# Acceptable RO water at LFS?



## Jafooli (9 Feb 2015)

Hi

I purchase 25 litres RO about every 3-5 months for a shrimp tank.

The first time I purchased RO the TDS was 14. The second time I went to the shop and come home the TDS was 40! I just accepted the extra 40 TDS.

Anyway the same pattern seemed to happen another two times, however yesterday it measured at 120 TDS.
I'm pretty sure my TDS meter is fine, before going to the shop I used the last of the RO and it read 40TDS which it was when purchased about 5 months ago.

I feel like i've wasted my money, and was just wondering what everyones experiences here are? Do you test the TDS of the RO at the shop in front of them? or is the shop I've chosen unreliable lol.

Would just like some opinions as I can't see how 120 TDS is acceptable, the time I remineralise the RO it will be nearly the same as my tap TDS and I have no idea what there 120TDS consists of.

The only other option is maybe algae or something started to grow in the container where it was nearly empty for so long. I didn't rinse it out, I never do and never had problems before. I also store the container in the shed wrapped in lots of black bin bags to keep light away.

Cheers.


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## tam (9 Feb 2015)

RO water should be <10 more than that and the filter might need swapping. 120 seems very high - are they re mineralizing it? Give the shop a call and query it.

As long as you only use the container for RO, it doesn't leach anything and it has a lid on then it shouldn't go up.


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## Andy Thurston (9 Feb 2015)

Wow 120 my taps only 70. 
As above <10
Ask if they test it before sale. take your meter with you too


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## GlassWalker (9 Feb 2015)

Do be sure your RO containers are not used for anything else to rule out contamination. If my tanks are anything to go by, any growth in there will probably lower TDS, not increase it. I can see my TDS fall between each water change, presumably as ferts are used up faster than other waste is produced.

One of my LFS is notorious for not maintaining their system. I've seen up to 110 from then, but the water was "free" when I bought containers. Running my own system I get typically <5 from an input of over 300 before I put it through DI resin. That last step is probably overkill for freshwater use but is needed in marines.

Given the volume needed is so low, I wonder if it would be worth buying a really cheap system so at least you have control over it. At a low rate of production it should last a very long time after the up-front cost.


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## Jay1 (9 Feb 2015)

Soory to hijack trying to save bandwidth LOL!
So if water is safe to drink at 300 If my RO machine was doing lets say 150 how much chlorine and chloramine would still be there? 
I'm using an old Ro machine purely to get rid of high Nitrates from the tap for Goldfish but I just want Nitrates,Chloramine and Chlorine out!


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## GlassWalker (9 Feb 2015)

The pre-filters are supposed to remove the chlorine and chloramine before it gets to the RO membrane. Supposed to be really bad for the life of the membrane if it gets that far, so regular changing of pre-filters is usually recommended. Unfortunately for whatever reason, RO isn't as efficient at removing nitrates as other things. For membranes where they bother specifying it, nitrate removal might be as low as 60% compared to the typical 95%+ of most other things. If you really need low nitrates more than other things, a nitrate selective resin might be a better choice. Those resins can also be regenerated relatively easily so more cost effective than general purpose deionisation resin. I'll let others argue if you really need to lower nitrates at all...


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## Jay1 (9 Feb 2015)

Thanks GW its just I live in a hardwater area PH 8.2 and 20ppm from the taps GH KH I'll have to report back, but tonight I ran the RO which had been running constanly before I got my hands on it.
Tested the RO water just PH and Nitrate. The PH was 6 Nitrate didn't register(API kit), compared to my tank sample of 40-50PPM of Nitrate (due a water change)
Next question is I was thinking of adding JBL Adour salts?
As mixing tap water would mean I would be spending monies on tap conditioner with salts?
Was told memebrane is less than a year old 
Both pre filter and carbon have 6 months life remaining. 
TDS in front of me TAP 355 RO 150 not sure as he told me it was 14 but saw his Di resin cyclinder sitting on the worktop. So guessing just prefilter and carbon was only doing 150 odd?


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## Jafooli (9 Feb 2015)

Thanks for the replies,

The container is only used for RO and was purchased brand new. I know the container is fine as when I purchase TDS at 14, it remains at 14 for months and 40 TDS remains at 40 TDS vice versa. It is definitely the shop unless my meter is broken, but I'm 99% sure its the shop. 

I will just phone around other local fish shops and ask the questions mentioned above as I don't rate the one I use at the moment that highly.
I have no idea what people do who own Marine tanks and get there RO there lol. I presume go back for a refund. 

I will now try to track down a shop with <10 TDS. 

Jay1 its fine, thread is yours. 

Thanks again for help.


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## GlassWalker (9 Feb 2015)

Jay1 are you saying you're reading 150 after the RO filter? That's not good if so.


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## Jay1 (9 Feb 2015)

Not sure the chap tested the water in front of me using a siemens TDS prob and it read about 150?
I'll test it tommorow and come back, but TBF if the nitrates are zero coming out and I have some solids in the RO water it should be okay to use for awhile.
It was cheap 1/3 of the price of a new one and as long as my Nitrates are low I'm happy to stick into the goldfish tank I can always bring the KH GH back up with salts.
My goldfish poo like crazy always have zero Ammonia and Nitrite within 24 period of after feeding, but Nitrates are too high for my liking.
Don't get me wrong I plan on having marine at some point and will change out the membrane or get it blasted out when that time comes.
TBF its a temp fix until the new matrix colonises for Nitrate reduction.


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## Sacha (10 Feb 2015)

The guy tested the TDS of the water and it was 150? Then he sold that to you as RO?


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## ajm83 (10 Feb 2015)

Jafooli said:


> Would just like some opinions as I can't see how 120 TDS is acceptable, the time I remineralise the RO it will be nearly the same as my tap TDS and I have no idea what there 120TDS consists of.



Give them a ring and let them know, it sounds like their membrane is donald ducked. Quite how they are happy to sell this without checking it is beyond me.


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## dw1305 (10 Feb 2015)

Hi all,





Jay1 said:


> Not sure the chap tested the water in front of me using a siemens TDS prob and it read about 150?





ajm83 said:


> Give them a ring and let them know, it sounds like their membrane is donald ducked. Quite how they are happy to sell this without checking it is beyond me.


 I'm with "ajm83", that isn't really acceptable. 

cheers Darrel


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## Jay1 (10 Feb 2015)

Sorry guys the TDS kit he used was in a different scale . To make it clear I bought a cheap RO MAN 50G unit cheap.
Just came back from the LFS and he tested it at 24 TDS.
Spoken to the LFS chap and suggests that the carbon and pre-filter will need doing, but as I'm keeping goldfish 24 TDS is good enough though.
*On another note whats the TMC buffer salts called, usually retails around £14 odd pounds for 200grams? *
He said its more stable than the JBL stuff? 
The buffer should stablise the PH to 7.4 as I'm @ 6 with the RO water.


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## dw1305 (10 Feb 2015)

Hi all,





Jay1 said:


> Sorry guys the TDS kit he used was in a different scale . To make it clear I bought a cheap RO MAN 50G unit cheap.
> Just came back from the LFS and he tested it at 24 TDS.


 Even that is still high. All TDS measurements are really in microS (electrical conductivity) so that is in the range of  40 - 48 microS (dependent upon the conversion factor used, but usually 1 microS = 0.64 ppm TDS).





Jay1 said:


> On another note whats the TMC buffer salts called, usually retails around £14 odd pounds for 200grams?He said its more stable than the JBL stuff?


 I'm not even going to go there. All I can say is that it is all b*ll*cks. If any-one starts going on about "_special salt mix/formula" etc_ they are either deluded, or being _"economical with the truth"_.

You can make up your own buffering salts (to raise either dGH or dKH, or both) for pennies.

If you have really hard tap water?  (if you aren't sure you find out from your water supplier), you can cut the RO with tap water. You don't need much volume of tap water, so even if it is high in agricultural nutrients it doesn't matter.

If you don't want to use tap water, or don't have a hard supply, you can use the mixes here <"James' Planted Tank - Re-mineralising agent for RO">.

cheers Darrel


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## Jay1 (10 Feb 2015)

Agreed its not 4-6 TDS at the local fish shop LOL! 
The more I read the more marketing wheel comes up. 
I think your statement is about right as I can imagine alot of people come on here newbies like me asking the same old questions time over time!
I only started this RO to reduce the Nitrates on my tap water to save water changes as I don't like clincal chemcial tanks.
The LFS said he cuts it 50/50 neat, but only uses only 8% across his tanks which means he doesn't even bother to de-cholrinate.
Seems like more I try to solve basic issues I'm sepnding more money and time to balance it. 
Darrel appreciate the replies and I know it pains you in answering LOL.
Thanks for the link its* exactly* what I was after!
Jay


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## ian_m (10 Feb 2015)

Jay1 said:


> Seems like more I try to solve basic issues


What basic issues are you trying to solve ? Nitrates in tap water are good for planted tank.


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## GlassWalker (10 Feb 2015)

Jay1 said:


> *On another note whats the TMC buffer salts called, usually retails around £14 odd pounds for 200grams?*


I'm guessing you're thinking of Tropic Marin Re-mineral Tropic. You can get it in bigger sizes to get the unit cost down, but certainly DIY could be an order magnitude cheaper still.


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## Jay1 (11 Feb 2015)

ian_m said:


> What basic issues are you trying to solve ? Nitrates in tap water are good for planted tank.


Yep good for plants bad for fish LOL!


GlassWalker said:


> I'm guessing you're thinking of Tropic Marin Re-mineral Tropic. You can get it in bigger sizes to get the unit cost down, but certainly DIY could be an order magnitude cheaper still.


Thanks GW decided to mix my own But thats the one for 200g it mixes about 800litres of water? The self mix stuff about 2000ltres odd litres depends upon how much buffering I guess.


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