RO Membrane wearing out fast

[MrAwder]

I have a hydrologic Stealth RO100. I only use about 10gpd of RO water so I got the smallest system I could find. The problem I am having is that my RO membrane is taking a shit in less than 6 months. About 8 months ago I rebuilt the whole filter - new sediment, carbon and membrane. This got me from 300ppm down to ~10. 6 months later the output water is back to about 115ppm! This time I tried just replacing the sediment and carbon with no luck. So time to drop $60 on a new membrane. I really don't want to be doing that every 6 months if I can avoid it. The only thing I can figure is that it must be iron in my water. The water is municipal but obviously terrible if it is 300ppm. I can also see very noticeable orange buildup in the sediment filter.

So I have 3 options: 1) Try the "Small Boy" pre-filter to get some more life out of the membrane. 2) Try to install a $400 Iron Reduction Filter (Waterboss). 3) Keep replacing the membrane every 6 months. The small boy would be <$200 upfront cost, the iron filter is $400 plus a day of installation.

I am leaning toward trying the small-boy as the upfront cost is small and installation is easy. If I knew I would be in my current house for more than a couple years I would definitely install the $400 iron filter, but I need at least 3 years to make the investment worth it (as opposed to just buying new membranes). Any thoughts or suggestions?

Thanks

 

[Miraculous Meds]

I run a cheap $200 dollar 200gpd ro made by spectrapure. Never had my ro come out other than 0, with years of use. I change the ro membrane yearly now cause of fear of bacteria growing. But the key I think is to change the sediment filter regularly. If u change it when it gets rusty looking, u save the ro membrane and carbon filter life.

 

[Fields~of~Green]

Does your unit have a flushing function ?

Do you have a pressure gauge on your unit?

 

[MrAwder]

Yes I installed a backflush. Run it about 30 mins once a month. Pressure gauge is fully in the green.

Maybe I jsut let my sediment filter get too bad before changing. I think I might just replace the membrane this time and keep a closer eye on things going forward.

 

[Miraculous Meds]

Yes I installed a backflush. Run it about 30 mins once a month. Pressure gauge is fully in the green.

Maybe I jsut let my sediment filter get too bad before changing. I think I might just replace the membrane this time and keep a closer eye on things going forward.

Ur supposed to use that flush every time u use the ro water. that way the water just sitting in the prefilter can be flushed out instead of going thru ur ro membrane, potentially mucking it up with bacteria and algae.

 

[Granger2]

Will the size of your unit allow you to use an RO membrane that has a higher rate, such as 200 gpd? If so, I would do that. And yes, it will help to change out the cheap sediment filter often.

If I needed one and could afford it, this is what I'd buy: http://www.marinedepot.com/SpectraP..._Systems-SpectraPure-SP11392-FIROROSH-vi.html Good luck. -granger

 

[MrAwder]

Ur supposed to use that flush every time u use the ro water. that way the water just sitting in the prefilter can be flushed out instead of going thru ur ro membrane, potentially mucking it up with bacteria and algae.

Now that I did *not* know. I have it hooked up via float to a 60 gallon res. So before I start taking water from the res, I should turn it to backflush? How long should I leave it flushing?

EDIT: "did NOT know"

 

[GratefulOne]

If you have hard water (calcium) it blocks up the RO passages really fast. You need to put on a water softener first to remove the calcium and replace it with salt. The RO filter can remove salt nearly forever. Water softener are easy to build. Just find a supply company on the net. Will can buy the same parts as your local company does and build it yourself. They are super simple.

 

[Miraculous Meds]

Now that I did *not* know. I have it hooked up via float to a 60 gallon res. So before I start taking water from the res, I should turn it to backflush? How long should I leave it flushing?

EDIT: "did NOT know"

Mine recommends 20 to 30 seconds before u start using ro water.

 

[BakedBandit]

Also changing out the sediment and carbon helps a lot. If the carbon block is spent chlorine and ammonia from your water can and will kill the membrane faster than normal. Flushing when you turn on everytime after it has been sitting def helps as well. Most carbon blocks are not good for as many gal as you'd think, and if you have chloramines in you water not all carbon blocks will take care of that before it hits the membrane. I use sediment, carbon block, chloramines block, then membrane personally.

 

[SnowCreature]

The replacement sediment filters come with a message on the label that says to wash them regularly and replace every 6-12 months.
Hell, I even wash the outside of the carbon filter before I replace it.
Should change the membrane once a year.

 

[johndoe123]

Thanks guys! Learn something new everyday. I have had my ro unit for 5+ years Stealth Ro 200 unit. I change the sediment and carbon filter regularly (membranes once) Didnt know about backflushing the unit.... Thought I was due for new membranes. Had the spare parts to install a backflush and I'm back down to 3ppm + Rep all the way around. MM I gotta share the wealth before you can get more rep from me

 

[Eighths-n-Aces]

If the carbon block is spent chlorine and ammonia from your water can and will kill the membrane faster than normal. .

 

[queequeg152]

as someone said above. excess carbonate will destroy a membrane in no time at all.

this should be dealt with, usually by a water softner or an ion exchange resin.

look at your water quality report, calculate your langlier saturation index, and if your water comes up as scale prone... you should get a professional recommendation for a softner.

in the future you should monitor the pressure drop across the membrane. its a useful metric.

carbonate is "barely" in solution. when you concentrate the feed water, it immediately scales out... this gets worse as you increase the back pressure with permeate pumps and shit like that.

the only other solution is to inject acid into the feed water. this will marginally improve the carbonates solubility, but not by a whole lot.

chlorine etc will not appreciably damage your membrane as quickly as you indicate. not usually at least. i suppose if you somehow had tremendous chlorine concentrations it would, but most residential water distribution systems barely crack 1mg/l if you are lucky.

 

[PetFlora]

Check with your water department

Some use chloramines

You need a special PREFILTER for that

Flush frequency depends on how much water you use

 

[MrAwder]

Okay sounds like a water test is in order. My hesitation is that, even if I find out I need a softener... I can't exactly have someone come in to install it. Not sure if it is a DIY type job or not, but that would be my only option. The main shut-off and hot water heater are right next to my room, so I would have to completely tear down to have a softener installed.

 

[queequeg152]

softners are ****y. you need a drain, power and some space.... the foot prints are small though.

they require a drain for the backwashing of precipitate, or in the case of an ion exchange resin... to discharge the brine waste. if you have a septic system, make sure you can discharge super salty water without issues.

gonna cost you at least 500 bucks, probably around a grand.

people think ro is necessary, but it just, is not.
ro is pissy and not worth the trouble...in all but the most grievously bad water quality cases.
i grew rockwool toms absolutly effortlessly in 300mg/l carbonate without any issues....peatlite and coco lite for several years, no issues. you just get scaling of pump impellers and crap like that. its alot easier to deal with than to fuck with RO.
it just takes like 40ml hcl to drop the ph every reservoir change. but a galon of hcl costs me like 7 bucks.

 

[KONY]

Whats your well/water pressure? If its under 40psi, a booster pump will reduce the amount of waste water you have, and increase the time between filter changes.

 

[theother]

A different carbon filter will help if you have Chloramine. My fuse is though you just end to change the sediment much more frequently and the carbon maybe every other run. It's odd that your making so little water and still going through them so quickly.

I go through a membrane a year unfortunately and a lot of sediment and carbon filters also. If I don't stay on the pre filters it won't last even 6 month though.

 

[Pulsar]

Some just straight up wrong info in here. Carbon will barely even touch Chloramines, and you absolutely do not need a water softener to elongate your resin or maintain a TDS of 000 on the output.
OP: noticed you said you have your unit plumbed to a float valve. Are you making small batches at a time in a res, flushing your unit and then taking it off line, or is it continually cycling via the float valve/ pressure from your tap? If it's the latter, then there's your problem.
The tds coming out of the membrane at short intervals causes tds that is extremely high. As the bobber float only calls for small amounts of water, it causes what is called TDS creep. This destroys your membrane and exhausts the DI resin up to five times faster.
My municipal tap contains like 3X the average in Chloramine content(Rant: Chloramine is highly overhyped as being detrimental to plant health, and I personally feed straight out of the tap in dirt. In my DWC system and aquariums however, I'm all RODI)
My method:And trust me: I've been put through the ringer on dialing in the most cost efficient methods to overcome my Tap's impossibly high Chloramines( Again, all this not because I believe they effect the root system negatively, but only because Chloramines rapidly exhaust DI resin, which is expensive)
I run a 4 stage Maxcap 180GPD RODI Spectrapure unit, I make 100 gallons at a time, flush, then take the unit offline with the turn of a valve. For fillup/ ATO, which feed both my aquarium sumps and topoff Res, I employ a Spectrapure UPLC-II ATO that comes with a digital air sensor that can be adjusted between 1/10" and 4" with the use of a button. It also comes with a back up high level float switch and the same three roller peristaltic pump as their Liter Meter III. The pump can also be adjusted in 10% increments as another level of failsafe, so you can adjust the fill rate.
My ATO res is like 40 feet away in my basement. The ULPC has no issue pulling the water that distance and can actually pump vertical if needed no problem, while maintaining sufficient psi.
That's the ultimate fix dude. Albeit, mildly expensive upfront. My shit sparkles out of that water line though, I rarely have to buy DI, and I run a ton of volume through my lines. Good luck.