Jestersix

What's your TDS threshold?

So obviously we want our RODI to filter out water at 0 TDS. Recently my RODI started to produce water with 1 TDS. I emailed customer support as it seems premature for the cartridge filters to start failing, given that I have only used it for 6 months and only produced roughly 198 gallons of water to date. Customer support responded by saying 1 TDS is reef safe. So the question is, do you guys replace RODI cartridges soon as TDS isn't 0? Or if not, what's your threshold before you decide to change?
 
I think 1 TDS is within the range of uncertainty for those meters so I wouldnt worry too much, if you see 2-3 tds then you are due for a change, but that isnt going to kill your tank, and and this po8nt the resin color should have mostky changed
 
I think 1 TDS is within the range of uncertainty for those meters so I wouldnt worry too much, if you see 2-3 tds then you are due for a change, but that isnt going to kill your tank, and and this po8nt the resin color should have mostky changed
Right you are. The DI resin has already changed color. I checked the water before DI and its registering at 4tds. After DI, its 1. So that means the DI still has some life left? I also realize that I might have been shortening the life of my DI resin by not disconnecting when flushing out TDS creep?
 
Did ALL the resin change color? Because it is a gradual change. That said BRS on youtube did a nice investigation video about using your resin until the end, and as it turns out that's not such a good thing because what happens is your resin will latch onto all sorts of atoms/molecules, however each one has a different affinity to the resin (fancy speak for how much it is attracted) and it turns out those with a larger attraction can knock off those with a lesser attraction so you can flood your tank with one particular type of element while capturing others when your resin is "depleted" .

That said, if you have 4 TDS, and you're sure that number is accurate, after your RO membrane you should not be going through resin that fast at all, so double check that it all went through a color change, and if so get back on the phone to the water tech support guys.

TDS creep is a real thing yeah, but unless you turn it on and off in rapid fashion that usually isn't a problem. I've never flushed my membrane (I should though) and I make a lot more water than you before resin gets depleted, and I'm running 2 canisters of resin (soon to be 3!)

Edit: here's the video I was talking about
 
The main concern that you have is wasting di media changing the media out at this point, right? I would suggest adding a second di canister at the end of your system, and installing an inline tds meter between the two. Whenever the tds between the two cartridges goes up above zero (or one or five, whatever your limit is) your output tds after the second di canister should still be zero. Then just move the second cartridge into the first canister and put new resin into the second, thus minimizing waste but ensuring optimally “clean” water.


Sent from my iPhone using Tapatalk
 
Did ALL the resin change color? Because it is a gradual change. That said BRS on youtube did a nice investigation video about using your resin until the end, and as it turns out that's not such a good thing because what happens is your resin will latch onto all sorts of atoms/molecules, however each one has a different affinity to the resin (fancy speak for how much it is attracted) and it turns out those with a larger attraction can knock off those with a lesser attraction so you can flood your tank with one particular type of element while capturing others when your resin is "depleted" .

That said, if you have 4 TDS, and you're sure that number is accurate, after your RO membrane you should not be going through resin that fast at all, so double check that it all went through a color change, and if so get back on the phone to the water tech support guys.

TDS creep is a real thing yeah, but unless you turn it on and off in rapid fashion that usually isn't a problem. I've never flushed my membrane (I should though) and I make a lot more water than you before resin gets depleted, and I'm running 2 canisters of resin (soon to be 3!)

Edit: here's the video I was talking about
Looks like color is 90% changed. Thanks for the informative video!


Sent from my iPhone using Tapatalk
 
Don’t tell anyone but with my first tank I only used RO water since we already had it in the house for drinking water. It wasn’t very good and usually took it from the 400 range of the tap water down to 20 or so. It wasn’t until I upgraded my tank that I replaced the whole RO unit and added the DI.

I would never recommend this but it gives you an idea for tolerance.
 
Frustrated! Our RODI water TDS does not stay at 0 for long at all and I am very frustrated. One month ago we changed everything except membrane - sediment filter, carbon block, bulk catalytic carbon, and mixed bed DI resin. TDS = 0. Now it is already at 3 and the resin has nearly all changed in color. I lost track of how much water we have processed, but a month?!
Last month I measured membrane output and it was like 88% less than input, which seems fine.
Do you think this is chloramine? I just got a second canister to add another DI stage, as I read in another thread. Also read about chloramine in a thread, so maybe I should buy a test kit. I thought we had had an algae issue in August due to impure water and do not want to repeat that.
Any suggestions?
 
Frustrated! Our RODI water TDS does not stay at 0 for long at all and I am very frustrated. One month ago we changed everything except membrane - sediment filter, carbon block, bulk catalytic carbon, and mixed bed DI resin. TDS = 0. Now it is already at 3 and the resin has nearly all changed in color. I lost track of how much water we have processed, but a month?!
Last month I measured membrane output and it was like 88% less than input, which seems fine.
Do you think this is chloramine? I just got a second canister to add another DI stage, as I read in another thread. Also read about chloramine in a thread, so maybe I should buy a test kit. I thought we had had an algae issue in August due to impure water and do not want to repeat that.
Any suggestions?

That is unusual. I use a lot of water in my 240G system with auto water exchange, and I usually get a year.
To check:
1) Is the flow regulator set up correctly?
If it is sized for a smaller RO membrane, you get too much back pressure.
Or maybe you have blockage?
Buy a new one. They are cheap.
2) Did you bypass the catalytic carbon for a while when replaced?
It can clog up the RO. I do that sometimes.
3) Chloramines are an issue, but with 2 carbon stages, not likely.
4) Check the seals on the inner part of refillable catalytic canisters.
Those can go missing, and then water will simply bypass the carbon.
 
Don’t tell anyone but with my first tank I only used RO water since we already had it in the house for drinking water. It wasn’t very good and usually took it from the 400 range of the tap water down to 20 or so. It wasn’t until I upgraded my tank that I replaced the whole RO unit and added the DI.

I would never recommend this but it gives you an idea for tolerance.
Fascinating. Was there ever a problem with nuisance algae when you used that 20TDS water?
 
Frustrated! Our RODI water TDS does not stay at 0 for long at all and I am very frustrated. One month ago we changed everything except membrane - sediment filter, carbon block, bulk catalytic carbon, and mixed bed DI resin. TDS = 0. Now it is already at 3 and the resin has nearly all changed in color. I lost track of how much water we have processed, but a month?!
Last month I measured membrane output and it was like 88% less than input, which seems fine.
Do you think this is chloramine? I just got a second canister to add another DI stage, as I read in another thread. Also read about chloramine in a thread, so maybe I should buy a test kit. I thought we had had an algae issue in August due to impure water and do not want to repeat that.
Any suggestions?
That does seem unusual. I am complaining about 6 months of use but to go from 0 to 3 in one month is definitely an indication that something is wrong. Which RODI system do you use and how many stages? Did you pack the DI resin tight? Does the membraine need to be changed? What did customer support say? Let us know what you find out.
 
Update on my situation: I told customer support that my issue is that they estimated my DI resin to last a year based on my usage and incoming TDS. Since it has lasted only 6 months, I am extremely disappointed. Also I've noticed the appearance of brown stringy algae since using the 1 TDS water. So they sent me a courtesy refill pack of DI resin to try again. I'm thinking since I only produce water every 2 weeks, I need to disconnect the DI and flush out a couple of gallons to get rid of TDS creep before making RODI. Hopefully that would preserve the resin longer.
 
I've been using 1 TDS for awhile now and even at 3 TDS for at least the last couple of water changes and no issues. Is it dino or cyano?
 
It looks like dino without the bubbles, if that makes any sense. It can't be leaching from the rocks because my ugly phase came and went and no nuisance algae has returned until now. Also can't be overfeeding cuz I've scaled back quite a bit since my experience with the ugly phase. The only other possibility I can think of is excess nutrients from invert deaths? I lost a couple of snail during that time and have no clue how long they've been dead. Also haven't heard the pistol shrimp snap in awhile....
 
I have an AquaFX Barracuda with sediment filter, 2 chloramine blasters (I refill with one carbon block and one catalytic carbon), 100 gpd membrane, one DI. Haven't contacted customer service but they would be assume based on past experience.
I will check into points above - thanks! I HAVE messed with the flow restrictor before, I think when I flushed the membrane
 
The snails most likely caused the issue. I had 1 snail crawl of the tank about 2 months ago and I tossed it back in thinking that it might be alive. It wasn't and cyano appeared within 2 days of it being in the tank. Removed the snail and the tank came back into balance after about a week.
 
Back
Top