Replace DI Cartridge?

BigBlueTang

Active member
Hey all, just about to start making RO water for the initial fill for my tank. My DI cartridge is almost depleted from a couple of failed QT's and I am wondering if I should replace it or not, since I will be making almost 90 gallons for the initial fill. I think it would be a waste to waste that much DI just for the initial fill. What would you guys do? Obviously changing the DI would be better, but thinking in the money standpoint here.. Don't want to waste DI I I don't have to.
 
Don't start cutting corners.

Use the best water possible, or your asking for future issues.
 
How old are your prefilters, what is the pressure of the water, and how much waste water are you creating? Also what is the tap, pre-, and post- di tds?
A lot of people burn through spendy di because their prefilters aren't up to snuff. If you're showing any tds coming out you need to replace the di, but tweaking the filtration of the water coming into it can make the next one last much much longer.
 
How old are your prefilters, what is the pressure of the water, and how much waste water are you creating? Also what is the tap, pre-, and post- di tds?
A lot of people burn through spendy di because their prefilters aren't up to snuff. If you're showing any tds coming out you need to replace the di, but tweaking the filtration of the water coming into it can make the next one last much much longer.


Pre filters are 2 months old, Tap is ~60 ppm pre DI ~3-4 post is ~0-1
The DI isn't depleted fully yet, as it's the color changing from BRS. I just don't see the need of changing it when I'm still getting 1, and I will be making a ton of water which will really bite into a new DI.
 
To save money many recharge the DI resin. I don't, but you might want to research it. Otherwise, the most economical method would be to get a refillable cartridge and bulk DI resin, Significantly less expensive than buying filled cartridges.

Also invest in dual in line TDS meters to monitor TDS. DO NOT use water that is not 0. A reading of 1 is not acceptable because you do not know what it is that is remaining.

You might consider dual DI cartridges. When the 1st reads 1 TDS you move the 2nd into the 1st spot, change the resin i 1 and reinstall in position 2.
 
Dual DI cartridges is the way to go if you can swing it!

This is definitely not the time to cheap out. If you're in doubt and don't have a TDS meter, replace it. Consider yourself lucky; when initially filling me 260g tank a couple years ago, it was all RO/DI, and I have ~1500ppm in, and back then 37ppm out of the membrane into the DI.
 
Pre filters are 2 months old, Tap is ~60 ppm pre DI ~3-4 post is ~0-1
The DI isn't depleted fully yet, as it's the color changing from BRS. I just don't see the need of changing it when I'm still getting 1, and I will be making a ton of water which will really bite into a new DI.

You should be getting more than a couple months out of it.
Do you not have a pressure gauge, or know the waste ratio of the water? That's how you know if the conditions are right for the membrane, if they aren't you'll blow through di.
 
You should be getting more than a couple months out of it.

Do you not have a pressure gauge, or know the waste ratio of the water? That's how you know if the conditions are right for the membrane, if they aren't you'll blow through di.


I really do need a pressure gauge. That's on my wish list for Christmas.
Thanks for all of your help everyone! I think I'll just burden the cost of more DI resin..
 
I actually use three DI carts, two are refillable, and the final one is a spectrapure silica buster. The RO water is around 12TDS. The first DI cart is used DI resin, that outputs around 1-3TDS, the second erases anything left and the third cleans clean water. When the TDS of the first DI cart is the same as the RO, I pull it out, and move the second DI cart in its place, and refill the first, and place it in the second. You get crazy life out of the resins this way.
 
+1, I use two canisters and get at least 50% more use out of the resin. Purchasing a second DI canister will pay for itself quickly in reduced resin usage. It does seem like your resin is being depleted quicker than it should, but you do not want to use water with a TDS over zero, it's a bad way to start a tank.
 
+1, I use two canisters and get at least 50% more use out of the resin. Purchasing a second DI canister will pay for itself quickly in reduced resin usage. It does seem like your resin is being depleted quicker than it should, but you do not want to use water with a TDS over zero, it's a bad way to start a tank.

Yeah.. I should've realized. Stingy part of me coming out I guess. I actually have a dual DI setup, but I only have one DI cartridge in, since I got a super good deal on it from aquatic life. I think it was 35$ for the dual canister, but no DI cartridges included. I need to get on that :bounce3:

Thanks for everyone's help!! I guess I still have a ton to learn :lolspin:
 
My question is how old is the membrane, the pre-filter(s) remove sediment & or impurities (charcoal), the DI resin removes ions electrically....cations(+) & anions (-) so I have found that when the membrane starts to fail, the DI resin depletes much more rapidly, in fact, for me, that is when I know to replace the membrane.

recharging DI resin is inexpensive & quite interesting, as well as a bit messy.
Muriatic acid & sodium hydroxide (pure lye) is all that is required, if you are interested, you can pm me & I'll forward you the details or you can google it of course, it is best to have at least 4 or more DI cartridges to start with because there will be a small amount lost each recharging.
 
Even those with decades of experience can learn. One of the joys of this hobby.,

Very true. I have been a member here since 2002 and still come on everyday to see what I can learn, or maybe help out a newbie - we all were once. I know I was and made plenty of mistakes.

Rule #1. Ask questions before doing. Feel comfortable with the pro's and con's and make your decision. You will find that there are a range of opinions on many subjects - like the ideal alk for SPS, But, on some things there is not question and 0 tds is one of them.
 
Very true. I have been a member here since 2002 and still come on everyday to see what I can learn, or maybe help out a newbie - we all were once. I know I was and made plenty of mistakes.



Rule #1. Ask questions before doing. Feel comfortable with the pro's and con's and make your decision. You will find that there are a range of opinions on many subjects - like the ideal alk for SPS, But, on some things there is not question and 0 tds is one of them.


Thanks :)
This hobby is so rewarding, even though it's expensive :)
 
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