Recommend RO/DI

[zaiqiu]

Hi,

I am currently using the 3-stage Crystal Pro that was purchased from Aquamarin many years ago. Few weeks back, I changed the resin and charcoal filter. However I noticed that the output water still reads 40ppm with TDS reader. This is still the same even I tried to reduce the flow to dripping, still achieving 40ppm.

 

And I think that’s reason why my hair algae is growing out of control. Like to seek opinion which is the recommenced filtering system to get now?

 

Is RO a must, or I can just use DI filtering?

 

Many thanks!

 

 

 

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[Evolutionz]

What is your tap water TDS? Singapore's tap water are generally very soft with pretty low TDS (below 100) therefore RO is not a must (or infact not necessary at all). I personally use a 5 Stage DI system with 1 stage carbon and 4 stage DI water and produces 0 TDS even with fast flow rate, my tap water is 60-70 TDS. 

It sounds to me you that your resin have either expired or exhausted that's why its producing high TDS water. 

[zaiqiu]

I measured my tap water TDS is 66ppm. Hmm, my DI was just purchased new and replaced on the crystal pro.

Somehow I am guessing that it could be the design of the crystal pro. I noticed that there are free space whereby water can bypass without all going through the DI canister. That may explain why I could not get 0ppm.

Would you have link to where you purchase the 5-stage DI from? I am also looking at those table top drinking water filtration sys like below. Will this work?

https://filtech.com.sg/product/xeltro-ct22-countertop-twin-water-filter/



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[equiox]

RO is a must. And u will not look back.

[zaiqiu]

I am mindful of the slow flow rate of using RO system haha. So am thinking if DI suffice. For RO, what are you using and any recommended RO system to get from local LFS?


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[soggycookies]

I am mindful of the slow flow rate of using RO system haha. So am thinking if DI suffice. For RO, what are you using and any recommended RO system to get from local LFS?


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i got a 4-stage unit from rms. produces 0 tds water and with the booster pump, at a rate of about 5L per 4-5mins


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[Mahesh]

Since you mentioned you were using ur unit for quite long time, there may be possibility of leaking through the stages without going through the resin. I am using 4 stage and able to get 0 tds .

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[Evolutionz]

2 hours ago, zaiqiu said:

I measured my tap water TDS is 66ppm. Hmm, my DI was just purchased new and replaced on the crystal pro.

Somehow I am guessing that it could be the design of the crystal pro. I noticed that there are free space whereby water can bypass without all going through the DI canister. That may explain why I could not get 0ppm.

Would you have link to where you purchase the 5-stage DI from? I am also looking at those table top drinking water filtration sys like below. Will this work?

https://filtech.com.sg/product/xeltro-ct22-countertop-twin-water-filter/



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what u said makes sense and should be the reason why you're not getting 0 tds. i have used the Crystal pro a long time ago but don't remember having issue with it. Maybe you would want to remove and reassemble your unit? 

With a tap water TDS of 60+, there is no reason why you need RO, yes RO membrane can last a long time but you have to deal with waste water and a slow flow rate and if you stay in high floor you'll definitely need a booster pump. The trade-off is not significant enough because DI alone can reduce the TDS to 0 and still last a long time. 

This is my DIY 5 stage DI unit with all the parts sourced from taobao except for the resin. 

 

[zaiqiu]

what u said makes sense and should be the reason why you're not getting 0 tds. i have used the Crystal pro a long time ago but don't remember having issue with it. Maybe you would want to remove and reassemble your unit? 
With a tap water TDS of 60+, there is no reason why you need RO, yes RO membrane can last a long time but you have to deal with waste water and a slow flow rate and if you stay in high floor you'll definitely need a booster pump. The trade-off is not significant enough because DI alone can reduce the TDS to 0 and still last a long time. 
This is my DIY 5 stage DI unit with all the parts sourced from taobao except for the resin. 
 

I have the same concern regarding the waste water and the slow rate...if DI can achieve 0 TDS, it will do right?

I suppose DI will deplete faster? Even then replacing DI resin should be kind of affordable enough when compare with the waste water discharge with the RO system?

Hmm, then why would there still be people who go for RO instead of DI? Am I missing something here?



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[Evolutionz]

2 hours ago, zaiqiu said:

 

I have the same concern regarding the waste water and the slow rate...if DI can achieve 0 TDS, it will do right?

I suppose DI will deplete faster? Even then replacing DI resin should be kind of affordable enough when compare with the waste water discharge with the RO system?

Hmm, then why would there still be people who go for RO instead of DI? Am I missing something here?



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The end result is the same, 0 TDS pure distilled water. Yes using DI alone without RO depletes the DI faster BUT with our TDS at 60+ tds it lasts much longer than you might expect. Still, a RODI unit will last longer than a DI only unit. But is the trade-off of waste water and high cost (booster pump is almost a must) worth it? i personally think it is not. Infact, i know some reefers who use a single 20" huge DI canister and pack it full with DI resin and they last a very long time before you see TDS creeping up above 0. 

My personal usage wise, the 5 stage DI unit i have can last 6 months with a weekly 10% WC of my 170L tank, a 5L DI resin pack cost about $45 and the whole pack would last me about 15 months, the Carbon block is pretty cheap and can be bought locally below $10. That is a very low cost to maintain, and remains relatively low even if i double my tank size volume and do the same 10% WC weekly.

Most people buy RODI because that is what most shops sell and that is what they are told they need, to achieve RODI water. These are of course my own opinion and both option definitely works at producing 0 TDS water which ultimately is what we are looking for. 

 

Edited July 7, 2020 by Evolutionz

[Benq89]

23 hours ago, Evolutionz said:

What is your tap water TDS? Singapore's tap water are generally very soft with pretty low TDS (below 100) therefore RO is not a must (or infact not necessary at all). I personally use a 5 Stage DI system with 1 stage carbon and 4 stage DI water and produces 0 TDS even with fast flow rate, my tap water is 60-70 TDS. 

It sounds to me you that your resin have either expired or exhausted that's why its producing high TDS water. 

Hey Evolutionz, don't mind sharing your flow rate? For me I'm using 3 stage and i had to do 1 drip per second and the water production is driving me nuts. 

[Evolutionz]

3 minutes ago, Benq89 said:

Hey Evolutionz, don't mind sharing your flow rate? For me I'm using 3 stage and i had to do 1 drip per second and the water production is driving me nuts. 

I'll take a video when i do my regular WC, i can fill up a 5L tub in 5 mins and probably can go faster while still producing 0 tds. 1 drip per second sounds really bad! Got to check if your home TDS is very high or if your resin has exhausted. 

Edited July 8, 2020 by Evolutionz

[Indeco]

Get this mius DI from taobao, can settle ur problem liao.

Put at last stage, don't have top up DI resin also. Just change it when TDS detected will do.

[Benq89]

1 hour ago, Evolutionz said:

I'll take a video when i do my regular WC, i can fill up a 5L tub in 5 mins and probably can go faster while still producing 0 tds. 1 drip per second sounds really bad! Got to check if your home TDS is very high or if your resin has exhausted. 

Thank you. Instruction for my RODI was 1 drip per second through the control valve. Therefore didn't even attempt to push past 1 drip per second. HAHA. With what you described, it seems like you just on the tap can already. very good man.

TDS around my tap abt 80 i suppose? long time didn't measure source water.  

[Alfredphua]

Using 5 stage rodi will be better


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