Using RO/DI waste water in freshwater aquarium?

[StirCrazy]

Originally Posted by mark

guess the one advantage of using the RO waste is it's already stripped of the chlorine or chlromine through the carbon blocks, never liked the idea of Prime.

I used prime for 20 years on my fresh tanks, even with RO water just to be sure nothing sneaked by the filters haha, guess it was more habit then anything else, but never had an issue with it.

Steve

[Drfu]

Originally Posted by mike31154

I have no experience with freshwater aquariums, but I would surmise that the benefits of using RO water are the same for both salt & freshwater systems. With RO you are starting with a "known" water quality, that is, there are no "unknown" impurities or dissolved solids in the water you are about to use.

Most likely you can use the waste water from your RO system for your freshwater tank no problem, after all, it does originate from a source that's safe for human consumption. But without a city water report that shows what's in your tap water, you really have no idea what you're adding, in what concentration and/or what you need to dose to correct the levels of whatever you consider desirable for your freshwater tank. Keep in mind that the RO waste water is a more concentrated soup of whatever comes out of your tap, with some sediment & the chlorine removed. Even with a city water report, the report is only a snapshot & water quality can vary considerably depending on the season & what the city uses as a source. You'd need a pretty comprehensive kit or home laboratory to test for all those minerals & impurities yourself.

Below are two water reports from my provider, the City of Vernon. We have multiple water sources & there are occasions when they switch supplies to various customers due to spring run off, turbidity, water quality issues etc. Reports show Kalamalka Lake source which supplies most of the water & the Duteau Creek source which they recently spent millions on to improve quality. Duteau Creek is much softer water. 99% of the time, I am on the Kal Lake source & my TDS reading out of the tap these days is fairly consistent between 165-170.

North Kalamalka Lake Intake Water Quality 2008
Water System: Greater Vernon Water
Source: Kalamalka Lake
Facility: Kal Lake Pumpstation
Sampling Point: Kal Lake Intake
Date: 7/14/2008

INORGANIC Results (mg/L unless noted)
Aluminum <0.050
Antimony <0.0030
Arsenic <0.0050
Barium 0.027
Boron 0.021
Cadmium <0.00010
Calcium 40.6
Chloride 5.38
Chromium <0.015
Copper <0.0030
Cyanide < 0.01
Fluoride 0.24
Iron <0.20
Lead <0.001
Magnesium 19.8
Manganese <0.0050
Mercury <0.00030
Molybdenum 0.005
Nitrate (as N) 0.069
Nitrite (as N) <0.010
Potassium 5.07
Selenium <0.0050
Sodium 18.4
Sulphate 51
Uranium 0.003
Zinc 0.011

PHYSICAL Results (mg/L unless noted)
Alkalinity (as CaCO3) 152
Colour <5 TCU
Conductivity 409 microS/cm
Hardness (as CaCO3) 183
pH 7.8
Total dissolved solids 238
Turbidity 1.0 NTU

Water System:Greater Vernon Water,
Source: Duteau Creek
Facility:Headgates
Sampling Point:Headgates Cl2 bldg (1-1-SR, 5E8D)
Date of Sample:7/19/2011

INORGANIC, Results (mg/L unless noted)
Aluminum (total) 0.114
Antimony (total) <0.0010
Arsenic (total) <0.0050
Barium (total) <0.050
Boron (total) <0.040
Cadmium (total) <0.00010
Calcium (total) <5.0
Chloride 0.21
Chromium (total) <0.0050
Copper (total) 0.0245
Cyanide (total) <0.01
Fluoride 0.13
Iron (total) 0.31
Lead (total) <0.0010
Magnesium (total) 1.23
Manganese (total) 0.02
Mercury (total) <0.00020
Molybdenum (total) <0.0010
Nitrate (as N) 0.02
Nitrite (as N) <0.01
Potassium (total) 0.8
Selenium (total) <0.0050
Sodium (total) 1.36
Sulphate 3.1
Uranium (total) <0.00020
Zinc (total) <0.040

PHYSICAL, Results (mg/L unless noted)
Alkalinity (Total, as CaCO3) 14.3
Colour 75
Conductivity 38 microS/cm
Hardness (total, as CaCO3) <12.9
pH 7.14
Total dissolved solids/TDS 44
Turbidity 0.9

There are plenty of other uses for RO system waste water. Some folks use it to fill their washing machine, but to me that's pretty hard water & I'd rather not have that stuff filtering through my textiles. I use it in the garden & to flush toilets. Been considering a 'grey' water system in my house to lower the water bills. I could plumb the RO waste into that. The way things are going with rate hikes around here, if I don't do something, I may even need to give up the hobby, along with my garden.

I have heard this a couple of time now qbout the wager being hard or brackish, is ro water suitable for tropicals like corys, tetras & plants? Do i need to test for anything before using the ro water?

[StirCrazy]

Originally Posted by Drfu

So if you are using ro water for your fw tanks, what supplements are you adding to make the chem correct for fw, ie trace elements, ph? If this is the case what benefits are their using ro vs conditioned tap water? It could be more work using ro vs conditioned tap water?

My tank has tetras, corys, otos, clown loaches & of course a bunch of plants. Right now all i do is use prime & tap, let it sit for day before using and add a capful of flourish excel.

so you have a mix of soft water and hard water fish but more towards the softerside.

I do the south american biotopes, so plants tetra's angels, ect.. I add nothing to the water, I use the RO, then anything that gets added comes from my florite substrate and the tannon's leaching out of the wood. I do also add jobe plant sticks and PMDD so there is some nutrent added but not directly.

with the SA type habatats, you want the water very low in TDS and slightly acidic, I know my RO water was about 7ph, and my tank water with in a few days of a water change was down to low 6 high 5's. now if your doing african type things then you want higher tds and such but you still want that TDS to be comprised of the propper desolved particles, you can buy stuff to add to RO spicificly for that pourpose.

Steve

[Drfu]

Originally Posted by neoh

So, what's the difference between the RODI waste water and tap water? You should be dosing your macro and micro ferts with planted tanks (Kno3, Po4, etc.) (See: http://www.aquaticplantcentral.com/f...ing-guide.html) anyways, regardless of method.

Whats the TDS out of the tap? What's the TDS out of the rodi waste water?

I wouldn't see it as a problem. I had high tech planted tanks for years, and I would do it if I had both. It's still filtered through your carbon and sediment filters, so it would be much better than straight tap water, as tap water still has chloramine/chlorine in it for the most part.

I would make a batch of water from the waste water, use your prime with it, then dose your KN03, KH2P04, and trace elements in it before your water change.

However; I would do a test beforehand. I've had fish in waste water before (feeder goldfish) with no problem, so it doesn't strip needed elements from water.

Best of luck!

I got a tds meter today, my ro waste water show 220, my tap shows 200 & i tested the water in my aquarium & it shows 247 ppm.

[Drfu]

So i tested my Ro waste water for Gh & kh, both ate between 7-10 drops or 100-200 ppm, is this a bit high for a standard community tank? Again my TDS of my tap water is around 200, mo Ro waste water is around 220