RO/DI question

[dmbedard]

How do you get the resin in the third stage of the RO/DI system to fill up completely?

I put it in and it seems full, I tamp it a little and then run the water through. Inevitably it ends up 1/2 full within a week.

Does this affect my water adversely?

Thanks, Diane

 

[poknsnok]

do you have a TDS meter... if you do the test the water. if all is working right you should be around 0ppm to 3ppm for the water to be good

 

[reefrubble]

Diane has one of the spectra pure meters. They go down to .25 to .50 PPM. They show Red when you need to changh the DI resin. Ted

 

[fahz]

Diane something doesn't sound right what kind of cartridge are you filling? A well packed cartrridge should should stay full packed.

Fahz

 

[poknsnok]

TDS

TDS

<a href=showthread.php?s=&postid=6959217#post6959217 target=_blank>Originally posted</a> by reefrubble
Diane has one of the spectra pure meters. They go down to .25 to .50 PPM. They show Red when you need to changh the DI resin. Ted

Thats a nice one... does it have a built in TDS? Im curious what the finished products TDS is... Mine is an e-bay special that will run from 0-3ppm as tested with a calibrated TDS meter.

 

[Aquatic Hamster]

I put the amount of resin in my chamber as listed by the maker. It only fills it over a little over half in my case. Thinking "well this isn't enough" I added more to where it was a little over 3/4 full in the chamber. I see TDS in the 3ppm to 6ppm range. I suspect I would have received the same results as if it were only half full. A TDS meter will double check if there is problems, in case you don't trust the built in lights. If the TDS is near 0, than half full is fine. I'll check the TDS level about every 2 weeks.

Its kind of disgusting to know my tap water is around 390ppm.

 

[fahz]

Hate to say this but you guys and girls are missing something and it could be creating problems for you. With a TDS of 390 you should be able to get to zero no problem. What type of RO/DI system do you have? Are you running a horizontal or vertical DI housing?

Fahz

<a href=showthread.php?s=&postid=6961862#post6961862 target=_blank>Originally posted</a> by Aquatic Hamster
I put the amount of resin in my chamber as listed by the maker. It only fills it over a little over half in my case. Thinking "well this isn't enough" I added more to where it was a little over 3/4 full in the chamber. I see TDS in the 3ppm to 6ppm range. I suspect I would have received the same results as if it were only half full. A TDS meter will double check if there is problems, in case you don't trust the built in lights. If the TDS is near 0, than half full is fine. I'll check the TDS level about every 2 weeks.

Its kind of disgusting to know my tap water is around 390ppm.

 

[poknsnok]

mine is horizontal on top of my ro units.. I get 3 because the last stage is carbon and a few carbon "bits" cause the small solids reading. test the water before the carbon and it should be zippo

 

[Aquatic Hamster]

Ahh the debate that a tank will flurish with 0ppm TDS but will completely die off at 3ppm TDS. Problems with a rating of 3ppm TDS, give me a break. Everybody should know that I immediately received a PM from this guy trying to sell me stuff.

 

[poknsnok]

3ppm is fine.. up to 8 is ok... 0 is better, mine tested at 3 just a few minutes ago... but it is time to change the di resin for me..

thats pretty funny the guy is stalking this thread

 

[fahz]

Chad:

Sorry for trying to help and I didn't try to sell you anything and I'm not stalking your thread, I guess I thought the principal behind RC was helping others. The only thing I offered was some advise on DI resin. I figured you have everything you need to make your system work except the expertise. RO water need full contact with DI resin so running it half full is doing little for you. Horizontal cartridges should be run fully packed. I offered you advise from someone who deals with DI resin everyday, sorry for trying.

Fahz

 

[robthorn]

bouncing the di cartridge off the ground or a counter or whatever will help pack the resin in tightly fill and bounce until it doesn't pack anymore. ro membranes work more on percentages than how many tds's it will pull out. good ones range anywhere from 97 minimum up over 99% . check your tds before and after the membrane and do the math. if your not getting at least 97% it may be time for a new or better membrane. the better your ro membrane the longer your di resin will last. di resin also comes in different capacities and some will clean better than others. purolite nrw37 seems to be the best for our application as far as capacity and price and also how low of manufacturing solvents released into your ro/di water. I saw someone using carbon after the di which is what I do and I believe is a good idea. I use a .5 micron block and my tds after the whole process flashes between 0 and 1 on a calibrated tds 1 hanna meter. john at FAOIS sells the purolite resin mentioned above.
remember that 100 gpd membranes are not of the same quality of say a 75 or 25 gpd membrane and really should be avoided for what we are doing.

 

[ichthyman]

Ahh the debate that a tank will flurish with 0ppm TDS but will completely die off at 3ppm TDS. Problems with a rating of 3ppm TDS, give me a break.

Actually, it depends on what that 3ppm is. Check this article for clarification. Even in small quantities, chemicals that are missed by the RO membrane or leaked by saturated DI resin can be a problem in our aquariums.

Diane,

Those 10" cartridges will hold approximately 1 1/2 pounds of resin. There should be no gaps in a properly filled unit. Some cartridges come with a foam insert which will assist in keeping the media tightly packed. IIRC, there is a decrease in efficency when a mixed bed resin is allowed to seperate into it's anion and cation parts as the synergistic effect is lost. Loose fills will allow the anion and cation to seperate since they are of different weights.

 

[poknsnok]

so your saying these less expensive systems sold on EBAY for around 100.00 listed for reef use are not good ideas?? Ive used aquasafe systems and get good rejection.

 

[robthorn]

in my opinion it either works or it don't. some of them have perfectly good cartridges and membranes and will work fine most of the time. if you want better I am sure that is also out there. some of the purolite resin actually pulls the tds lower than some other brands. it is measured electrically down to 18.3 mega ohms instead of 18.2 . how much of a difference is this? I have no clue.

 

[ichthyman]

so your saying these less expensive systems sold on EBAY for around 100.00 listed for reef use are not good ideas?

Not all ROââ"šÂ¬Ã¢"žÂ¢s give the same rejection of salts. With the links below you can compare the performance of DOWââ"šÂ¬Ã¢"žÂ¢s 26, 36, 50, 75, and 100 gallon per day membranes.

http://www.dow.com/PublishedLiterat...seps/pdfs/noreg/609-09010.pdf&fromPage=GetDoc

http://www.dow.com/PublishedLiterat...seps/pdfs/noreg/609-00382.pdf&fromPage=GetDoc

The 100gpd membranes do not reject as much salts, bad stuff, as do the 26/36/50/75gpd units. At standard home operating pressures it is a 90% to 98% comparison. Of all the membranes, a 100gpd will exhaust its post DI resin in fewer gallons and, IMO, not cost effective for our application. For ease of comparison I chose to highlight DOWââ"šÂ¬Ã¢"žÂ¢s Filmtec membranes but most name brands perform at similar ratios.