RO Question: Good vs. Waste Water

[JeffProe]

Hi all. I hooked up my new RO unit today and am putting it through it's paces (Checking for leaks, flushing everything out). I let it run for a while and collected the good and waste water in identical containers. I found that I'm running about 2.5 times more waste water than good. Is that normal? Is there anything I can do to make that a little better in favor of good water? I'm on city water and my pressure seems to be very good. I don't have a pressure gauge to know the PSI, but it seems to be very good water pressure.

Thanks for the help!

Jeff

 

[Thumper]

Your ratio is about right and if you figure out a way not to waste water let us all know, lol

 

[JeffProe]

Thanks for the input. I got a little scared when I read somebody's post that said they were getting 5:1. It seems that that is not the norm though.

 

[captivereefs]

normal is about 4-1. I run the waste water line into my washing machine.

 

[the21kid]

I worked on my RO/DI unit this weekend and something occurred to me. I have a 6 stage unit and the waste water doesn't come out until it's been through 4 stages....sediment..precarbon...carbon and then I forget the 4th stage. My issue with my own water is nitrates...howver I collected both waste and 6 stage clean water and they both tested for zero nitrates. Is it possible that I could use both the waste and "pure" water since the waste water does collect at a much faster pace?

 

[the21kid]

Membrane is the 4th stage for me....so the only things the water is not going through that I can tell is the DI and the polishing stages...any advice

 

[steve-s]

The DI stage removes phosphates and silicates. If your tap water contained NO3, I would bet it will also have PO4 and silicates, only way to be sure is test after the RO stage. I would use the water after the DI for the tank otherwise.

Cheers
Steve

 

[ASpec]

I run the waste water line into my washing machine.

As in you have the RO drain line straight into your wash machine or you fill a seperate bucket and dump it into the wash machine?

 

[captivereefs]

right into the wash machine. I have a T-installed so when it gets full I can sebnd the waste water down the drain while the clothes wash.

 

[the21kid]

So on Sunday I started filling a 33 gallon trashcan with both "waste" and RO/DI water. I mixed salt and let it sit...since the temp out of the tap has to be cold.....got home last night and tested for PO4...came out with a .25 reading...if that. It was kind of hard to tell. Is that a good reading...obviously a 0 reading would be better but is that even possible with PO4?

 

[ellisz]

You put the waste water and the RO/DI in the same container? This will take the benefits of having RO/DI water away. You can use the waste water for clothes or maybe watering plants but you don't want it in the fish tank. Might as well use tap.

If I misunderstood what you are doing, sorry

 

[the21kid]

You are most of the way there....I tested the "waste" water for nitrates since that was my problem with tap water. It came out at 0..it was suggested earlier that before I start saving this water for tanks that I test it for PO4 as well...I did that and came back with a .25 or better reading. My quandry was that I am watching this water run down the drain but it's been through 4 stages of RO...and it's lacks the nitrates that I wanted to get rid of anyway. What's the harm in using water that has been through all but a DI and polishing stage?

 

[ASpec]

If I misunderstood what you are doing, sorry

I think you misunderstood, as I did when I read it.

I was thinking the same thing... Why have an RO/DI if your going to mix the waste water with the "pure".

He is testing to see something. He said his 4th stage was the RO membrane. He wanted to see if the DI/Polishing stages (5 and 6) are doing anything positive for the water.

 

[ASpec]

The21Kid: Whats your TDS after stage only stage 4?

 

[the21kid]

I am sure that if I use a TDS before and after the DI stage I will get a lower reading. But my tap water quality is only high in nitrates from my tests. It doesn't contain a high amount of other pollutants that may be present in other enthusiats tap water. So I figured I would save a quid or 2 but not having 75% of my input water go down ye ol' drain....just wanted to see if anyone (good to see some) other people had thoughts or maybe considered this

 

[the21kid]

Aspec...I sit here embarrased cause I don't own a TDS yet...working on getting one to run that.

 

[ellisz]

I guess if the TDS was low enough, it could be used but for most, a RO/DI unit is used to get pure water for the tank. You are filtering it and then mixing it with the waste. I guess it might be cleaner than what you started with ... never tested that myself.

With a PO4 of .25, you will have algae issues at some point. The DI filter will remove this but you add it back by adding the waste. Unfortunately, with the RO/DI, you waste water. There has been more than one thread on that matter alone.

Try it and see what happens. I used tap water for years on a FO tank with no problems. I moved and upgraded to a bigger tank and went to a reef setup and then had red slime algae like crazy. The RO/DI fixed this.

Good Luck

 

[the21kid]

TDS is on the way....when Paypal gets it sh*t straight today. Thanks for all the advice...I will keep you informed. I have an artificial set up so the total purity of my water is not as important as you reef and LR keepers. I will keep an eye out for the algae issue.