Is an RODI water filter really necessary?

[DrFlu]

Hello everyone,

I have been reefing with mostly LPS/Softies for the last >10 years and recently gotten some SPS within the last few months. However, i have not been following one of the most basic principles in reef keeping: NOT using RODI water. I have been using tap water with Prime this whole time.

I have to say though, I have not been experiencing any issues as others have reported? I have not been getting cyano, dinos etc. Corals seem fine? I run a Chaeto reactor 24/7 and also a HOG1x algae scrubber. I also run GAC every few months - so that may that probably solves any heavy metals accumulation?

Nitrates: 1ppm (salifert)
Phosphates: 0.03ppm (salifert)

Am i missing something here? Is a RODI unit for reef tanks really a fundamental piece of equipment? I just couldn't justify the purchase of an piece of equipment that is seemingly not required.

 

[jgirardnrg]

I'm in the US and can't buy a rodi filter for $60. The cheapest I see them is for is closer to $200. I'm going to guess that @kittenbritches may have got hers from the marine depot closeout or if not just found a phenomenal deal somewhere. I don't need another rodi but for $60 I would've bought several spares, it's worth that just for the membrane and cartidges.

You can get a very good unit for well under $200:

Aquarium/Reef RO/DI Reverse Osmosis Deionization Systems

The best configurations of RO DI systems with Color Changing DI

www.fountainheadwatersystems.com

I have the 6 stage 150gpd unit from them.

 

[Ancient Mariner]

My main concern with RO/DI is the waste water. I feel guilty wasting so much water especially when we are in drought conditions with watering restrictions. I stopped using RO/DI years ago although I still use the prefilter and carbon filter units and my SPS dominant tank is doing great. My municipal water seems safe enough.

 

[Gtinnel]

My main concern with RO/DI is the waste water. I feel guilty wasting so much water especially when we are in drought conditions with watering restrictions. I stopped using RO/DI years ago although I still use the prefilter and carbon filter units and my SPS dominant tank is doing great. My municipal water seems safe enough.

If you have sufficient pressure and clean enough supply water (which doesn't seem to be an issue for you) you can add a second membrane to the waste of the first to cut down on the amount of waste water.

 

[Buckeye Hydro]

I did a thread quite a while ago now that asked reefers about there incoming TDS and I was shocked at how many were below 10 TDS. Not to ruffle any feathers but in some areas it does seem to be a thing. Is it easy to mess up measuring TDS? My only experience in meters are the inline variety and I know they can be installed wrong

Interesting. Would love to read through that thread!

 

[JoshH]

Interesting. Would love to read through that thread!

So what's everyone's Tap TDS and how do you handle it?

Over the past little while I've been reading lots of threads on RODI selection questions and seen some responses here and there about some who have insanely high and insanely low TDS and pressure coming from there tap. And it really got me wondering how wide of a range there really is out there...

www.reef2reef.com

Read away, I unfortunately didn't make the numbers in the poll that refined because I honestly didn't expect many people to have TDS under 100.

 

[Gtinnel]

So what's everyone's Tap TDS and how do you handle it?

Over the past little while I've been reading lots of threads on RODI selection questions and seen some responses here and there about some who have insanely high and insanely low TDS and pressure coming from there tap. And it really got me wondering how wide of a range there really is out there...

www.reef2reef.com

Read away, I unfortunately didn't make the numbers in the poll that refined because I honestly didn't expect many people to have TDS under 100.

Well up until now I was happy with my 120ppm. The issue as I see it isn't the amount of dissolved solids but has more to do with what those dissolved solids are.
Even if my water was currently "clean" enough to not need to use rodi filtration you never know when something will change that will make it not "clean" enough.

 

[JoshH]

Well up until now I was happy with my 120ppm. The issue as I see it isn't the amount of dissolved solids but has more to do with what those dissolved solids are.
Even if my water was currently "clean" enough to not need to use rodi filtration you never know when something will change that will make it not "clean" enough.

You should still be happy with 120 TDS, mine currently sits at 375 since we moved and there are others that are north of 5-600.

And you are correct, even 2 TDS really should be passed through some type of filter, even if it's just sediment, carbon and DI. Without knowing exactly what that TDS is comprised of it has no business going into a reef tank as far as I am concerned and water conditioner can't cover all the bases.

 

[Gtinnel]

You should still be happy with 120 TDS, mine currently sits at 375 since we moved and there are others that are north of 5-600.

And you are correct, even 2 TDS really should be passed through some type of filter, even if it's just sediment, carbon and DI. Without knowing exactly what that TDS is comprised of it has no business going into a reef tank as far as I am concerned and water conditioner can't cover all the bases.

If the previous poll that you posted is accurate I'd also be shocked that so many people have such a low tds from their tap water.
I am happy that mine is low enough to allow multiple membranes. I just added a second membrane to my filter and I'm considering a third.

 

[WVNed]

If you have decent water and run it through an RODI what do you get.
Perfect water for your tank and "waste" water.
But what is this waste water? Basically tap water still with a slightly higher mineral content with the chlorine and whatever the sediment filter trapped removed.
You are not sending a toxic chemical back to be treated by your local waste water plant if you put it down the drain.
I would argue you are helping reduce the load on you local waste treatment plant.
If water is truly scarce where you live then collect it and use it as you would tap water. I wouldn't drink/cook with it because once the chlorine is removed it wont remain clean enough, unless you boil it.
Wash things with it, put it in your toilet tank, water plants, use your imagination. It's just slightly harder tap water

 

[Gtinnel]

If you have decent water and run it through an RODI what do you get.
Perfect water for your tank and "waste" water.
But what is this waste water? Basically tap water still with a slightly higher mineral content with the chlorine and whatever the sediment filter trapped removed.
You are not sending a toxic chemical back to be treated by your local waste water plant if you put it down the drain.
I would argue you are helping reduce the load on you local waste treatment plant.
If water is truly scarce where you live then collect it and use it as you would tap water. I wouldn't drink/cook with it because once the chlorine is removed it wont remain clean enough, unless you boil it.
Wash things with it, put it in your toilet tank, water plants, use your imagination. It's just slightly harder tap water

Many years ago I would always use mine to fill my washing machine and then use it to wash clothes.
I agree that too many people hear the term waste water and assume it's dirty, when in reality the tds of it only goes up a little bit.

 

[WVNed]

Many years ago I would always use mine to fill my washing machine and then use it to wash clothes.
I agree that too many people hear the term waste water and assume it's dirty, when in reality the tds of it only goes up a little bit.

I am not going to argue with the mentality that wasting water is bad. It is probably is necessary in some places.
But rather than not using RODI for my tank I would, like you said become more creative with what I do with the "brine"
which is what the "waste water" used to be called. It is perfectly fine for almost everything else you use water for.

 

[Gtinnel]

I am not going to argue with the mentality that wasting water is bad. It is probably is necessary in some places.
But rather than not using RODI for my tank I would, like you said become more creative with what I do with the "brine"
which is what the "waste water" used to be called. It is perfectly fine for almost everything else you use water for.

Mine was trying to save water because at the time I was broke not because of any environmental or water limitation reasons. I no longer bother with trying to use the waste water because financially I'm considerably better off. After actually calculating how much money I'm wasting in waste water it's actually a very insignificant cost.
I didn't know that it used to be referred to brine, but I wish it would go back to that being the common term.

 

[WVNed]

Here is a pump BRS sells to put water into a pressurized tank under the sink for drinking. Notice how it is labeled.

Powered only by the hydraulic energy of brine water usually lost to the drain (i.e. no electricity required), the Permeate Pump forces product water into the storage tank, reducing membrane back pressure and maximizing available feed pressure.

 

[WVNed]

Mine was trying to save water because at the time I was broke not because of any environmental or water limitation reasons. I no longer bother with trying to use the waste water because financially I'm considerably better off. After actually calculating how much money I'm wasting in waste water it's actually a very insignificant cost.
I didn't know that it used to be referred to brine, but I wish it would go back to that being the common term.

When I was in that condition I ran my tanks with corals on Walmart distilled gallon jugs and the FOWLR with tap water.
Ya, I have been there.
Mocha helping me do a water change in 2008

 

[Gtinnel]

When I was in that condition I ran my tanks with corals on Walmart distilled gallon jugs and the FOWLR with tap water.
Ya, I have been there.
Mocha helping me do a water change in 2008

I used rodi water for my "reef" tank only. I also had a predator tank that I just used tap water for.

 

[WVNed]

I used to get RODI at Jomarrs pet shop in Nitro ( gone now). Then it got so they never had enough and I got tired of hauling the 5 gallon jugs.
I finally got my own filter.

 

[Gtinnel]

I used to get RODI at Jomarrs pet shop in Nitro ( gone now). Then it got so they never had enough and I got tired of hauling the 5 gallon jugs.
I finally got my own filter.

I miss that place. I believe the guy that owned it works at a petco in Teays Valley, or if it's not him it's a guy that looks a lot like him.

ETA- now that I think about it I'm not sure if the older man who was always there was the owner or just in charge of running it. I never knew his name though.

 

[WVNed]

I miss that place. I believe the guy that owned it works at a petco in Teays Valley, or if it's not him it's a guy that looks a lot like him.

Yes, That's him. I remember when I guess it was his mom ran Jomarr's and she always had a monkey on her shoulder.
Million years ago now.

 

[Gtinnel]

Yes, That's him. I remember when I guess it was his mom ran Jomarr's and she always had a monkey on her shoulder.
Million years ago now.

The only people I ever remember seeing was him and a younger guy. I only started in the hobby somewhere around 2000, and unfortunately I wasn't there as much as I would've liked to be, because of that previously mentioned being broke thing.

 

[WVNed]

The only people I ever remember seeing was him and a younger guy. I only started in the hobby somewhere around 2000, and unfortunately I wasn't there as much as I would've liked to be, because of that previously mentioned being broke thing.

I have kept fish here since about 1984. There used to be several booming pet shops and I raised cichlids and traded with them to get rid of the small ones. Jomarrs at Nitro, Docs at Belle, Maynard's in Charleston, 2 others whose names I cant remember. The one in Saint Albans had parrots.