Ro Water Problems

[bushman3]

My water is all borehole or well water that is incredibly hard I still installed an RO unit with all the bells and wistles, its been running for about 6 weeks and I have just recieved an ro tester. On testing the water I am getting 47ppm, this seems pretty high. I have been using the water for weeks without seeing any major problems but being the perfectionist that I am I would like to improve on this, any ideas from anyone on how to do this or what to add on to improve the quality???

or should I justuse it as it is??

 

[AZDesertRat]

What is your raw water TDS? What RO membrane do you have and is it a 98% rejection rate or something less like 90% rejection rate. What is your flow rate from the unit? Is it close to its rated flow? If it abovethat it could be the RO membrane is not seated properly in the housing and water is short circuiting around it and not being fully treated. What is the water temperature and pressure?

 

[Paintbug]

what are your well water levels testing at? do you have a DI chamber, or is it just a RO unit? 47 is pretty high, but if your well water is really high that could be why.

 

[bushman3]

Well water is very high 1100 ppm, I do not have a DI chamber as far as I know. I have 3 4 bar of pressure and produce about 150 litres of water a day at about 19 to 20 deg c

 

[bushman3]

Ro Water problems

Ro Water problems

Well water is very high 1100 ppm, I do not have a DI chamber as far as I know. I have 3 4 bar of pressure and produce about 150 litres of water a day at about 19 to 20 deg c

 

[shoddyk]

I am getting around 900ppm out of my city water. With my RO/DI it still comes out to around 50ppm.

 

[bushman3]

does that mean it is okay then to use that water constatly

 

[shoddyk]

I use it daily and have not run into any problems. I would say yes it's ok.

 

[bushman3]

how long have you been using it and have you ever had bproblems with algie

 

[shoddyk]

I am going on 6 months and I never really had any problems with algae at all. I never even had algae during the cycle phase. I started to get hair algea about 1 month ago when I took my chaeto out of my refugium but it died back to nothing as soon as I put it back in.

 

[kevin2000]

Sounds like your well water is super hard and your RO is providing a reasonable rejection rate in a bad situation. With water that "hard" it may make sense to purchase a water softener for the whole house and use the RO (probably with a DI attachment) after the pre treatment program ... just my 02 (and not my wallet ) Maybe some of our well water member may have an inexpensive method for reducing the "hardness" of the initial water source?

 

[AZDesertRat]

47 is pretty high for a new membrane. Mine is over 2 years old, my raw water TDS is 630 and my RO only TDS is 12, after DI its 0. Do you know what membrane the unit you bought has in it. Some membranes are actually 90% rejection rate nanofilters that are misrepresented as true RO membranes which are actually 98% rejection rate. It makes a huge difference as you can see. Look for a unit with a Dow Filmtec 75 GPD membrane for best results.

 

[kevin2000]

<a href=showthread.php?s=&postid=7503438#post7503438 target=_blank>Originally posted</a> by AZDesertRat
47 is pretty high for a new membrane.

Your output is dependent on your initial water source and the lousier your water source the lousier the output. Further .. membranes can wear out pretty quick with super crappy water. I don't think that a rejection rate of 96% is unusual considering the input source.

 

[AZDesertRat]

You didn't read his original post, his membrane is only 6 weeks old. 96% is not good if its a quality membrane and only 6 weeks old.

 

[jdieck]

<a href=showthread.php?s=&postid=7503605#post7503605 target=_blank>Originally posted</a> by AZDesertRat
You didn't read his original post, his membrane is only 6 weeks old. 96% is not good if its a quality membrane and only 6 weeks old.

Usually untested membranes rating can be +/- 15% depending on temperature / pressure and inlet hardness. I would not consider 96% rejection a bad membrane specially considering also the accuracy of the TDS meters we normally use.

I see three potential options.
a) A water softener as mentioned above. Which will benefit all the house considering the cost of eventually replacing water heaters, faucets, washers and such due to heavy incrustations it might worth it.
b) Adding a DI cartridge with the added on expense of replacing it too often. This might worth it if the RO consumption is relatively small
c) Sink some additional money in a booster pump and add a second membrane.

By the way, I think backflushing the membrane after each use is a must under this conditions.

 

[kevin2000]

<a href=showthread.php?s=&postid=7503605#post7503605 target=_blank>Originally posted</a> by AZDesertRat
You didn't read his original post, his membrane is only 6 weeks old. 96% is not good if its a quality membrane and only 6 weeks old.

Pretty clear this isn't a membrane issue ... its a water source issue. Once you get to super high (super lousy) water quality your membrane plugs up pretty quick and buying a new membrane is going to provide nominal and short term results.

Seems to me the issue is to provide a cost effective method of filtering the water before it gets to the RO ... something that would take it back into the std lousy water quality that many experience rather than the super lousy water quality he has.

 

[AZDesertRat]

I think you are both a little off base. I would not accept a membrane with less than 98% rejection when it is new. I never have and even had membranes tested for efficiencies at Watts Premier to back up their claims.
Yes a softener will help, it won't reduce the overall TDS but it will exchange things that are harder to remove for sodium that is easier for a membrane to remove. Yes he definitely needs a post RO DI filter but he needs to optimize the RO process first or it will blow through DI resin in a hurry. At an incoming TDS of 47 he will only get an average of 67 gallons per 16 oz of resin refill before it begins to rise.
I think membrane flushing is a sales gimmick and have seen no documented studies to prove otherwise. My raw water averages 630 but gets over 800 and never is under 550 and I have never flushed a membrane and get multiple years of service out of them. The key is to adjust your waste ratio to keep the membrane well flushed during use and you will not have any problems.
If he has iron which he has not indicated that is another problem but it too can be overcome.
Just because water has high TDS or is hard does not indicate lousy water, quite the contrary in lots of cases. Good tasting drinking water is usually high in minerals which is what gives it its satisfying taste.

 

[Mr.Nudibranch]

look at the big brain on AZDesertRat
:lolspin:

 

[kevin2000]

<a href=showthread.php?s=&postid=7504323#post7504323 target=_blank>Originally posted</a> by AZDesertRat
Just because water has high TDS or is hard does not indicate lousy water, quite the contrary in lots of cases. Good tasting drinking water is usually high in minerals which is what gives it its satisfying taste.

In the context of reef tanks .. a high TDS (which is the only measurement the average aquarist has) is a sign of lousy water .. tasting good or not has zip to do with it. I do not disagree that TDS by itself doesn't mean everything .. but that's all we appear to have to work with. Further your 2% difference in membrane efficiency doesn't mean alot in the context of the overall numbers provided .. especially when you consider the inaccuracy of the testing equipment we have. Lastly .. while I don't think an upgrade in RO membranes going to do much .. it may not be available in Africa.

 

[AZDesertRat]

A 2% difference in rejection rate is 20 or more at raw water TDS or 1000. 20 TDS going in to a DI filter makes a huge huge difference in the life of the DI resin. Again a rule of thumb is 16 oz of DI resin will treat about 3000 total TDS. So an incoming TDS of 47 will last about 63 gallons, but with a full 98% rejection the incoming TDS would be 22 and 16 oz of resin should last 136 gallons. Thats more than twice the life out of the resin. I don't imagine DI resin is any more available than membranes so again its worth the time and effort to optimize the system. Definitely worth it!
Dow Filmtec membranes are available worldwide and they should be the same quality there as here. It would be worth the extra few dollars to have it hand tested like Spectrapure and others provide to ensure you have the best available treatment.