RODI @ 7ppm

[MajorJoey]

Hi
I wished to ask a question
I have been running RODI for years but never really gave too much energy in trying to reduce ppm to zero, not even sure if this is achievable , anyway
got the listed filters below on a 5 stage RODI system (which I am thinking of replacing) depending on the answers I get here
I noted here in SW Delco PA, the water authority uses the
Chloramines so I added one of the filters to the 1st chamber, I used to have just fuzzy filter in there which would turn brownish after say 6months

before I could only ever get the ppm to indicate say 16ppm output
when active with water flow and settled out for day or so
I know there is some process that will make the TDS meter measure higher when the flow is not active , regardless the little HM inline tds meter I am now using shows from the water intlet I am at aprrox 165ppm the HM output when active is now about 7ppm
question:
should I expect to get the RODI water that I use for storage,and then water changes/ topoff
to be at zero ppm?


if so, should I get a 6 stage RODI? maybe that would do it? since I am Close now
anyone do it yourself RODI? just asking
I show enough crack to be dangerous at plumbing

thanks

Joe





I did not replace membrane this time usually only do that one once a year whereas I do these below 2x , probably should make it 3x every 122 days, might make that happen this coming year

Bulk Reef Supply
2.5" X 10" CHLORAGUARD CARBON BLOCK
208955
Bulk Reef Supply
10" - 5 MICRON MATRIKX CTO CARBON BLOCK
200056
Bulk Reef Supply
UNIVERSAL CARBON BLOCK FILTER - 1 MICRON
208657
Bulk Reef Supply
ONE CARTRIDGE REFILL (1.25 LBS.) DI RESIN (COLOR CHANGING) - BRS
200123

 

[Randy Holmes-Farley Verified Community Expert]

The output from the DI part of the RO/Di should be 0 ppm TDs, and that is generally easily attained (assuming the measurement device is functioning properly). Even with bad water it is attainable. It's just a matter of how long the DI lasts.

The membrane may last many years. Only the other filters need routine replacement.

This has more:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-05/rhf/index.htm

 

[theMeat]

Hey Joe,

You want particle / fuzzy filter first. Likely a 5 micron. Changed when dirty

Then 2 carbon blocks. Changed every 6-12 months, depending on usage.

Then membrane. Changed every 2-3 years, maybe more.

Then di resin. Changed when it changes color, or if not color changing type, when tds gets above .004

That should get you down to zero. Once you start to get up to .004 it’s time for maintenance.

You should also have proper water pressure for the size membrane you want to run.
What size membrane?

 

[MajorJoey]

I am thinking it is 100 gallon a day unit

I tested also with this
COM-100 WATERPROOF EC/TDS METER - HM DIGITAL and it say 12ppm as well as the HM inline tds display that says 7ppm

gonna get me some of this cal solution and I will report back after I make sure the meters are cal'd
https://www.bulkreefsupply.com/tds-342-calibration-solution.html

thanks again for the reply

 

[mache62]

Hey Joe. Mary here. You should easily be able to get 0 TDS coming out as I'm getting that from the same water (delco area).
Let me know and we can test some of your water or bring your meter over and we can test mine as I know I'm at 0.

 

[Randy Holmes-Farley Verified Community Expert]

I am thinking it is 100 gallon a day unit

I tested also with this
COM-100 WATERPROOF EC/TDS METER - HM DIGITAL and it say 12ppm as well as the HM inline tds display that says 7ppm

gonna get me some of this cal solution and I will report back after I make sure the meters are cal'd
https://www.bulkreefsupply.com/tds-342-calibration-solution.html

thanks again for the reply

Conductivity meters for this purpose don't really need calibration. The zero is always zero (it reads zero in air, right?).

Even if somehow it got off by a factor of 2 (so 7 read as 14 or 3.5 ppm TDS), the conclusion is the same: too much.

 

[MajorJoey]

Ja it reads zero in air
That I can confirm
Not sure what I am doing wrong then
New filter after a day or so should by what I am hearing from you guys bring me to zero and Mary confirmed she can get there with same water
I ordered the pressure gauge so I will be able to give that stat this coming week at some point

The system has run this way for long time
Just never put a solid effort into it to get zero. Hopefully I can get there soon
thanks again for the help

Joe

 

[theMeat]

Gotta be a low water pressure or wrong sized flow restrictor issue. If all your tubing is routed correct

If you don't have a pressure gauge can't really tell that part

What size membrane and what size flow restrictor?

You can check to see if product water to waste water ratio is right. Should be around 4 to 1, waste to product

 

[MajorJoey]

the flow restrictor has 008 and that ratio to my eye seems correct, thinking it was a 100 gallon day
this is the membrane I am using
Dow Chemical
100 GPD MEMBRANE - DOW FILMTEC
200133 sku
this is the system I have

think I should upGun ??
I have had it for 15 years, or so , maybe go to the extreme model ? new Typhoon offering ?
could it be I am using 75g system with 100g membrane>? total jughead if I did that
if so can I just get different flow restrictor and make it 100 gallon system?

thanks again
Joe

 

[MajorJoey]

btw bookmarked both links above GREAT intel going through them and learning thanks Randy!

 

[theMeat]

That's an 800 ml flow restrictor and properly sized for a 100 gpd membrane.
It's not the "system" that is sized. The unit doesn't care what size membrane you use. The only thing that matters is that you have the right size flow restrictor for the right size membrane, which if you do have a 100 gpd membrane, you do.
The higher the gpd the membrane, the higher the water pressure needs to be.
For a 75 gpd you could get away with 45psi, matched with a 500-550 ml. flow restrictor.
For a 100 gpd membrane you need to be upwards of 60 psi.

But I'm still scratching my head because with a fresh refill of di resin you should be getting zero tds, even if only short lived.

You should check your tubing route. Should go particulate filter, carbon, carbon, membrane, di resin. On the membrane housing the side with one hose should be coming from the final carbon block. On the other side of the membrane housing there are two hoses. The one closer to center will become product water after it passes through di resin. The one more off center is waste, and should have the flow restrictor

 

[MajorJoey]

Copy Meat will check the tubing now
and report back

 

[MajorJoey]

Meat how does the auto cutoff go in. Did what you said above

 

[MajorJoey]

Ja 800 btw read the darn thing upside down now I see the arrow
Face palm

 

[MajorJoey]

https://airwaterice.com/media/pdf_files/t/y/typhoon_basic_illustration.pdf

Showing the asov

Thanks

 

[DAPG8GT]

Also are you flushing your filters before sending the water through the membrane? I had issues when I forgot to flush a carbon block and ran it through my membranes.. Both read higher for the entire life after that one mistake.. Pressure is a big factor though

 

[MajorJoey]

Dap did you just leave it that way?
not thinking I flushed them
...just cracked them open , jammed them in
and let it rip
what is the recovery from the F up?
I got the gauge coming this week so should be able to comment on that shortly

 

[theMeat]

The carbon should be flushed, or it could help clog the membrane faster. But it won’t permanently give you higher tds, and your unit has a flush valve on the flow restrictor which i’d guess you use occasionally, and that would pretty much mitigate any carbon that got pushed through.
It is a good idea to flush them thou

 

[chipmunkofdoom2]

Do you have a DI stage? Are you measuring your final TDS after the DI stage? If so, getting to zero ppm TDS is no problem. Replacing the resin will reduce the TDS to zero.

RO/DI systems are pretty straightforward. The prefilters should at least consist of a sediment filter (the fuzzy one you originally had) and a carbon block. You need the fuzzy white sediment filter because without it, the carbon blocks will clog with sediment and could be rendered useless in very short order. The sediment filter protects the carbon blocks. Since you have chloramines, you may want to run a sediment filter and two carbon blocks designed to handle chloramines (Bulk Reef Supply's carbon blocks appear to do this well). The prefilters need to be replaced every 6 months on schedule. This is to protect your membrane, since RO membranes are pretty sensitive to chlorine and chloramine. You should be replacing your prefilters on a schedule regardless of your final TDS, unless you want to test for chlorine breakthrough often as well as monitor pressure.

The RO membrane does most of the filtering of the system and only has to be replaced every few years. Every year or so, check the TDS before and after the membrane to make sure the rejection rate is still being met (usually around 96% for Dow membranes, but the 100GPD membrane is not quite as good, so YMMV). My last RO membrane lasted about 7 years, and I mainly replaced it because it dried out, not because the quality of the water decreased.

The DI resin is the last final polish before you use the water. If the water coming out of the DI stage is reading higher than zero ppm TDS, it needs to be replaced.

TL;DR: replace the prefilters every 6 months on a schedule. Replace the DI resin whenever the final TDS is greater than 0 ppm, and replace the membrane every few years (or when the rejection rate drops).

 

[MajorJoey]

Ja have Di stage and replaced DI material with in the last 10 days still ppm @7 , checked all tubing and made sure that it is routed the way meat described above added auto shutoff via documentation from air ice water company website
membrane has been replaced within last few months , have pressure gauge on order should be here this week
learned tons sofar
how to check zero on Hm meters- air read
I read the stuff Randy linked to and I know now really only the membrane and DI are pivotal
the others just clean up the incoming water and filter (debris) that would reduce optimal operation of the membrane and shorten life
I am measuring the TDS at the incoming H20 pipe and the output after the DI, that is where I have the Hm meter setup
I have another meter that one I just pop off the connection going into the hm inline and read the cup full as it is a handheld,
TDS Meters do read Identical too
, I have a couple of tees/valves and will work on putting one in after RO and b4 DI so I can take that and the other two HM connections more easily , anywhere else I should jam a valve T in there? lmk I will make it so
I get the creep concept as well and taking reading when active flow is occurring

was thinking I jacked the filters by not washing them but after reading what Meat said I agree it would not be a permanent effect on TDS
I am Stumped
I ordered a couple of the Sediment filters so will make that change soon as I get them

thanks for knowledge transfer