How many stages for RODI

[Timrpn]

Hi everyone! I was wondering how you determine how many stages you need when you purchase your RODI machines. Is there a formula or a rule of thumb for incoming TDS. Do you just buy a 3-4 stage and see how it goes and build off of it?

Thanks

 

[40g Nano]

I run 2 sediment filters along with a resin and can get it down to 1 tds, also depends on your water

 

[Woodyman]

Hi everyone! I was wondering how you determine how many stages you need when you purchase your RODI machines. Is there a formula or a rule of thumb for incoming TDS. Do you just buy a 3-4 stage and see how it goes and build off of it?

Thanks

Do you have any ideas of your incoming feed water quality?

Well or municipal?

High or low TDS?

Chlorine or chloramine?

These questions and more can narrow down an appropriate system for your needs.

 

[Uncle99]

I have only used 4, sediment, carbon, membrane and DI.
0 TDS.

 

[Dcloser12]

City water. 150-250tds incomming 5 after membrane, 0 after both di resin canisters.

1 1micron sediment filter.
2 1 micron carbon filters
2 ro membranes
2 di canisters.
0tds.

I have to change the filters once a year. I have a 300 gallon tank with a 100 gallon sump.

Water changes about 20% once a month

 

[Timrpn]

I currently have the AquaFX barracuda. It does up to 100GPD.

AquaFX Barracuda RO/DI System-BAR

www.aquariumwaterfilters.com

Out put at the end is about 5-7 TDS. I am not sure at the moment what my incoming is, I am at work right now.

 

[Woodyman]

I currently have the AquaFX barracuda. It does up to 100GPD.

AquaFX Barracuda RO/DI System-BAR

www.aquariumwaterfilters.com

Out put at the end is about 5-7 TDS. I am not sure at the moment what my incoming is, I am at work right now.

If your getting 5-7 TDS out at the end your DI resin is exhausted and needs replaced. Might also want to add a second DI housing.

 

[Timrpn]

If your getting 5-7 TDS out at the end your DI resin is exhausted and needs replaced. Might also want to add a second DI housing.

which seems odd to me, I have the color changing resin and I would say that 2/3 of it is not changed color yet.

 

[Dcloser12]

If your getting 5-7 TDS out at the end your DI resin is exhausted and needs replaced. Might also want to add a second DI housing.

Agreed. I get 5 from my membranes before it even touches a resin bed. 1tds is a dirty membranes or depleted resin. 5 to 7tds is alot

 

[Dcloser12]

which seems odd to me, I have the color changing resin and I would say that 2/3 of it is not changed color yet.

How is it packed? It doesn't always deplete. Mixed beds could use up all the cation or anion without depleting the other leaving the appearance that you still have usable resin left when in fact you only have anion left and your not filtering copper or some other element out any longer.

 

[Woodyman]

which seems odd to me, I have the color changing resin and I would say that 2/3 of it is not changed color yet.

Mixed bed resin which is what would be within your current cartridge contains both cation and anion beads to pull out differently charged ions.

You may have have exhausted all of the cation or anion beads in the housing so those are the ions slipping through giving you the 5-7 TDS.

There's more to it then this, just keeping it general.

 

[Timrpn]

How is it packed? It doesn't always deplete. Mixed beds could use up all the cation or anion without depleting the other leaving the appearance that you still have usable resin left when in fact you only have anion left and your not filtering copper or some other element out any longer.

• A mixed bed 1:1 mixture of anion and cation gel type ion exchange resins

I use

Kolar Labs Lewatit - Di Resin Colour Indicating - Nuclear Grade - 1​

 

[Woodyman]

• A mixed bed 1:1 mixture of anion and cation gel type ion exchange resins

I use

Kolar Labs Lewatit - Di Resin Colour Indicating - Nuclear Grade - 1​

I would suggest getting 2 additional housings and run 3 stages of DI.
1 cation cartridge, 1 anion cartridge, and 1 mixed bed. In that order.

Or if you don't want to do that 2 mixed beds, but it sounds like you are exhausting one a lot sooner so separate beds would be the best and most cost effective solution going forward.

 

[Dcloser12]

• A mixed bed 1:1 mixture of anion and cation gel type ion exchange resins

I use

Kolar Labs Lewatit - Di Resin Colour Indicating - Nuclear Grade - 1​

A single bed isn't terrible but they do deplete faster. I would plum in another resin canister at least. Check your tds from your membrane. You may be pushing excessive solids into the di chamber. What size are your sediment and carbon filters?

 

[Timrpn]

I would suggest getting 2 additional housings and run 3 stages of DI.
1 cation cartridge, 1 anion cartridge, and 1 mixed bed. In that order.

Or if you don't want to do that 2 mixed beds, but it sounds like you are exhausting one a lot sooner so separate beds would be the best and most cost effective solution going forward.

Thanks, I will have to research and see how I can add on to my current setup. I am sure it can't be that hard

 

[Woodyman]

Thanks, I will have to research and see how I can add on to my current setup. I am sure it can't be that hard

It's relatively simple. Knowing more about your source water could narrow down solutions as well. I would recommend getting at least a single 3 pole inline TDS meter to check your incoming, RO, and RO/DI.

It sounds like you have one inline TDS already that checks the final output. So a three way would provide a way to check additional filter housings if/when you add more.

 

[Big Smelly fish]

I like to have two DI cartridges.

 

[Dcloser12]

Always use the lowest micron filters pre membrane. The more solids you stop here the less of a chance you have of clogging a membrane and the better the ro output as it has less solids to filter. This means less work for the di resin also. Cheap replacements yield cheap results. Done correctly its a once a year expense and in this hobby, that's a blessing lol

 

[Woodyman]

Always use the lowest micron filters pre membrane. The more solids you stop here the less of a chance you have of clogging a membrane and the better the ro output as it has less solids to filter. This means less work for the di resin also. Cheap replacements yield cheap results. Done correctly its a once a year expense and in this hobby, that's a blessing lol

This is solid advice. You can easily over filter, but most source water isn't ideal.

Personally I run a whole house 5 micron. My RO/DI is setup with a 0.2 micron sediment followed by a 1 micron and 0.5 micron carbon blocks. Then it goes through 2 RO membranes setup in series, followed by 3 stages of DI. My membranes produce ~2 TDS water so my DI isn't changed very frequently. My incoming is typically ~200.

 

[Woodyman]

This is solid advice. You can easily over filter, but most source water isn't ideal.

Personally I run a whole house 5 micron. My RO/DI is setup with a 0.2 micron sediment followed by a 1 micron and 0.5 micron carbon blocks. Then it goes through 2 RO membranes setup in series, followed by 3 stages of DI. My membranes produce ~2 TDS water so my DI isn't changed very frequently. My incoming is typically ~200.

Over filtering won't do anything negative other than lower your water pressure, which can always be corrected with a booster pump. Most installations should have one anyway for proper efficiency although you don't need one.