TDS rare in RO/DI..

[Gen21]

Im not sure if this thread would be in this forum.. if not please change to the correct one please...

The question is.. what can do or cause a high TDS level in my reef?¿

This is because... A couple weeks ago I changed all the cartdriges of my RO/DI SpectraPure system... it is 4 stages and this time I added one sediment prefilter before booster pump in order to keep it away from dust, sediment and that kind of solid material... I always used SpectraPure 60gpd TFC membranes but this time I had to changed brand for Captive Purity 100gpd, I changed flow restrictor and everything...

In my local area, the tap water is really DIRTY!! but I'vent had any problem with this water before (using SpectraPure membranes)... I measured some values today getting:

PO4 - 0.1
NO3 - 0
kH - 21°
TDS - 764
Temp - 15°C

The water before the membrane (after 2x sediment carts and carbon block filter) is 560TDS.. but after the membrane the values are:

PO4 - 0
NO3 - 0
kH - 1°
TDS - 040

And after Spectra Pure Solid DI the lel of TDS si 035

So... In case I measure Si and this be 0ppm... Can this water be used for my reef?¿

I bought a new TDS Hanna meter, I changed twice the carbon block filter 0.5 microns... I put my own membrane housing with my membrane in a friend's RO/DI system and the water out from the membrane drops to 002 TDS (the tap water on my friend area is 300TDS)

Could be the problem with the high TDS on the water in?¿ or maybe a chemical that this membrane cant eliminate?¿ What else do I need to measure?¿

Comments will be appreciated!! Thanks!!!


...

 

[Gen21]

No one can help?¿ =(

 

[ocndyver]

have you tried adding an additional DI, my ro unit has 2 DI chambers

 

[Gen21]

Hey Erik.. thanks for your post...

My unit has only one DI and I've not tried to add a second one.. but since I got this unit I'vent had any problem with only one DI.. I could try to add a second one but Im almost sure both DI's would be exhausted in a couple weeks for the high TDS coming from the membrane.

The question still.. Why does the membrane cant reduce TDS?¿

 

[TheH]

It looks like the DI filter is taking in 40tds water and producing 35tds water? I think this is the problem. The RO filter is reducing 560tds to 35tds (94% rejection) so that sounds fine.

 

[Gen21]

Yeah TheH...

The membrane is reducing from 560 to 40tds and DI reduce to 35tds... I made some maths and I got around 96% rejection so this mean that the membrane is working fine.. Do you think I would change again DI?¿ add another one?¿ maybe add the silica buster and then Max Cap Spectra DI's?¿

Thanks!

 

[TheH]

I would just try to replace the DI filter you have. Seems it is defective or used up.

 

[Gen21]

Thanks again TheH for your comments...

I had to bought a new DI but Kent Marine brand... and the TDS after DI is now 025... but not drop until 000tds... I supposed that the TDS in the membrane outlet would be (in case the membrane is working fine) no more than 003tds.. and this one at home still 040-039 in other houses out of my local area is 002... and if the DI work with 040tds I think it would be exhausted in less than a month...

What do you think?¿

 

[cabrego]

do you have the RO/DI hooked up to a pressurized reservoir tank for drinking and storage?

What is the RO pressure?

One of the problems i that your dealing with really dirty water! So, your RODI needs to be working efficiently in order to handle that.

 

[Gen21]

Cabrego.. thanks for your post...

My RO/DI is for my aquarium use only... I dont have pressurized tank.. only the booster pump aquatec 8800... and the pressure is 90psi...

That's right about the dirty water... and making some maths TheH and I got 94-96% rejection (it's working fine)... but even today I changed my DI for a new one and the TDS still high (I think) in 025tds, with no PO4, no NO3, no Si, 1°kH...

Can I use this water?¿ or not?¿ What do you think about this?¿ What can you recommended to me to do?¿

Thanks!

 

[FreakSRT]

Wow, that is some really dirty water. I thought my area was bad with the city water being a 75 on the tds meter.

 

[Gen21]

Hey FreakSRT...

Dont worry about your water is really clean!!! hehe... in most areas in Mexico City the water is around 250-350TDS... so all of us needed RO/DI... but.. in my own case... the water of my area is now very very dirty!!!!!! so thats a real big problem... because now my RO cant fight with it... and I dont know what else I can do with... my sistem needs the water and now a friend is supporting me with... but I cant still dependeng on him..

Regards!

 

[nanojg]

Thats not dirty water, i would love to have tap water in the 500's! Last time I tested I had TDS of over 1200 from the tap, I think after RO/DI it was in the 20's...I use it and have not had any problems.

 

[Gen21]

Hi nanjg...

then your TDS meter shows 120x10?¿ at least here my meter not touch more than 950TDS.. but really is dirty water...

Today I measured Si with Salifert.. and I got:

membrane outlet (before DI) 2.5mg/lt
DI outolet 0.1mg/lt

Where are you from nanojg?¿

Greetings from Mexico.

 

[LifeAquatic]

You have the DI filter hooked up after the membrane right? With my RO system the water goes in at 440ppm. Comes out at 7ppm. It then passes thru one DI chamber and drops to 000ppm TDS. Hope this helps.

 

[TheH]

Do you have the DI filter hooked up in reverse? I'm not sure if this matters though.