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gopens
10/25/2006, 10:53 PM
well after droping tons of money at my LFS, i decided to get a ro unit. what is a good tds range. mine is at 8. is that to high or to low.

bertoni
10/25/2006, 10:55 PM
What is the TDS of your tapwater? After a breakin period, I'd hope the TDS of the output water is less than 1/10 of the tapwater. This unit doesn't have DI, correct?

AZDesertRat
10/25/2006, 10:57 PM
In order to know if it is good or bad you need 2 or 3 numbers. First what is the tap water TDS ? You should be seeing a 98% reduction with the RO if it is working correctly. So if your tap water TDS is about 400 you are right on. If you have a RO/DI your DI TDS shoul be 0.

gopens
10/25/2006, 10:57 PM
correct no di. the original tap water is 140.

AZDesertRat
10/25/2006, 10:59 PM
How much water have you run through the new RO ? You need to let about 5 gallons go through it to get it "broke in". If your tap is 140 then you are still pretty high.
I hope you bought an RO with a 75 GPD RO membrane and not a 100 GPD nano filter as the 75 is 98% efficient and the 100 could only be 90% efficient.

gopens
10/25/2006, 11:02 PM
well i have only ran about .5 of a gallon so far. i was told to leave it running all night, and it should be ready.

AZDesertRat
10/25/2006, 11:05 PM
Shouldn't have to run all night but I suppose it wouldn't hurt anything. What brand of unit is it?

gopens
10/25/2006, 11:13 PM
well i have only ran about .5 of a gallon so far. i was told to leave it running all night, and it should be ready.

Buckeye Hydro
10/26/2006, 05:23 AM
Agreed - no reason to let it run overnight. My goodness. You're getting about a 94 % rejection - hopefully that rejection rate will come up a little. Check your numbers and post again...

gopens
10/26/2006, 07:48 AM
i am sorry, but maybe i honestly don't understand. what does the percentage thing matter. i mean isn't there a good number were your tds should be. to be perfectly honest, if a good tds number is 5, and my normal tap water is 50. i purchase a ro unit and it takes my water down to the good 5. isn't that all that matters. but thats only 10 percent (i think, i am tired). see i am shooting for a good tds number. to be honest, i don't really care if its not working to its fullest potential. as long a i got good numbers that all that matters to me. oh and this morning my tds was at 7 ppm. again can i use this water for my tank? thanks guys and gals for all the imput...

kau_cinta_ku
10/26/2006, 08:07 AM
any chance on buying an add on di container for your setup? that will bring you to 0. the % thing means how well your unit is working. most ppl like to keep their TDS below 3 (5 at the most) but those are ppl using an rodi system but 7 isn't bad and will be fine for your tank. but having a 75 GPD RO membrane should bring your TDS down to 2 or 3 also the % means your wasteing more water

AZDesertRat
10/26/2006, 08:09 AM
The "good" number you are trying to achieve is 0. TDS is not a measure of any particular contaminant so anything other than 0 could contain things you do not want in your tanks. Things which RO is not particularly good at are nitrates, silicates and phosphates, all of which can be bad for a reef system. DI helps to eliminate these and get to your goal of 0 TDS.
If you paid money for a RO system that is supposed to perform at a certain level why would you not be concerned if it is not working to the level it was supposed to ? That does not make any sense. If you buy a new car and it only runs on 3 of the 4 cylinders and gets half the advertised gas mileage would you also let that go? Depending on the membrane used you should be seeing 98% rejection in most cases with RO so you TDS should be no more than about 3 with RO only. 3 is not acceptible to me so I have a dual DI system following my RO so it is a true 0 TDS.

gopens
10/26/2006, 08:13 AM
thanks sam. whats so great is i am on a well. so no water bill. yes i can add a di canister. how much do they run and are they easy to install. thanks and i will be using my ro water if 7 ppm is fine.

kau_cinta_ku
10/26/2006, 08:21 AM
http://www.purelyh2o.com/product.php?productid=16194&cat=260&page=1

they run around 40.00 and is well worth it to acheive 0 TDS and very easy to install just run your line into the canister and run another line out. easy as pie. and also will save you alot of headaches with alage and other things. but i have to agree with AZDesertRat
"The "good" number you are trying to achieve is 0. TDS is not a measure of any particular contaminant so anything other than 0 could contain things you do not want in your tanks. Things which RO is not particularly good at are nitrates, silicates and phosphates, all of which can be bad for a reef system. DI helps to eliminate these and get to your goal of 0 TDS.
If you paid money for a RO system that is supposed to perform at a certain level why would you not be concerned if it is not working to the level it was supposed to ? That does not make any sense. If you buy a new car and it only runs on 3 of the 4 cylinders and gets half the advertised gas mileage would you also let that go? Depending on the membrane used you should be seeing 98% rejection in most cases with RO so you TDS should be no more than about 3 with RO only. 3 is not acceptible to me so I have a dual DI system following my RO so it is a true 0 TDS."

gopens
10/26/2006, 08:29 AM
first of all, i didn't pay nothing for it. it was a gift from my uncle. he has a plumbing company. some rich dude had him install this unit. well after about 2 hours, his wife did not like how much space it took up under the sink, so he called my uncle up and told him to come pick it up. so again it was givin to me by my uncle. and besides, it says no where on the box or instructions of an exact number it will run at. it is made by a company called Hydrotech. it is a home unit, but my uncle split it off so i have a spicket on top and a house to fill up buckets below. thanks

AZDesertRat
10/26/2006, 08:35 AM
Let it run for a while and check it again. It should get down close to the 98% rejection mark with time. Adding a DI is a smart thing to do to get to the 0 TDS level. One thing to remember, a RO membranes have what is termed "TDS Creep" which means TDS will be higher for a short time each time it first starts up. To help counter this try to use it for longer runs each time you use it. It really a matter of dilution, the longer you run it with good output the more you dilute the first higher TDS water.
Good score on the unit by the way!

gopens
10/26/2006, 09:05 AM
thanks. i thought it was a great score as well. i will be ordering that di canister mentioned above. hopefully i can get the tds nmber to zero. thanks for all the help...

suju82
10/26/2006, 10:10 AM
I got a brand new optima vision 75gpd ro/di from purlyh20 just about a month ago and had no break in period. my tap is also at 140 tds and comes out 0 tds. i make about 20 gallons a week from which i use 10 gallons for water change in my 72 gallon tank and the rest i use for drinking and it works great.

AZDesertRat
10/26/2006, 10:59 AM
Any and all RO membranes require a break in period. Some vendors do not mention it but I recommend removing any DI cartridges and running RO only water through the system until the TDS comes down to reasonable levels. This is much the same thing some vendors say with drinking water systems when they tell you to discard the first tank of water.This just extends the life of the DI resin, why send a bunch of high TDS water through it when you don't need to.