Reef Angel Forum

any ideas on an auto water change..

a container of salt water would be neccesary... a pump for going in the tank, a pump removing water from the tank.. float switches..

i would love to change 2 gallons of water a day.. well actually one gallon a day, then biweekly siphon the sand bed and give everything a good cleaning...

so a pump to run a set amount of time, or until a switch was activated, then another pump coming on refilling to the normal ato switch was activated once a day would be cool...

anyone trie

You can do that
Now the really cool thing is this new module I'm working on that would make it really simple
I have a water level module being tested as we speak
It has about 16 inches of sensing range.
It operates by measuring the pressure caused by water being displaced inside a 1/2" PVC pipe.
With this module you could do something like stop ATO, drain 2" of water and refill 2". Re-enable ATO when done. Pretty nice huh?

I'd be all over that!

That is really interesting. I'm obviously going to need a bigger tank so that I have a bigger stand under it for all the cool stuff you keep adding!

want!

Hi Guys, I have been thinking about this too, and have a very easy suggestion that only requires one pump and one water container.

First, the strange thing here is that you will only need 1 container to do your water change - basically you have a container with your fresh salt water in it and that container will also hold your waste salt water.

The theory (and practice) is quite straightforward.

For ease of numbers, lets imagine you have a 500 litre tank and you want to do a 10% water change - i.e. 50 litres.

Basically you connect you water container with 50 litres of fresh salt water to your tank of 500 litres and you constantly take water from you fresh water container and add to your tank at the same time that you take the same volume back to your fresh salt water container. Effectively what you have done is now increase your tank volume to 550 litres. You let this exchange take place over however long you want and depending how quickly you do this, you will eventually end up with a homogenous saltwater mix.

You then, simply disconnect your water change tubes from the tank and take away 50 litres. You have now effectively done a 9% water change - you have removed 50 litres from 550 litres, which is just over 9%, and your water level is completely unchanged!

So, how do you get away with one pump?

Your fresh salt water container needs to be capable of being completely sealed i.e. a container with a screw cap lid with a seal.

You will then need to do some things with this container!

1. In its simplest form, you will need to fit 2 tubes into this container - one for water out and one for water in (diameter depending on the pump you use). The tubes where they exit the container will need to be completely sealed and airtight - you can use electrical gland nuts for this purpose.

One of these tubes will connect to your pump which then connects to your tank (or sump) - these connections again need to be airtight.

The other tube is your return line and simply connects to your tank or sump.

Operation:
Your container needs to be filled completely to the top with your fresh salt water - no air gap (or as small a gap as possible). You put on the lid and tighten so now the water change container is completely airtight.

You then put your pump tube into your tank or sump and also your return tube and then start your pump!!

What will happen is, that as your fresh salt water is pumped into your tank, the return tube will remove water (due to being a sealed system) from the tank AT EXACTLY the same rate, keeping your water level constant.

This does actually work, but it is critical that all joint are airtight to maintain the seal.

So there you have it, a simply way to effect an auto water change with 1 pump and 1 container!!!

The auto water change can be further improved by putting the pump inside the container (electrical line out will of course need to be sealed) and adding a on/off tap on the flow and return line. Adding the pump inside the container then enable the pump to be used to mix your next batch of water!!

You can use your reef angel to control this to change the water over however long you want!

For example: Lets say you want to do a 50 litres water change per week, then you need to change a bit over 7 litres per day - lets say 8 litres. If you measure the flow rate of your pump, you can estimate the running time needed for your pump to pump 8 litres and then simply set your relay box using the wizard to run for x number of minutes per day!!

Once a week, take off the water container, empty it, make up fresh salt water connect it, and your good to go again!!

Patent it quick!!!
Cool idea indeed

rimai wrote:Patent it quick!!!
Cool idea indeed

I will let you commercialise this one roberto!!!

Very easy to do, and a must have!!

All I want is a free expansion unit and relay box for the idea LOL!!

We are talking about displacement of air right? AKA suction? The idea is great! I would however use two tubs connected via a air tight line..this would allow the suction to build in the second (dirty water collection) tub while pumping 100% fresh salt water out of the other...the dirty water collection tub could then also have a ball-valve for emptying the dirty water to whereever you would like it to go...

same concept..just a little tweek to not allow dirty water to cycle with fresh.

I think his idea is to mix them together and that's why just one container and I think is displacement of water and not air.

Negative air pressure creates suction. So that's why I'm curious what he means. Also mixing old with fresh would mean it wouldn't be 100% clean water? I guess I'm confused

DrewPalmer04 wrote:We are talking about displacement of air right? AKA suction? The idea is great! I would however use two tubs connected via a air tight line..this would allow the suction to build in the second (dirty water collection) tub while pumping 100% fresh salt water out of the other...the dirty water collection tub could then also have a ball-valve for emptying the dirty water to whereever you would like it to go...

same concept..just a little tweek to not allow dirty water to cycle with fresh.

Hi, no offence, but this definitely will not work.

Reason is that you will end up with a different volume removed than added because of the ability to compress/expand air readily i.e. water change water will be added to your tank for a while without liquid been drawn out until such time as a sufficient vacuum is formed - so more water will be added than removed.

For example - if you take a bicycle pump, draw out the plunger and hold your finger over the end, you will easily be able to compress the air - because air is easily expanded or compressed. If you did the same and filled the pump with water, you would not be able to compress the water at all, because liquids cannot easily be expanded or compressed.

The model I mentioned has no air in the system (or very, very little) and thus what volume is dispensed is also withdrawn, maintaining the same water level.

Granted with the system I mentioned, if you are trying to achieve a 10% water change, what you actually achieve is a 9% water change. If the 10% or higher is critical of you, you just need a bigger vessel to accommodate a larger volume and then you will be able to achieve a 10% or greater water change in absolute terms.

Also, with my method, because of the mixing of the waste water with clean water, temperature differentials are minimised, and providing there is not too big a difference between the tank and water change temperatures, there is no need to heat the water change water.

Hope this makes some sense!!

DrewPalmer04 wrote:We are talking about displacement of air right? AKA suction? The idea is great! I would however use two tubs connected via a air tight line..this would allow the suction to build in the second (dirty water collection) tub while pumping 100% fresh salt water out of the other...the dirty water collection tub could then also have a ball-valve for emptying the dirty water to whereever you would like it to go...

same concept..just a little tweek to not allow dirty water to cycle with fresh.

Hi, no offence, but this definitely will not work.

Reason is that you will end up with a different volume removed than added because of the ability to compress/expand air readily i.e. water change water will be added to your tank for a while without liquid been drawn out until such time as a sufficient vacuum is formed - so more water will be added than removed.

For example - if you take a bicycle pump, draw out the plunger and hold your finger over the end, you will easily be able to compress the air - because air is easily expanded or compressed. If you did the same and filled the pump with water, you would not be able to compress the water at all, because liquids cannot easily be expanded or compressed.

The model I mentioned has no air in the system (or very, very little) and thus what volume is dispensed is also withdrawn, maintaining the same water level.

Granted with the system I mentioned, if you are trying to achieve a 10% water change, what you actually achieve is a 9% water change. If the 10% or higher is critical to you, you just need a bigger vessel to accommodate a larger volume and then you will be able to achieve a 10% or greater water change in absolute terms.

Also, with my method, because of the mixing of the waste water with clean water, temperature differentials are minimised, and providing there is not too big a difference between the tank and water change temperatures, there is no need to heat the water change water.

Hope this makes some sense!!

i think i know an alternative way, correct me if i am wrong. why not use the double dosing pump. put one pump set up to suck from the aquarium and one to suck from a saltwater jug. the dossers are very reliable and could be set up with a timer to set how many gallons to change out per day using the .75ml/sec flow rate. just set it up so it removes 2 gallons while the ATO is off and then add it right after time settings for that would be for example:

ATO off @ 1am
Pump 1 (remover) on @ 1:30am off @ 4:30am (2gallons)
Pump 2 (replenish) on @ 5am off @ 8am (2 gallons)


I think I would only do it with a salinity probe to make sure you maintain a tight salinity reading. I would also use two water sensors one in the waste water tank to keep from accidental overflow as well as one at the top of your sump for the same reason. to me this would be the safest way to do a automatic water change.

I may be a little over worried but I am a koi pond professional and i have literally seen tens of thousands of dollars in dead fish from a faulty piece of equipment from a automated water changer. nothings will ruin your day more! so think this stuff out well before you do it!!

So any code for the original poster's idea?

I think auto water change just got a lot more easy with the new water level sensor!!

Did you get one? I am away from home for work, but will be working on it when I get back. Only thing I debate about is whether to go the wet skim route or pump out.