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

[proaudio55]

My apologies if this was designed by someone else, I came up with the concept independently. I don’t mean to reinvent the wheel, but I haven’t seen this setup before.

Overview: I’m looking to setup a system to do water changes automatically.
~It needs to be reliable, because if the house floods, my wife will kill me.
~I don’t trust float switches / float valves and don’t want that clutter on my tank.
~I don’t trust automatic drain valves: if it gets stuck with a dead fish / weeds / fails open . . .the tank will drain without my knowledge.
~I have very hard water (16-20 degrees general hardness) and want the critters to be comfortable in soft water.

So here’s what I'm putting together:
This is a trickle water-change setup that will blend DI/RO water with tap water. It works without float switches or float valves and is pretty idiot-proof. Because of the solenoid valve placement, there’s no risk of feeding hard water backwards through the RO unit. It should be very reliable because the only vulnerability is the overflow; since the water is trickling in at less than 5 gallons per hour, I’m not too concerned about flooding the house. As for my approach, I argue doing a small water change every day is better for the critters than one big 50% change once a week.


Parts list:
Drilled aquarium with overflow and permanently plumbed to a drain (sewer, garden, etc)
RO/DI unit: 50 to 100 gallons per day output
1/4" polyethylene tubing
Dwyer instruments flow meter: VFB-80-SSV (rotameter with valve to throttle tap water)
Dwyer instruments flow meter: VFB-80-SS (wide open rotameter for RO/DI water)
Dwyer instruments solenoid valve: SBSV-S1F1 (Normally Closed, 120v AC, 188PSI WOG rated)
Miscellaneous 1/4” fittings


http://www.plantedtank.net/forums/pH...er_finalcc.jpg

Here is the final product:


Update: 1/25/12
I just ordered my parts today . . . one of them is a “special order” item ++sigh++ hopefully it’ll show up in a few weeks. Till then I need to hook into my sewer line.

Update: 1/27/12
After a bit of discussion on the board, I'm changing where I draw my tap water from. The hardwater tap now is being taken off just in front of the RO membrane. All other aspects of my setup remain unchanged
Here was the original idea:
http://www.plantedtank.net/forums/pH..._changingc.jpg
Changed to:
http://www.plantedtank.net/forums/pH..._filter_2c.jpg

Update 1/28/12
I have the drain all plumbed in and its working exactly as planed. I put a loop in the drain hose which will serve as a 'trap' and prevent sewer gasses from coming back up the overflow. My only negative discovery is that the manual drain valve is extremely loud!! The gurgling can be heard though out the house. However, the overflow is silent and I can deal with a little noise for the few times I actually need to drain off a large volume of water.

This is the only valve I am installing on the drain side. All parts here are 3/4" (hose barbs, valve, etc)


Here's the aquarium's plumbing


Update 1/30/12
My first box showed up. I got the solenoid valve and rotameter with needle valve.



The little bullet shaped piece of stainless steel is the float that gets pushed up by the flowing water. That indicates how much liquid is passing by.



This is a piece of scrap aluminum we had laying around at work. I cut and bent this into a bracket to hold the rotameters



Here the aluminum is bent into my "control panel"


Update 2/1/2012
I got the hardwired timer purchased and installed. The whole build is done, except for the RO rotameter.


Update 2/2/2012
I couldn't wait for my parts to show up so I jerry-rigged it around the missing component. I tested for chlorine break-through and even with 2+ year old carbon filters, I'm BDL (below detection limit) on chlorine!!


Update 2/3/2012
The timer is acting up: it turned on at 7pm as it should but was still running at 10pm (it was supposed to shut off at 8pm). . . I did a little reprogramming and it should be working correctly now. And according to Dwyer, my other box shipped out yesterday. Monday I should be be able to finish this project.

Update 2/6/2012
I got my last component in and everything is now assembled. I "fired it up" this afternoon and everything is working perfectly!!

I didn't discover any design flaws and I don't have any regrets. The only suggestion I have someone wanting to copy this, go for the 75-100 gallon per day RO filter. A higher output filter will run the rotameter more in the center of the range.

Good luck to all of you and be sure to post your DIY's for the rest of us to admire / learn from / laugh at!!


This is the back side of the rotameter "control panel." I just used plastic quick connect fittings. Homedepot had exactly what I needed!?!!


Here is the final assembly with important parts labeled


And this is the system when it is running. When I snapped this pic I was still playing with the flow rates.


Now that the whole project is done, my only suggestion to those looking to copy this is: Go with a 75-100 gallon per day RO/DI filter. My 50 GPD rig barely puts out enough flow to register on the rotameter. Not a biggie. Total price on this thing in 2012 dollars is about $400-500.
$120 for the RO filter
$200 for the rotameters and control valve
$30 for the timer / electrical components
$50 for the tubing, plumbing fittings, and drain parts
$50 for a diamond hole saw and bulk head fitting for the aquarium glass
$50 for shipping, taxes, misc expenses, screw-ups

UPDATE 2/21/2012
I'm now almost a month into this automatic water change system. The water chemistry changes are quite dramatic! One area of huge improvement is on phosphates! Up until now, every time I did the test, it was "PEGGED" off the chart at 10+++ PPM. The test would turn ink blue in seconds . . . I didn't need to wait 3 minutes to know I had tons of it. (I think that problem was from overdosing 7.0 Ph buffer)

As of today, I'm testing at:
0 ppm PO4.
0 ppm Nitrate
0.25ppm ammonia (I'm suspicious of this, I don't think that's possible with my moderately-to-heavily planted tank.)

The tank is heavily fertilized with root tabs and all my plants are root feeders. Even so, the plant growth has slowed way down. It seems everything was thriving on my neglect! ++sigh++ we'll see how ambitious I am, but I may end up doing a quasi Estimative Indexing fert schedule.


http://www.plantedtank.net/forums/pH...m_2-17-12c.jpg


Today things are looking very healthy. If you look really close, you can see the overflow in the top left corner. [The arrows are for an unrelated thread, but they point out my 3 awesome Nymphoides Aquatica (banana plants)].

http://www.plantedtank.net/forums/pH..._banana_2c.jpg

Update 4/14/2012
Here's a little update...
My setup has been running FLAWLESSLY for over 2 months now! The fish have never been healthier, the water chemistry has never been better and honestly I don't know what to do with myself. In the past I was always chasing after the water parameters because something was perpetually out-of-whack. I was always fighting with the ph, or the nitrates, or something . . . but now, it just runs on auto pilot.

If you're even remotely interested in doing an automatic water change system, my setup is the way to go!!!! Very simple, very reliable, with fantastic results! As long as I'm into freshwater fish keeping, I will be using this system on every tank.

Today I checked the chemistry and thought I'd post the results:
Feed water from system:
0.0ppm Cl
5 deg general hardness

Tank water:
0 ppm nitrate
2ppm phosphate (From adding 7.0 ph buffer)
6.6 ph
0.1 ppm(?) amonia
9 deg General hardness


http://www.plantedtank.net/forums/pH...m_4-14-12c.jpg


About 1.6 gph of RO water + 1.1 GPH of tap water = 2.7 gph and it runs 1 hour daily.
2.7 gallons * 7 days a week = 18.9 gallons a week.
The tank is 72 gallons, so that means I'm doing 26.3% water change every week. That seems to be just perfect for my stocking of plants & fish.

http://www.plantedtank.net/forums/pH...4-14-2012c.jpg


Sorry for the window reflection. Bow fronts tend to reflect EVERYTHING!

http://www.plantedtank.net/forums/pH...pril_2012c.jpg


Here's a shot of my surface scum on the water. BOOM!! Just kidding, NONE!!

http://www.plantedtank.net/forums/pH...ater_scumc.jpg


Here's an artsy-fartsy shot of my nymphoides aquatica pearling

http://www.plantedtank.net/forums/pH...pril_2012c.jpg

Update 6/7/2012

Originally Posted by DKShrimporium

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

1. 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.
2. 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.

Yepper on #1, the RO filter output will definitively slow down with time. I check for Chlorine breakthrough and hardness monthly or so, so far it has stayed fairly stable.

And yepper on #2. Below is a picture of input and output. I'm filling at about 175ml per minute, 45" away. So the new water is thoroughly mixed by the time it gets to the far side. ++shrug++ I'm ok with the fresh water loss because I avoid needing a drain timer and a drain solenoid valve.


http://www.plantedtank.net/forums/pH...overview1c.jpg

This was posted for a different thread, but it's a detail of the overflow; The murkeyness is from installing a new canister filter. You're looking at a bacteria bloom here.

http://www.plantedtank.net/forums/pH...ow_detailc.jpg

Same thread, detail view of the waste water draining via surface tension

http://www.plantedtank.net/forums/pH..._of_waterc.jpg

[galabar]

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

[proaudio55]

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.

[galabar]

Originally Posted by proaudio55

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/boxe...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.

Phenols are organic chemicals produced when coal and wood are distilled and when oil is refined. Phenols are found in a number of products—from organic wastes to sheep dip. Although phenols are very toxic, dilute solutions of a phenol (carbolic acid) are used as a disinfectant.

Table 3. Effects of chlorine on fish and aquatic organisms
Total chlorine (in mg/L) Effect
0.006 Kills trout fry in two days.
0.01 Recommended maximum for all fish and aquatic life.
0.01 Kills Chinook Salmon and Coho Salmon.
0.01-0.05 Oysters have difficulty pumping water through their bodies.
0.02 Maximum Brook and Brown Trout can withstand.
0.05 Maximum amount that can be tolerated by young Pacific Salmon in the ocean.
0.1 Kills most marine plankton.
0.25 Only the hardiest fish can survive.
0.37 Maximum fish can tolerate.
1.0 Kills oysters.

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

[proaudio55]

http://books.google.com/books?id=Ja2...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.

[galabar]

Originally Posted by proaudio55

http://books.google.com/books?id=Ja2...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.

[sick lid]

Originally Posted by proaudio55

http://books.google.com/books?id=Ja2...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.

[proaudio55]

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.

[plantbrain]

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.

[proaudio55]

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

[Bettatail]

Originally Posted by plantbrain

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.

[proaudio55]

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 :-P j/k

[proaudio55]

Moved update to post #1

[perezdr]

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

[proaudio55]

Originally Posted by perezdr

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.