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Automated water changer


Lynaea

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This is based on the Reef-Float:

http://www.reefloat.com/awc31.html

 

I can't afford the exchange rate plus the shipping from the UK so I decided to build my own less advanced version.

 

Essentially this is an airtight container with an inlet and outlet tube and a pump. Both tubes are placed in the aquarium and when the pump is started the fresh water flows into the aquarium and old water is drawn out. Of course because this is a closed system the water eventually mixes. After an hour or so the container now containing mixed (but mostly old) water is disconnected and the water discarded. If you put 20% of the tank volume in the container then what is discarded is essentially 80% old water.

 

Obviously this is not exactly the same as removing 20% of the water and replacing it with an equal volume of fresh but it is fairly close and, I would expect, less stressful for the inhabitants, especially for a small tank.

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Supplies:

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--Vittles Vault, this is the 25 pound size, holds about 6.5 gallons per manufacturer.

--2 Uniseals, 1/2 inch size (these are designed for PVC so sizing for flexible tubing is based on ID of the Uniseal, see manufacturer info)

--5/8" ID / 7/8" OD tubing

--Cobalt in-line pump, 240 gph

--timer, to delay the flow so all the new water doesn't mix in at once.

--flexible inlet and outlet spouts, ** these leaked so I couldn't use them**

--drill and hole borer of appropriate size, in this case 1 1/4"

--dremel or sand paper

--Pipe tape

--silicone

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This is after the holes were drilled, Uniseals and tubing inserted. Bulkheads could be used instead but I don't have experience with those so this seemed easier.

 

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Outlet tube with pump at bottom, inlet at top.

 

The Uniseal's fit fairly tightly into the holes and were watertight but there was some give. I did a trial run at this point but the flexible spouts leaked at multiple points. Even after using just the tubing there seemed to be air leakage as the aquarium water slowly rose over the 30 minutes or so I tested (I used an extra tank for this).

 

At this point I decided the Uniseal's were not airtight so I siliconed them under the black outer lip and around the outer edge of that lip and let cure for 48 hours.

 

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When I tested at this point I realized one of the tube connections to the pump had a slow leak, one side has ribs so the screw down doesn't work as well on that side. I used pipe tape instead.

 

I also devised a new inlet from some adaptors and extra pieces I had from other filters. The outlet is just the tube at this point.

 

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I also attached a sponge filter to the outlet tube inside the container with the thought that detritus will be drawn into the container but will not recycle back to the tank.

 

This time when I tested the water in the tank lowered slightly each time the pump went off. My thought is that I left too much head space in the container and that the water was compressing the air and filling the container a bit more each go round.

 

I have now filled the container with RO/DI and salt to within 1/2" of the top and am mixing it. This is easily accomplished by inserting the end of the outlet tube into the container and plugging in the pump, the water then just recirculates through the tubing.

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The original this is based on uses a controller/timer to turn the pump on and off several times throughout the hour or so of mixing time. I did some math and decided to do 1 minute on, 10 minutes off three times, then I extended both the on & off times each cycle until the last on is about 30 minutes.

 

This should give me a good mix and also give ample time for it to filter out detritus. This could be run without a timer but all the new water would mix in within 2-3 minutes, this would still be less drastic a change then a standard water change but more than I would like.

 

Hopefully I'll have time to run it on my tank tomorrow, the only chance of failure I see is if the lid is not truly air/water tight as stated and the water is able to overfill the container, fingers crossed it works as expected.

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I know Gordon who makes the AWC.

He clearly spent ages developing debugging and getting everything working perfectly with his great product. Even then he is continually releasing improvements (like his pre filter system)

 

I would be very cautious you do not end up flooding your room. He had to put hundreds of hours into developing his clever design into a finished product that is 100% safe to use.

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I know Gordon who makes the AWC.

He clearly spent ages developing debugging and getting everything working perfectly with his great product. Even then he is continually releasing improvements (like his pre filter system)

 

I would be very cautious you do not end up flooding your room. He had to put hundreds of hours into developing his clever design into a finished product that is 100% safe to use.

 

I agree the Reef-Float looks extremely well thought out and if it weren't for the cost I would have just purchased that instead. If this doesn't work then maybe I still will. If you think I should remove the brand name I can do that, not sure if I'm giving them a plug or ripping them off.

 

I will definitely be monitoring it closely the first several uses.

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Why mix dirty water with clean water in the first place, and then pump it back into the tank?

 

Seems silly.

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Why mix dirty water with clean water in the first place, and then pump it back into the tank?

Seems silly.

 

I believe this is answered better on the site linked above and some of the threads listed there. Essentially it adds a volume of water to the system, mixes it and then removes a large portion of old water as well as suspended sediment and detritus. See my results below.

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Why mix dirty water with clean water in the first place, and then pump it back into the tank?

Seems silly.

 

I agree. So basically it's like doing a water change, but you dump the clean water in first before removing the old. I don't feel like doing math right now but it seems like the wc would be about half as effective as a normal one. Might be good if you did it daily.

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Success! (For the most part) :)

 

Okay, the Vittles Vault lid is not water tight, however, when it got too full it just dripped a bit. It only back siphons from the aquarium when the pump is off so when I noticed this I turned the pump on and pulled the inlet tube out of the aquarium long enough to get an air pocket formed again. After that I left the unit running for an hour with no overfilling or leaking.

 

There are several pluses I see:

1) Adding 20% or so volume of new water to an existing system and letting it mix is less stressful to livestock than removing 20% of the used water and replacing it with fresh. This would be especially true if water changes are done infrequently or when there is a difference in temperature or parameters between the new and old water, when changing salt types/brands for instance.

 

2) The water level also isn't lowered this way, someone with a pico could easily do a very large % change without exposing rock and corals to air.

 

3) A LOT of detritus and suspended particles can be removed this way and it is all removed from the system rather than sitting in a filter until the next change. I ran the pump for an hour and spent a good bit of that time stirring up junk from the sand bed and rocks, not all of it made it into the container but a whole lot did. My water is considerably cleaner after this one water change than it was after doing three similar volume changes in a week. This is mostly due to the time it is left running, there is only so much detritus that can be sucked out in the time it takes to fill a 5 gallon bucket. For the record I used a Filter-max sponge prefilter, this is the original fine pore sponge not the more porous 'pro' version.

 

4) With the right set up it could be set up and left mostly unattended to run for an hour +, then you just disconnect it and drain the water. My tank is directly in front of my kitchen sink so when I was done I just unplugged the pump, removed both tubes from my tank and put the outlet tube into the sink, it drained most of the water without my even opening the lid. For my next few changes I will need to dislodge the over-abundance of crap I have settled in my tank, but once I get it under control I will be able to start it, give the rocks and sand some squirts and let it go.

 

It still needs some tweaking; definitely need a way to secure the tubes to the tank, I also think a check valve on the outlet tube would help with the back siphoning when the pump is off. For now I think I'm going to adjust the timer to 1 minute on, 1 minute off for the first 6 minutes and then just let it run for an hour or so to mix and collect detritus.

 

So far I'm quite happy with this but obviously it will not work for everyone.

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I agree. So basically it's like doing a water change, but you dump the clean water in first before removing the old. I don't feel like doing math right now but it seems like the wc would be about half as effective as a normal one. Might be good if you did it daily.

 

You are removing some of the "fresh" water with the water change. This means that any replenishment from the new water is diluted and partially taken out (less effective), the amount of waste product in the old water diluted with the greater volume and the amount that you take out is less (less effective). On the other hand, since it is a gradual mix of new water with the old water over an hour to three hours, it may be less of a shock to the tank inhabitants than pulling out the old and dumping in the new all of a sudden, it may be easier and more convenient leading to more frequent or larger water changes to offset the diminished change.

 

The effectiveness of the water change is greater with smaller percentages of water change. If you have a 5 gallon nano tank and do a 5 gallon water change, then you will be left with 2.5 gallons of old water and 2.5 gallons of new water (50% effective rather than 100% water change). If you are changing 5 gallons in a 100 gallon tank, instead of a 5% water change, you end up doing a 4.76% water change. Depending on the individual, the convenience (and lower shock to the tank) may outweigh the loss of 0.24 gallons of fresh water in the 100 gallon tank. The 50% loss of effectiveness for a 5 gallon tank would be more difficult to swallow for most people...

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What shock is there from new salt water?

 

If the temp and SG is the same, whats in the new salt water that "shocks" anything in your tank?

 

Is there any science or data) even an article) to back up this idea that corals or fish are shocked by clean new salt water?

 

 

 

Even an RKL with a switch module can be turned into an automatic water changer. A real one that pumps out dirty water then pumps in clean water. The logic in programming it is not that hard if you wanted to do it.

 

The idea of pumping in new clean water then pumping it out is a waste, thats dumber than pumping dirty water back in after youve pumped it out. Watching the video of that site, his invention seems to do both.

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What shock is there from new salt water?

If the temp and SG is the same, whats in the new salt water that "shocks" anything in your tank?

Is there any science or data) even an article) to back up this idea that corals or fish are shocked by clean new salt water?

I have been on the freshwater side of this hobby for over a decade and have read numerous posts from people who killed their fish by changing the water, sure some of them were ignorant of chlorine, etc. but my fish have had obvious responses to a water change (good and bad), especially if it hasn't been done for awhile. I would expect that saltwater is the same, the whole point of using more than just NaCl mixed with water is that tank inhabitants actually use calcium, magnesium, etc, I would expect a sudden change in mineral concentrations, let alone nitrogen levels, to be a stressor regardless of how positive the change is. Change is change and it stresses things out, whether you notice or not.

 

I can also say that last evening was the first water change I've done on this tank where some of the fish came out to see what I was doing and the majority of the corals stayed open for the duration. And as stated above, my water looks considerably clearer and cleaner.

 

It was nice to feel like I was cleaning everything up without all the fish freaking out like they often do when I significantly lower the water level in my FW tanks while changing and cleaning them.

 

That said, to each his own.

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That said, to each his own.

 

I agree. I have my own anectdotes as well. Opposite results and reactions that you note.

 

That's why I asked if anyone had any science or data to back up the claim that clean salt water "shocks" livestock.

 

My experience is the opposite. If anything shocks livestock its a drastic change in temperature, I have noted this. I have never seen a bad reaction due to clean water.

 

So, does anyone have any science?

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an easy one... 10% water change on 200 liters is 20 liters, using this system you do a water change that is 9% instead of 10%. The returns on small frequent water changes are very efficient. Now if you had a 20 liter system and did a 20 liter water change using this system instead of a 100% water change you only get a 90% water change. The system works quite well.

 

so if you had 10 ppm nitrate on a 200 liter system and did the 20 liter water change regularly you would reduce nitrates to 9ppm. using reefloat or this diy would get it to 9.1ppm. I personally think its a pretty sick little invention.

 

as for too frequent of water changes, i don't buy it. Its only a shock to the system if you do them irratically going from 5ppm phosphates to 0 in an instant probably isnt a good idea for the coral.

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As a heads up, just in case anyone else actually tries this; the Vittles Vault container will NOT work. The first use went okay but apparently stressed the plastic enough that the lid would not seal properly the second use. I was able to use it by pressing down on the lid, otherwise I could hear air leaking, but I won't be risking a third try.

 

I'm going to look into other containers versus purchasing the Nano version of the real thing.

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Yeh there is a reason I havn't tried my own diy version of one to cut back on the insane shipping cost from europe. 5 gallon buckets for me for now.

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  • 3 weeks later...

If you could find something to use as a bladder inside the airtight container you could make a system that still only uses one pump and could do a water change closer to those performed normally(no mixing of new water and old water in the water change unit). Maybe an old salt bucket with a tight sealing lid with an O-ring would work?

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If you could find something to use as a bladder inside the airtight container you could make a system that still only uses one pump and could do a water change closer to those performed normally(no mixing of new water and old water in the water change unit). Maybe an old salt bucket with a tight sealing lid with an O-ring would work?

google 5 gallon bucket canister filter. They have been made but its quite difficult to get that seal air tight.

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Why the need for an airtight container?

 

Seems straightforward enough.

 

Pump out X gallons.

 

Then pump in X gallons.

 

Seems super simple.

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