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View Full Version : Any ideas for alternative for RO water?


kelp47
10/02/2012, 11:44 AM
I'm building my equipment list for my new 75 gal reef setup, and I'm currently trying to choose my water filtering method. I was looking at RODI filters, but I really don't like the idea of all the waste water put out by the RO section of the filter. I've read the ideas about reusing the waste water, but I don't think this is going to work for me. Is anyone else running just a DI filter with success? Is there another filtering method that can be paired with DI, other than RO, to produce high quality water?

alton
10/02/2012, 12:00 PM
The waste water from RO systems taste better than my tap, work great on watering my trees and my wifes plants. With a 75 gallon tank and 5 gallon a week water changes you are looking at wasting 1040 gallons in a year or just water your trees, grass, give your dog a bath. There is a number of ways not to waste it.

kelp47
10/02/2012, 07:28 PM
I really don't think I can use all that waste water. Plus, I would probably have a problem with the RO filter because I have pretty low water pressure. I'm looking for an alternative, not ways to use waste water. But thanks for the suggestion.

Crusty Old Shellback
10/03/2012, 07:21 AM
For me, I use my RO just as an ATO.

When I go to make water for mixing salt for water changes, I bypass the RO membrane and just use the 5 micron filter and 2 micron carbon filter. I usually mix up about 200G of water for water changes. So far no issues.

discocarp
10/04/2012, 06:35 AM
You can use just DI. It provides perfect water quality but it just doesn't last long. DI can be recharged though to save on expenses.

rogersb
10/04/2012, 10:47 AM
Have you looked into kati/ani de-ionizers?

kelp47
10/04/2012, 11:48 AM
Thanks for the feedback.
Crusty, please excuse my ignorance, but what is ATO?
Thanks for your input, discocarp.
Rogersb- no, I haven't looked at Kari/ani DIs, but I will do that now!

Crusty Old Shellback
10/04/2012, 12:42 PM
Automatic Top Off. ;) It's only ignorance if you don't know AND don't ask. :)

No wories. I have my RO unit plumbed into a manual float switch in my sump. It keeps the sump level at a constant as water evaporiates.

disc1
10/04/2012, 05:26 PM
If you don't mind the expense you can set up a glass distillation unit at your house. But it will use an insane amount of electricity to make the same amount of water and probably cost a few grand to set up.

Aside from that you're going to take a lot of trade-offs to get around the waste water issue. You're either going to have to give up on money or water quality.

What does your tap water look like?

fishyguy7
10/04/2012, 11:14 PM
get one of these if you are worried about wasting water


http://www.airwaterice.com/product/PAM1000/Permeate-Pump-With-Clips.html

Mxx
10/08/2012, 03:28 AM
I'm glad you asked. You're in Alabama? And you have a yard (or roof) instead of living in an apartment or condo? Then build a solar still. In your climate it can supply a steady free supply of perfectly purified water and doesn't take any energy to run. You'd still need to build it or buy it, obviously, as with anything.

The alternative as mentioned above is to use a large Kati/Ani Deionizing Unit along with some prefilters for sediment/carbon/etc, and you can recharge the resin with Hydrochloric Acid, which takes some caution, but isn't actually that hard. The Filter Guys have some good units for sale, and depending upon what your tap water hardness is they should be able to advise on how long the resin for each size unit will last depending upon your water hardness/TDS between having to recharge it. I have the figures they'd quoted me somewhere, but I'd have to look that up.

Solar still is definitely the more natural way to do it, thought I'm not sure what size it'd need to be in order to produce the amount of water you require.

disc1
10/08/2012, 03:26 PM
Solar still is definitely the more natural way to do it, thought I'm not sure what size it'd need to be in order to produce the amount of water you require.

Enormous! Solar still is great for making a few cups of water to drink in a survival situation. Producing a few gallons in a very large well built still wouldn't be a stretch. Producing enough water for a large aquarium starts to get into the gargantuan range.

You also have to remember that what a solar still does isn't really distillation. In distillation you bring a substance to it's boiling point. Along the way, the temperature will pause a little as it gets to the boiling point of any lower boiling compounds in the mixture removing them before you start collecting any distillate. A solar still doesn't do that. It relies only on the vapor pressure of the solution and a slight temperature change. That's why it doesn't produce nearly what a real still will. That's why we don't ever try to make our whiskey that way. It also won't purify out anything with a boiling point that is close to water either above or below. It will tend to concentrate lower boiling things in the distillate and higher boiling things in the pot, but some of both will be present in the distillate all the way through the process.

Whether or not that is a concern for a reef tank I do not know. But that's how it works. Either way I think the thing would have to be enormous and very well planned to be efficient enough to make enough water for a large tank.

swcc
10/08/2012, 04:12 PM
I'm building my equipment list for my new 75 gal reef setup, and I'm currently trying to choose my water filtering method. I was looking at RODI filters, but I really don't like the idea of all the waste water put out by the RO section of the filter. I've read the ideas about reusing the waste water, but I don't think this is going to work for me. Is anyone else running just a DI filter with success? Is there another filtering method that can be paired with DI, other than RO, to produce high quality water?

Earth...it is covered in 2/3rd. water... what is the big deal..
and if you set up your RO/Di to your washing machine...you can clean your clothes with the "waste".
The falseness is that somehow the world has a water problem... the reality... big business/government does not want to spend more(reduce profit) to provide easily accessible clean water.

Mxx
10/08/2012, 04:29 PM
http://www.solaqua.com/solstilbas.html
A gallon per day per square meter sounds like a reasonable expectation it would seem, so it wouldn't need to be too large to cover the water required for your average medium size tank.

What other liquids are we talking about in tap water or tank water which would evaporate and be collected along with the condensed water? I have no idea, but am curious. Alcohol is one liquid I can think of which might behave similarly, but is of course not in either water source.

Otherwise collecting rainwater should also be an option in Alabama, though I don't know how you would want to filter that still if so, other than through carbon.

C4rN4gE
10/09/2012, 07:58 AM
Water is cheap. Dont be worried about the waste water. If you look at your water bill, admin fees are typically the largest percentage. Unless you have acreage and water all of that with city water. Then you would have a larger portion dedicated to water.

disc1
10/10/2012, 12:03 PM
Earth...it is covered in 2/3rd. water... what is the big deal..


The problem is that very precious little of that is fresh water.

disc1
10/10/2012, 12:19 PM
http://www.solaqua.com/solstilbas.html
A gallon per day per square meter sounds like a reasonable expectation it would seem, so it wouldn't need to be too large to cover the water required for your average medium size tank.

From the article..
As water evaporates from the solar still basin, salts and other contaminants are left behind. Over time, these salts can build to the point of saturation if the still is not properly maintained and flushed on a regular basis. Properly operating a still requires about three times as much make-up water as the distillate produced each day. If the still produced 3 gallons of water, 9 gallons of make-up water should be added, of which 6 gallons leaves the still as excess. The excess water flushes the still basin through the overflow to prevent salt buildup. If this is done on a daily basis, the flushed water is of approximately the same quality as the original feedwater that was added to the still. The excess water is of suitable quality that it can be used to water landscaping, wash pots and pans, etc. No sediment or sludge will buildup if the still is properly operated and flushed daily.

So you're still looking at a 2:1 waste water ratio. Although I guess you don't have to fill it from the tap you could use any water source.

Let's think about a gallon per square meter. Let's say we need 4 gallons per day, that's a decent sized tank between top-off and weekly water changes. So we need 4 square meters of solar still, if we achieve the output of the one mentioned. To put that into terms Americans understand, that is about 6'6" by 6'6". And then what do you do one day when you need more water? Say a coral slimes out and you need to do a few rapid water changes.

What other liquids are we talking about in tap water or tank water which would evaporate and be collected along with the condensed water? I have no idea, but am curious. Alcohol is one liquid I can think of which might behave similarly, but is of course not in either water source.

I don't know, it would depend on the source of the water. I only mention it because there seems to be this idea (especially around RC) that any time you evaporate and condense water that makes it distilled. People try to call the condensate off their airconditioner or dehumidifier the same thing as distilled. That just isn't the case. I only mention it to illustrate the point that if there were something there you're not going to get it out.

Otherwise collecting rainwater should also be an option in Alabama, though I don't know how you would want to filter that still if so, other than through carbon.

Rainwater can have a lot of nasties in it. First of all, every raindrop has at its core a speck of dust. But moreover, rain picks up a ton of dissolved gasses from the air. The CO2 isn't so big of a deal because all it does is drop the pH. But the other constituents of "acid rain" are soemtimes things you don't want in your tank. All the NOx species will become nitrate eventually. The SOx species will become sulfate, maybe not as big of a problem as nitrate but still.

And even this is assuming the rain came from a perfectly clean sky. Our air is rather polluted these days. With all the industry going on, there's a lot of stuff going up into the sky that comes back down with the rain.

The moral of that story is that rainwater isn't nearly as clean as you would like to think it is. Again, simply having evaporated and condensed does not make it distilled water.

Hzuiel
10/11/2012, 09:52 AM
I mentioned this in a thread once and got zero response at all, but there are some water distillers on the market now that are similar in price to a high in ro/di, capable of putting out several gallons a day, so if you make 2 or 3 gallons a day and store it in a larger container come time for water change you'll have plenty and it should be about as pure as possible outside of a complex laboratory. I've seen some for sale around 100, not sure if i trust that particular model but another site had several in the 200-400 range. I've seen some ro/di's up over 300.

disc1
10/11/2012, 10:23 AM
I mentioned this in a thread once and got zero response at all, but there are some water distillers on the market now that are similar in price to a high in ro/di, capable of putting out several gallons a day, so if you make 2 or 3 gallons a day and store it in a larger container come time for water change you'll have plenty and it should be about as pure as possible outside of a complex laboratory. I've seen some for sale around 100, not sure if i trust that particular model but another site had several in the 200-400 range. I've seen some ro/di's up over 300.


Got a link? That would be worth looking into. If not for fish tank purposes, I can think of several other reasons it might be cool to have a still.

Although you are probably just trading out wasted water for wasted electricity. And you can't find other uses for the energy, it's just gone.

Hzuiel
10/11/2012, 10:51 AM
http://www.amazon.com/Water-Distiller-Countertop-Enamel-Collection/dp/B00026F9F8

This one does a gallon at a time. Set a gallon before work and after work when you get home and you should have 14 gallons of water for water changes. Personally with a 10 gallon sump and 20 gallon display, I don't plan on anything but distilled water from the store for a long time.

Hzuiel
10/11/2012, 11:05 AM
Oh and the power consumption is 580 watts, running for 8 hours a day 5 days a week would cost you in the ballpark of 9-11 dollars a month in electricity and net you 10 gallons of distilled water for changes and topoff.

disc1
10/11/2012, 11:08 AM
I don't really like the stainless pot. I'd rather have glass but it shouldn't make a huge difference in quality as long as everything after it is glass.
I guess it would work if you had a really small tank and never had any emergency situation where you need water fast.

My only question that wasn't answered in the link is energy consumption. I'd want to know how much electricity cost before I tried to compare to the waste output on a rodi.

Hzuiel
10/11/2012, 11:15 AM
Scroll back up, i double posted, sorry.

Mxx
10/11/2012, 05:18 PM
From the article..


So you're still looking at a 2:1 waste water ratio. Although I guess you don't have to fill it from the tap you could use any water source.

Let's think about a gallon per square meter. Let's say we need 4 gallons per day, that's a decent sized tank between top-off and weekly water changes. So we need 4 square meters of solar still, if we achieve the output of the one mentioned. To put that into terms Americans understand, that is about 6'6" by 6'6". And then what do you do one day when you need more water? Say a coral slimes out and you need to do a few rapid water changes.



I don't know, it would depend on the source of the water. I only mention it because there seems to be this idea (especially around RC) that any time you evaporate and condense water that makes it distilled. People try to call the condensate off their airconditioner or dehumidifier the same thing as distilled. That just isn't the case. I only mention it to illustrate the point that if there were something there you're not going to get it out.



Rainwater can have a lot of nasties in it. First of all, every raindrop has at its core a speck of dust. But moreover, rain picks up a ton of dissolved gasses from the air. The CO2 isn't so big of a deal because all it does is drop the pH. But the other constituents of "acid rain" are soemtimes things you don't want in your tank. All the NOx species will become nitrate eventually. The SOx species will become sulfate, maybe not as big of a problem as nitrate but still.

And even this is assuming the rain came from a perfectly clean sky. Our air is rather polluted these days. With all the industry going on, there's a lot of stuff going up into the sky that comes back down with the rain.

The moral of that story is that rainwater isn't nearly as clean as you would like to think it is. Again, simply having evaporated and condensed does not make it distilled water.

Thanks for the detailed responses above.

That seems rather surprising in part, I wouldn't have expected the flushing of a solar still or having the input water reaching saturation to be nearly that much of a problem. I would have thought you could have eventually just scraped out any built-up salt/solids now and then...

In any case, in terms of output for a still, then say we're using a 6 sqm still, which if you're top-off requires 4 gallons a day then you'd have 50% extra each day to store, resulting in 14 gallons of extra water per week.

I certainly had the idea that evaporated and then condensed water is distilled water. I'd questioned that slightly, but never found anything to the contrary.

Have you ever happened to come across any research I could read further on about the quality of rainwater? It'd something which would interest me from an intellectual perspective at least, even if I'm going to myself stick to my RODI unit. I wouldn't have imagined CO2 and Nitrogen gas to be a problem with rainwater. It will reach equilibrium anyway if just sitting in a container.

I'd not so long ago looked into recycling water change water from a softwater freshwater tank through a KATI/ANI DI unit with rechargeable resin. There were some potential issues there, but a number of upsides as well.

disc1
10/11/2012, 05:55 PM
Not nitrogen gas. NOx means NO, NO2 etc. These are not nitrite and nitrate, even though they have the same chemical formula they don't have the negative charge. They are neutral molecules and they come from everything from car exhaust to pine trees. When you dissolve then in water they react to eventually form nitric acid which from your tanks perspective is nitrate.

There was a paper someone posted on the latest rainwater thread in the reef discussion board. If I get back to my computer later I'll try to find it.

FWIW I have seen it rain straight mud here in Arkansas when the winds get up in west Texas. The dust gets up there to the point that the raindrops leave brown spots.

disc1
10/11/2012, 06:00 PM
Oops. I can't edit from my phone but that second sentence has an error. NO and NO2 are oxides of nitrogen alright but they don't share formulas with nitrite and nitrate. I originally had something else and didn't pay attention to how I changed it. NO2 has the same empirical formula as NO2- but NO is definitely not nitrate.

Either way, both species will quickly find their way to being nitric acid. It is a real problem. It erodes statues and rots the paint on old cars. That's what you've always heard called acid rain.

MONSTERUP
11/02/2012, 09:54 PM
what about upgrading witha second membrain to cut the waste in half

kelp47
11/03/2012, 10:20 PM
Thanks for all of the great suggestions. I have to do some research on some of the things mentioned above before making a final decision... (I got sidetracked lately as I've been gathering quotes--I have to get a tank with a custom overflow because of placement in the house.)

jrpark22000
11/05/2012, 07:58 AM
sorry, reply in wrong topic.