RODI Di expires quick.

[Miami Reef]

I have a 250 gallon tank. My RODI unit is used for top off. Plus I make water changes to the DT and QT tanks with it.

I only changed the DI about a month ago, but I’m getting 3tds again.

The DI only gets half exhausted. I think some places need more cation vs anion than others? I have the 50/50 mix from BRS.


My tap is 157tds

Edit. I pack the media very tightly.

 

[14 foot reef]

Are you on well water by chance ? The CO2 in well water is pretty hi and will chew through the DI resins so fast.

 

[redfishbluefish]

Packed tightly is correct.

Now, are you on well or city water. If well, a common problem is carbon dioxide in the water which will quickly consume DI resin. You can install a bubbler to eliminate the CO2 before running through the DI unit.

You also mention that you used for top off. I'm hoping your top off isn't directly connected to your RO/DI unit. The reason is that every time you start your RO/DI, you get breakthrough TDS that will shoot up fairly high for a couple minutes. This too will eat DI resin. I'd high suggest having an independent topoff container that does not use RO/DI directly from your unit. The other potential issue coming directly off you RO/DI is that if and when the valve fails, and it will, it will cause a flood.

The other thing you can do to extend DI resin is to run the first ten minutes of water from you RO unit to waste. I do this very simply by having a three way valve that goes to waste. After about ten minutes, I flip the valve to run through the DI resin.

 

[shwareefer]

@redfishbluefish

I love that masterflex valve. Might have to get one. I have a Y-connector with two valves right now.

 

[Miami Reef]

Packed tightly is correct.

Now, are you on well or city water. If well, a common problem is carbon dioxide in the water which will quickly consume DI resin. You can install a bubbler to eliminate the CO2 before running through the DI unit.

You also mention that you used for top off. I'm hoping your top off isn't directly connected to your RO/DI unit. The reason is that every time you start your RO/DI, you get breakthrough TDS that will shoot up fairly high for a couple minutes. This too will eat DI resin. I'd high suggest having an independent topoff container that does not use RO/DI directly from your unit. The other potential issue coming directly off you RO/DI is that if and when the valve fails, and it will, it will cause a flood.

The other thing you can do to extend DI resin is to run the first ten minutes of water from you RO unit to waste. I do this very simply by having a three way valve that goes to waste. After about ten minutes, I flip the valve to run through the DI resin.

My RODI is directly connected to my sump with a float valve. So you’re saying that the RODI is working multiple times a day which is causing the DI to get in contact with dirty city water for many times throughout the day?

 

[shwareefer]

My RODI is directly connected to my sump with a float valve. So you’re saying that the RODI is working multiple times a day which is causing the DI to get in contact with dirty city water for many times throughout the day?

He's saying you are getting killed by TDS creep. Look it up if you are unfamiliar.

 

[redfishbluefish]

My RODI is directly connected to my sump with a float valve. So you’re saying that the RODI is working multiple times a day which is causing the DI to get in contact with dirty city water for many times throughout the day?

Yes! When your unit shuts off, "dirty" water migrates through the membrane, so that on start-up you get a bolus of hight TDS water. With my unit, it shoots up to 50 or 60 TDS and then slowly comes back down as clean water comes through. For me, to get down to 2 or 3 TDS post membrane takes about 10-12 minutes. At that point I switch to direct RO water through my DI resin. With your current setup, ever time your unit starts, and how many times is that in a day, your breakthrough TDS has to be removed by you DI. That is why you are chewing up DI.

If you're handy-dandy with RO systems, you can set up an electronic valve system to run the first x number of minutes of water to waste before going through you DI resin. But as I've already said, your best bet is to remove your topoff from directly coming from you RO/DI unit because that float valve you have is going to fail....that's a given.....and if you're like me, that will happen when you're on vacation and you'll be coming home to a major flood. :oops:

 

[Miami Reef]

Yes! When your unit shuts off, "dirty" water migrates through the membrane, so that on start-up you get a bolus of hight TDS water. With my unit, it shoots up to 50 or 60 TDS and then slowly comes back down as clean water comes through. For me, to get down to 2 or 3 TDS post membrane takes about 10-12 minutes. At that point I switch to direct RO water through my DI resin. With your current setup, ever time your unit starts, and how many times is that in a day, your breakthrough TDS has to be removed by you DI. That is why you are chewing up DI.

If you're handy-dandy with RO systems, you can set up an electronic valve system to run the first x number of minutes of water to waste before going through you DI resin. But as I've already said, your best bet is to remove your topoff from directly coming from you RO/DI unit because that float valve you have is going to fail....that's a given.....and if you're like me, that will happen when you're on vacation and you'll be coming home to a major flood. :oops:

How can I learn how to do this? Is this a difficult plumbing job? My Experience is very small with plumbing and top offs, and pictures/visual guides help me a lot. What is the type of work I need called so I can research how to do it myself?

 

[Miami Reef]

Circling back to this.

I found this 5 gallon top off container. How does it work? Will I have to manually fill the container weekly? How do I transfer this water from top off container into the tank automatically like the way I have it now?

 

[Woodyman]

How can I learn how to do this? Is this a difficult plumbing job? My Experience is very small with plumbing and top offs, and pictures/visual guides help me a lot. What is the type of work I need called so I can research how to do it myself?

If you setup the RO unit yourself you can handle this plumbing modification.

Whether you do it with a 3 way valve as shown above or just some 'T' fittings with ball valves won't make a difference. The 3 ways if you have them will save you from having to add in ball valves after a traditional 'T' since it does both jobs in one piece.

Here's some schematics I made up for a previous post.

https://www.reef2reef.com/threads/eating-up-ro-membranes.843152/post-9151562

 

[Woodyman]

Circling back to this.

I found this 5 gallon top off container. How does it work? Will I have to manually fill the container weekly? How do I transfer this water from top off container into the tank automatically like the way I have it now?

If you could elevate this container you could use this to gravity feed using the float valve you already installed in the sump, you would use this as a source container instead of your RO/DI. If you ever have a failure it will only drain as much as what's left in the container, or at a maximum 5 gallons.



You could manually fill this or set it up to gravity feed from a larger container, but then if there is a failure and say you feed the 5 gallon with a 45 gallon Brute container of RODI your looking at a 50 gallon spilled compared to 5.



I would manually fill and let it Auto top off on the same manner you have setup currently, just using this container as your source instead of the RODI unit directly.