Neptune Aquatics

RO/DI Upgrade

chicken

chicken

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Well its finally that time. My 5+ year old 4 x 100 GPD Membrane RO/DI Unit is goners. Somehow the membranes have survived many 10s of thousands of gallons of RO water I have made over the years for all my systems. Over the last month the pressure has dropped from 65 PSI down to 30 PSI. I tried flushing them and changing out all the pre-filters but no luck. I figured it was just a matter of time. In addition the steel bracket is completely rusted through due to the extremely high humidity in my filter shed.

So with that I decided it was time to build a completely new system. I have been wanting some additional capacity for a while as it takes a long time to fill up my 900g Water Change tank if it gets low. So I am building a new system based around 6 x 150 GPD Membranes. With the new system I hope to use less water with the system. My current one is setup so each membrane is directly feed water from the prefilters. The new one I will be feeding three of the membranes with water directly from the prefilters and then chaining the other 3 membranes off the first set of membranes. This should cut my waste water in half. Luckily I am in a newer home out here so my TDS at the Tap is only about 25 so by the time the waste water from the first membrane hits the input of the second membrane it should only be about 10 PSI less and the TDS should only be about 32. In addition the 150 GPD membranes are 97% efficient vs the 90% of the 100 GPD membranes so I should go through less DI Resin.

Due to the upgrade in the membrane quantity and size I could not get enough water through the typical 10"x2.5" prefilters and 1/4" tubing. I would have to much of a PSI drop and would not have enough contact time for the carbon and carbon block to do its job. Chloramine is an RO Membrane killer so I wanted to make sure it was completely removed so I upgraded the new system to 20" x 2.5" prefilters and 3/8" tubing. I would have gone with the 20 x 4.5" ones but there were just not cost effective to purchase and were a complete overkill. The 20"x2.5" filters are 2x the capacity of the typical 10" ones and about 2x the cost so it works out to the same cost per gallon.

My system configuration is going to be the same as my old system 5 stage one. Stage 1 is a 1 micron particle filter, stage 2 is a special granulate carbon for Chloramine removal, stage 3 is a KX Matrikx +CR1 0.5 micron Carbon Block, followed by the 6 x 150 GPD Membranes and then two stages of nuclear grade non color changing DI resin.

As I said I have used this setup for 5+ years now and can test my water at 18 meg-ohm and have done nothing besides change out prefilters and DI resin. So I figured why mess with something that has worked so well.

So I started building this beast last night. My good friend who works at a metal fab shop bent me some stainless steel for the bracket. I wanted it out of stainless so I did not have to deal with the rusting issues of the typical brackets. I asked him to make it a little thicker than the standard brackets so he drops it off the other day and he made it out of 8 gauge they had some laying around so he used that. The bracket alone as to weigh 15-20 lbs :) I did not realize how hard it would be to drill all the holes through that thick of stainless. I had to burn up 4 bits drilling the thing.

Here is a picture of the work in progress. I have all the filters attached and the RO housing attached. I was going to start plumbing it and realized the place I bought the membranes from sent me the flow restrictors for 50GPD membranes, not 150GPD membranes. The new ones went out in the mail today so hopefully have them Friday. I'll post some updated pictures as I finish the build. If anyone has any questions on RO/DI setups let me know and I'll see what I can do to help. Also I have a 1000' spool of 1/4" tubing and a 500' spool of 3/8" tubing if any BAR members need a few feet.

For a size comparison I put an empty standard 10x2.5" DI Resin Cartridge next to it.



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Sounds good, and yeah you'll save a ton of water by running membranes in series, however just make sure your pressure is nice and high to start with, (booster pump??) otherwise when you get to the other membrane it'll get a bit on the low side and you'll end up wasting quite a bit of water.
 
I think I am going to be fine. I have a water feed to my filter room shed from before the house pressure regulator. So I am at about 65 PSI feeding the first membrane today. From there its my understanding that you lose about 10 PSI through the first membrane so the second one should be getting water at about 55 PSI. I am currently using two other membranes on a second RO/DI system in my garage for top off (I know overkill) on my SPS System and that is after the pressure regulator for the house and its only at 45 PSI and seems to be doing fine.

I was looking at the option of a booster pump but there really is nothing out there that is small that can deal with a 150 GPD membrane little alone 6 of them. It looked like I would need to buy a $300+ pump and a $150+ 1/4+ HP motor to run it. I just cannot justify the cost of the pump and the electricity to do something like that. If you guys know of a small pump setup that could handle this capacity let me know. Thanks!
 
ah, didn't think about the sheer volume of water you're dealing with, yeah a booster pump probably wouldn't be very useful then :D

Almost wish I had that kind of pressure at my house, instead I'm stuck with 40PSI on a good day which is why I need the booster pump, my parents house on the other hand gets some crazy insane 85-90psi unfortunately that has damaged their pipes over the years now they have a pressure regulator, but if I ever move in there (I won't mind you) I'd tap directly into that line before the regulator as well! :D
 
I am planning on running the waste water out to some of the trees in my backyard. I have about 18 40+ year old redwoods on the property that have to be range from 60-80+ feet tall. So I figured it would be worth wile to put the waste water there.
 
chicken said:
I am planning on running the waste water out to some of the trees in my backyard. I have about 18 40+ year old redwoods on the property that have to be range from 60-80+ feet tall. So I figured it would be worth wile to put the waste water there.
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They might grow another 60 feet with RO waste water, just what they have been waiting 40 years for. :LOL:

Maybe washing the clothes or injecting back into the main water line, is that possible? I have been wondering what to do with my waste water. I only make about 10 gallons a week so 40 gallons waste. The waste water from my unit runs out to the pond, half a wine barrel with lilies and stuff.
 
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Greg, The problem for me is my RO is in a separate filter shed outside while my washer is upstairs on the other side of the house. Plus we have one of those new low water usage ones and I don't think you can just put water in them. As for injecting back into the main water line I would not want to take a risk at contamination, etc. So unfortunately (or fortunately for the trees) I think its going to be watering the yard.

Still waiting on the right restrictors. Hopefully they will be here tomorrow as I am getting low on water.
 
Ok the restrictors are here and the system is plumbed. I need to clean up the plumbing a little but its up and running. I have it in my garage right now which is after the pressure regulator for the house so I am only feeding it 45 PSI compared to 65 PSI in my filter shed. Even with the lower PSI I am still getting about 720GPD :) I am happy



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So what's your water bill look like? @ 1440 GPD of waste the water dept much be wagging their finger at you awfully fierce (then silently thanking you for your prompt payment)
 
sfsuphysics said:
So what's your water bill look like? @ 1440 GPD of waste the water dept much be wagging their finger at you awfully fierce (then silently thanking you for your prompt payment)
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Mike, My bill varies all over the place depending on what time of the year it is. Its only like $35 a month during the winter months while during the summer it peaks out at like $125 a month during July/August. For the year I am averaging $80 a month.

Just like PG&E, EBMUD charges more per gallon the more you use. Peak EBMUD rate is $3.27 per 100 cubic feet of water which is about 750 gallons. So I am looking at about 300 cubic feet of water to fill up my 900g Water Change tank or about $10 in water. That's cheap vs the ~$260 in cost for Salt to make up that 900g of water change water.
 
Yeah but I'm guessing your water department doesn't have as many "tiers" as PG&E and probably not to the point of getting to be 300%+ of the base :D That looks about right as far as cost per unit, which is why I laugh whenever I see people buying bottled water at costco just for every day drinking, I mean come on 750 gallons for a few bucks! Ok maybe more than a few bucks because you also get charged a sewage charge that's based upon your usage of water, but still!

I do like what you did though, I've been meaning to do a smaller version of that (2-75gpd membranes), however even with the booster pump I'm only getting pressure in the low 60s which might be border line for if they'll work in series.
 
Mike, Totally agree on the bottled water thing. Most of the bay area is so lucky with the water quality we have at our tap. I was born and raised in San Ramon so I know nothing besides EBMUB and not sure how I could not live in one of their service areas. I think Coke's bottled water is bottled right over in Hayward and is just EBMUD water carbon filtered. Gotta love that.
 
Well Success!!! I got the new RO/DI mount in my filter shed tonight and hooked up. It was a really tight fit as it just barely fit between the ceiling and the gauges on my Natural Gas heater for my FOWLR system. I only have one PSI gauge right now so I put it in line between the first and second membrane. I am getting 55 PSI there right now which sounds about right as I feed it with about 65 PSI of water. I measured the flow and am able to make 815 GPD. That rocks! Such a big difference from my old system. Now I can fill up my water change tank in a little over a day where it used to take almost 3 before. I'll get some pictures tomorrow and post them of the system running and the flow.

I am running a DIY thread on RC also. I have a few more details there as people have asked me questions if you are intersted.

http://www.reefcentral.com/forums/showthread.php?p=17384936
 
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