control_ET?hash=item35a5e6b85e as a water level switch?


basically what I am planning to do is to do automatic water change system with RO/tap water mix under the tank with 1 pump to add water from it to the tank this one would be connected to the water level sensor. And another one sucking water form the tank to cabinet under kitchens sink. Second one would be electronically controlled by timer switch, every two days or so. Second pump would be faster than adding one.

Does any one have ever used anything like that? 


EDIT: Can anyone explain to me what is max switching voltage? 

thanks
gzylo


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## Ed Seeley (28 Dec 2009)

That all seems a bit complicated!  Why not just run the water from the RO unit into a sump straight from the RO unit with an automatic shut-off kit?  You can even use some of the waste water, controlled by a tap to just a trickle, to give you the mix ratio you want.  With the auto shut off kit it will turn both the waste and RO product feeds off at the same time so your tank doesn't overflow.


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## gzylo (29 Dec 2009)

Hi Ed


Simple because I would have to get the water out from tank manually - where I wish to get pump to take water out of the tank and put it under my kitchen sink where closest waste water to the tank is. Then I would use float sensor mentioned above to monitor water levels and top up same amount of water back to the tank from under tank reservoir automatically. The out pump will be set up on digital timer switch so I can control how much of water it will pump out as reservoir will be only 80L.

Hope that's clear


gzylo


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## daniel19831123 (29 Dec 2009)

Sounds good to me but how will you be connecting this to the pump? Will you be putting the switch in the main tank or will you be putting a overflow sump with the switch in it? If you have an overflow, you can just drain the water from the sump and it will automatically replaced the water there without affecting the level of water in the tank. Hence you don't have to turn off filter etc while the water level is low. 

I find that I have to turn of the filter and heater in the 60L due to the amount of turbulence it caused with substrate disturbance when the filter outlet is above the water line and I'm risking damaging my heater. Having the sump would have solve this problem.


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## Ed Seeley (29 Dec 2009)

gzylo said:
			
		

> Hi Ed
> 
> 
> Simple because I would have to get the water out from tank manually - where I wish to get pump to take water out of the tank and put it under my kitchen sink where closest waste water to the tank is. Then I would use float sensor mentioned above to monitor water levels and top up same amount of water back to the tank from under tank reservoir automatically. The out pump will be set up on digital timer switch so I can control how much of water it will pump out as reservoir will be only 80L.
> ...



Ok, that's not a problem.  Just have your waste water pump on a timer like you planned pumping the water to waste and then have your new water coming from your RO unit using an automatic top-up system in the sump (assuming you're using a sump?).

I'd make it a lot simpler though by doing the following (I'm assuming you don't have a tank with built in overflows and a sump filter here):
Have an overflow to waste which can be the very thin strong RO tubing plumbed into the tank wall or a plastic overflow box.  Water will flow via gravity trickle to waste irrespective of the distance as long as your waste pipe is lower than the top of your tank.

Have the RO input with the float valve hidden in a box at the back of the tank in the tank to top-up slowly as water trickles out.

Set it up so the automatic shut-off only stops the flow if the water level rises as the overflow pipe has blocked and adjust the rate of the old water leaving via a small ball valve on the waste line.  

This will give you a constant trickle water change 24/7 which will be fully automatic.  All you will have to do is check the system is working.  If something goes wrong it will be the waste pipe blocking and the system will shut-off until you unblock it!  

You can control the amount of water changed just by adjusting the ball valve on the waste line and it will just need to be a few drips a minute to change a lot of water over a week.  For instance a 200 litre tank needing a 50% water change (100l) over a week will need only 14.29l per day and only 0.60l per hour!  BTW this is only about 4 US gallons per day so you wouldn't need a large RO unit to keep up with this!!!

If I only had one tank (or one connected system of tanks) I would run a system like this without doubt (though maybe with a different way of removing waste water with dirt from the filter).


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## gzylo (29 Dec 2009)

Hi Daniel

If you mean how I connect the pump to the sensor?
that`s a bit of a problem  as i`m not sure how it works for 100% I believe that wires in the sensor will have to be connected the mains of pumpp and with correct level it will allow current to go get to the pump and switch it on


I believe how it works but i`m not sure! 

With heater etc etc - that's not a problem as it all might be on a digital switch and be switched off for the period of water change - as of the filter I will be using spray bar and the tank is 350L so the water will not get to the bottom if it will I will switch of filter on the for the period of water change or will sort something out.

As of sump - the space is limited as its flat - i already have two fluval 405 and 80 plastic container under the tank so there is little I can do and thats why the water will be pumped out of the tank strait to waste pipe, i think the only manual think i will have to do it to break the "current" from that pipe so all the water wont go 


thanks
gzylo


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## Garuf (29 Dec 2009)

Could you not make something much less instrussive using a magnet and some reed switches? That thing really does look vast, what size tank will it be used in?


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## gzylo (29 Dec 2009)

Garuf said:
			
		

> Could you not make something much less instrussive using a magnet and some reed switches? That thing really does look vast, what size tank will it be used in?




Hi Grauf 

the switch takes around 5cm and and believe me you will not be able to find it in the tank  its 350L and it will be heavy planted. It already is but it will have a total make over  - thinking of journal too, depends on time.



I do not have a clue how reed switches work. No clue about electronics. So will stick with the switch its cheap enough. If it wont work i will think about your idea . Could you please explain to me how it works? 
does it opens circuit when magnet is around? or what?


Thanks
gzylo


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## Roy S (4 Jan 2010)

Garuf said:
			
		

> Could you not make something much less instrussive using a magnet and some reed switches? That thing really does look vast, what size tank will it be used in?



The float switch in the link IS a reed switch, the magnet used to close the switch contacts is in the float part.
This switch is pretty much identical to the ones used in Tunze osmolators for doing exactly what you describe, replacing evaporation water.

I would definately NOT wire this switch directly to a pump it wont handle the current OR the voltage, at best it could stick on resulting in the pump being driven all the time, or it could melt the wiring in the switch (sitting in your tank!) and possibly fry you or the tank occupants the first time there is a path to earth.
The maximum current it can handle is half an amp, a lot less than the current drawn by most pumps even small ones at startup, and the maximum voltage its rated for is 100 volts whereas our mains voltage is 240 volts!
The only way to use these switches with a pump, is to use it to trigger a relay at low voltage and current which in turn can handle the current and voltage the pump requires.
Maximum current and voltages are the manufacturers tested limits for safe and relaible operation, anything more than these and the switch risks either arcing across the contacts or insulation breakdown, or the contacts permanantly welding themselves closed.
They are great little switches for the job, just might be easier though to manually chuck water in unless you really need an automatic top up device?


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## paul.in.kendal (5 Jan 2010)

I've just set up a Tunze Osmolator in my c 200litre open-topped tank - just to offset evaporation.  It works great.  It has two switches, a float like the one mentioned in the first post of this thread, and an optical water level sensor.  The sensor switches the pump on and off, while the float is a back-up to override the pump if the level gets too high.  Water is drawn from a 13 litre container, which will not overflow the tank even if it is pumped dry. The pump also has a 10 minute timer cut-out, to guard against overflowing.

Tunze has upgraded the bracket for the two in-tank switches, which now sit side by side on a single magnetic clamp - very neat.

If I were you, I'd weigh up the downside of a possible flood against any benefits of auto water-changes very carefully indeed!


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## gzylo (6 Jan 2010)

paul.in.kendal said:
			
		

> I've just set up a Tunze Osmolator in my c 200litre open-topped tank - just to offset evaporation.  It works great.  It has two switches, a float like the one mentioned in the first post of this thread, and an optical water level sensor.  The sensor switches the pump on and off, while the float is a back-up to override the pump if the level gets too high.  Water is drawn from a 13 litre container, which will not overflow the tank even if it is pumped dry. The pump also has a 10 minute timer cut-out, to guard against overflowing.
> 
> Tunze has upgraded the bracket for the two in-tank switches, which now sit side by side on a single magnetic clamp - very neat.
> 
> If I were you, I'd weigh up the downside of a possible flood against any benefits of auto water-changes very carefully indeed!




Hello

quite good points !

Thanks


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