# Automatic water change system – DI/RO + tap water (lots of large pics)



## galabar (Oct 19, 2011)

Do you care about the chlorine and/or chloramine in the tap water?


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## proaudio55 (Oct 20, 2011)

According to my city's reporting, there's no chloramine added and the chlorine ranges from 0.04 PPM in the winter to 1.7 PPM during the summer. . . 

So my setup will put in around 4 gallons of RO/DI water and 1 gallon of tap water per day. At the max level of 1.7ppm into 72 gallons: that produces a chlorine concentration of about 23.6 parts per BILLION . . . I'm not going to worry about it.


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## galabar (Oct 19, 2011)

proaudio55 said:


> According to my city's reporting, there's no chloramine added and the chlorine ranges from 0.04 PPM in the winter to 1.7 PPM during the summer. . .
> 
> So my setup will put in 4 gallons of RO/DI water and 1 gallon of tap water per day. At the max level of 1.7ppm into 72 gallons: that produces a chlorine concentration of about 23.6 parts per BILLION . . . I'm not going to worry about it.


I'm not sure what concentration is dangerous. Here is one article claiming 0.003 ppm:

http://hendryutilities.com/docs/boxes/Chlorine_vs_Chloramine.htm



> Chlorine at high concentrations is toxic to fish; at lower concentrations, it stresses fish by damaging their gills. Concentrations of as little as 0.2-0.3 ppm kill most fish fairly rapidly. To prevent stress, concentrations as low as 0.003 ppm may be required.


You are talking about a chlorine concentration in your tank of up to 0.022 ppm. This assumes that all the chlorine added on each day leaves the system within 24 hours and does not accumulate. If the chlorine were to last for 72 hours, you are talking about something like 0.045 ppm.

I have no idea if that value is safe, but neither do you.  I would suggest more research.

Here is another article:

http://www.h2ou.com/h2wtrqual.htm



> Effects of chlorine on fish and aquatic life
> 
> The table shows how chlorine affects fish and aquatic organisms. It is important to realize chlorine becomes more toxic as the pH level of the water drops. And it becomes even more toxic when it is combined with other toxic substances such as cyanides, phenols and ammonia.
> 
> ...


Your value of possibly 0.045 ppm seems dangerous if the above values are to be believed.


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## proaudio55 (Oct 20, 2011)

http://books.google.com/books?id=Ja...nepage&q=mud plants +chlorine +reduce&f=false

This is a handbook for public water works; there's a discussion on page 458 that says chlorine is not effective when it comes in contact with "mud, decayed vegetation, or other suspended organic debris." Since my planted tank is loaded with that stuff, I'm going to settle my case that chlorine, at very low levels is not worth worrying about.


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## galabar (Oct 19, 2011)

proaudio55 said:


> http://books.google.com/books?id=Ja...nepage&q=mud plants +chlorine +reduce&f=false
> 
> This is a handbook for public water works; there's a discussion on page 458 that says chlorine is not effective when it comes in contact with "mud, decayed vegetation, or other suspended organic debris." Since my planted tank is loaded with that stuff, I'm going to settle my case that chlorine, at very low levels is not worth worrying about.


You really have no data to base that decision on. The chlorine will also come in contact with your fish's gills. The above charts claim that the level that will be in your tank is dangerous.

I'd suggest that you track it. There are simple test kits that will show you the level in your tank.

I wish you luck with your system. I'm sure it will be very cool when finished. However, the weight of evidence definitely seems to be against having a chlorine concentration as high as yours might be. You are thinking that the chlorine will be neutralized quickly in your tank and that it won't be a problem. That should be easy to test.

Again, good luck.

p.s. I hope your water is not muddy and full of decaying vegetable matter.


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## sick lid (Jan 13, 2008)

proaudio55 said:


> http://books.google.com/books?id=Ja...nepage&q=mud plants +chlorine +reduce&f=false
> 
> This is a handbook for public water works; there's a discussion on page 458 that says chlorine is not effective when it comes in contact with "mud, decayed vegetation, or other suspended organic debris." Since my planted tank is loaded with that stuff, I'm going to settle my case that chlorine, at very low levels is not worth worrying about.


Perhaps meaning that chlorine is not effective at killing what may be in the mud, decayed vegetation etc, not really where most of my fish swim, lol.
If your R/O puts out 50 to 100 GPD, and you're adding 5 GPD total to your tank, why are you mixing 20% tap water back in? (4g RO/ 1g tap= 80/20, not 75/25) Maybe I missed something in your post. btw, I'm here to question and learn, don't take this as criticism.


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## proaudio55 (Oct 20, 2011)

You're totally right on the math . . . my numbers are really 'squishy' because I just don't know what blend ratio I need to hit 5-7deg general hardness . . .

As for the issue of chlorine; I think that is a minor but valid concern. I'm going to tweak the plumbing setup slightly. Now all the water entering the tank will have passed through a carbon filter first and should be plenty safe.


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## plantbrain (Dec 15, 2003)

AC will certainly help and change them often.

I'd add a float switch in tank or in a sump. I've done this set up for 2 client's. 
The sump has an overflow, so the water goes out there instead of the tank, keeps more junk out of the tank. I have an over flow in the tank also JUST in case something clogs also.


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## proaudio55 (Oct 20, 2011)

And my first box showed up today. No word on the second rotameter. . . The pictures and updates are in the original thread.


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## Bettatail (Feb 12, 2009)

plantbrain said:


> AC will certainly help and change them often.
> 
> I'd add a float switch in tank or in a sump. I've done this set up for 2 client's.
> The sump has an overflow, so the water goes out there instead of the tank, keeps more junk out of the tank. I have an over flow in the tank also JUST in case something clogs also.


+1, wire the float switch to control the solenoid, instead of on a timer.

use the timer on a pump that drain the water out of the sump or main tank, of course, the pump has another float switch once the desire drain level reach, the pump will stop.


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## proaudio55 (Oct 20, 2011)

Ok, I couldn't wait, I hooked-up my rig and worked around the missing component. I got it set to 7deg general hardness by running the RO circuit at 100% and throttling the tap water to 1.5 gallons per hour. I tested for chlorine and that is at 0.0 PPM (pictures in first post). I'm thrilled!! Everything ran for about 3 hours this evening: it worked like a charm! Even the little bit of surface scum in the tank all went down the drain. . . . to quote charlie: *"Duh, WINNING"* 

The only discovery I made was that I'll need to upgrade my heater. I was hoping my 300w would be able to keep up with the inflow of 50deg water, it mostly did, but could use a little help. Going forward, the water change timer is programmed to run 1 hour every day between 7-8pm. If there's a problem (flooding) I'm most likely going to hear/ notice it. I'm also going to dial back the hardness a little and try to hit 5dGH instead of 7. Regardless, it's a huge improvement over the 16+dGH water that I would ordinarily use.


About using a float valve / automatic drain . . . that was the whole point of this build. I wanted to do an automatic water change system without using those.  I really like things that are "irreducibly complex;" of all the water changing systems, I assert mine is the most simple, elegant, and reliable! 

Now as per TPT.net protocol: Everyone will pile on with how I'm an idiot and they have a better system  j/k


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## proaudio55 (Oct 20, 2011)

*It is finished . . .*

Moved update to post #1


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## perezdr (Jan 25, 2012)

Where is the original thread with the final pictures??? I don't find it! Thanks!


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## proaudio55 (Oct 20, 2011)

perezdr said:


> Where is the original thread with the final pictures??? I don't find it! Thanks!


It's picture #2 on the very first thread  Re-posted here, this is what the final package looks like. I only omitted the external plumbing: 1 line going to the tank and 1 line going to the drain. The water supply line is visible on the front right. Then it hangs on the wall via the bracket on top.


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## proaudio55 (Oct 20, 2011)

*Update*

Moved update to post #1.


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## proaudio55 (Oct 20, 2011)

moved update to post #1


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## jdmstop (Aug 24, 2007)

so a full RO DI water change with tap water is better than just the RO DI alone? I do about 30% water change weekly.


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## proaudio55 (Oct 20, 2011)

jdmstop said:


> so a full RO DI water change with tap water is better than just the RO DI alone? I do about 30% water change weekly.


The discussions can be found on other threads, but plants and fish both need some calcium and magnesium in the water. If you use 100% RO water, your critters will be stressed (and possibly killed) from lack of minerals.

Most fish are comfortable with 3-10 degrees general hardness. (with the obvious exception of rift lake cichlids, that swim in liquid rock). Do a little research and find out what experts say for your particular critters.

R.O. top-off is fine, if you're just replacing evaporated water, but IMHO water changes should always be done with blended water.


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## plantbrain (Dec 15, 2003)

proaudio55 said:


> Now as per TPT.net protocol: Everyone will pile on with how I'm an idiot and they have a better system  j/k


Well, one wet floor later...........is not the best way to learn. 
Just make sure/certain nothing can get clog those overflow drain, if so, things will not end well, I can see a few good sized leaves doing that.


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## fauxjargon (Oct 23, 2010)

proaudio55 said:


> http://books.google.com/books?id=Ja...nepage&q=mud plants +chlorine +reduce&f=false
> 
> This is a handbook for public water works; there's a discussion on page 458 that says chlorine is not effective when it comes in contact with "mud, decayed vegetation, or other suspended organic debris." Since my planted tank is loaded with that stuff, I'm going to settle my case that chlorine, at very low levels is not worth worrying about.


Yes - chlorine reacts with the organic gunk in your tank just as readily as it reacts with your fish. In trace doses it is not an issue.


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## DKShrimporium (Nov 23, 2004)

Love the ideas, but rather costly to implement. (I'm guilty of worse, much worse...) Great thread! Two observations:


It looks to me that the blend ratio is predicated on constant input pressure from both RO and tap lines. RO line is "wide open" and tap is controlled by a physical valve orifice size, right? So as your RO membrane ages and your RO output is reduced, your blend ratio will alter over time slightly, right? And in my case I'm on a well pump so my tap water pressure fluctuates with the bladder. Just some points to think about for others considering this setup.
Your water change is not actually as much as you think, because the overflow water exiting the tank is not pure used water but a blend of new and used water.


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## proaudio55 (Oct 20, 2011)

Update moved to post #1


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## Pickled_Herring (Jul 26, 2010)

Hey great job. This is something I've thought about incorporating on all my tanks. I plan on including an emergency overflow down to a drain at the top of the tanks. Also I will include an alarm switch in the drain and shut off switch on the input side. Where I live the water dept is chloromine crazy. Therefore I will also need a tank where I can pretreat the water by adding sodium thiosulphate and additional filtering through carbon. I'm a veteran of many water spills due to blocked drains so that's my concern with flooding. As Tom said those big leaves are killer on house floors.


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