Tap water TDS 550, how many RODI stages should I use?

[Schraufabagel]

I currently have a 4 stage filter for my tap water that is 550 TDS. I run through DI resin in about every 2 months for my 25 gallon tank. My tap water is not treated with chloramines. My filter does manage to remove everything so my output is 0 TDS. Lastly, I use the RODI buddy booster pump since I live in an apartment.

I'm wondering if there would be any benefit to adding a 5th or 6th stage?

 

[JoshH]

I currently have a 4 stage filter for my tap water that is 550 TDS. I run through DI resin in about every 2 months for my 25 gallon tank. My tap water is not treated with chloramines. My filter does manage to remove everything so my output is 0 TDS. Lastly, I use the RODI buddy booster pump since I live in an apartment.

I'm wondering if there would be any benefit to adding a 5th or 6th stage?

How much TDS is coming out of your RO Membrane?

 

[rtparty]

Depends what that 550 actually is. My house runs between 250-400 TDS and I run a 7 stage BRS unit. I have a 50g and 120g tank but don't do water changes all that often. I go through at least 10-15 gallons of top off a week. I rarely have to replace any DI resin. Like I have replaced the anion resin once and the mixed once in the couple years I have ran the Pro setup from BRS.

 

[Schraufabagel]

Depends what that 550 actually is. My house runs between 250-400 TDS and I run a 7 stage BRS unit. I have a 50g and 120g tank but don't do water changes all that often. I go through at least 10-15 gallons of top off a week. I rarely have to replace any DI resin. Like I have replaced the anion resin once and the mixed once in the couple years I have ran the Pro setup from BRS.

I make around 5 gallons each week. Probably around 25 - 30 gallons a month (with the extra being for my ATO and for my freshwater tank top off). I have a 25 gallon reef tank, so my ATO is only 5 gallons.

Used a AquaCheck 7 test strip on my tap water. Here are the results

Hardness: 500
Total chlorine: 0 - 0.5 ppm
Free chlorine: 0 ppm
pH: 7.2 - 7.8
Total alkalinity: 240 ppm
Cyanuric Acid: 30 - 50 ppm

 

[Schraufabagel]

How much TDS is coming out of your RO Membrane?

I can run it and check

 

[Schraufabagel]

How much TDS is coming out of your RO Membrane?

About 50 TDS is coming out of my RO membrane. Also, just noticed that my final output water is still 10 TDS, so whatever comes out of this thread, I'll do that before replacing the DI resin again

 

[Schraufabagel]

How much TDS is coming out of your RO Membrane?

For background, my filter is setup in the following way
Sediment -> carbon block -> RO membrane -> DI resin

I checked the TDS after the sediment and carbon block and it was ~520. I replaced both of those about 3 weeks ago

 

[JoshH]

About 50 TDS is coming out of my RO membrane. Also, just noticed that my final output water is still 10 TDS, so whatever comes out of this thread, I'll do that before replacing the DI resin again

50 is rather high, no wonder your DI resin is burning up so quickly, how much pressure is going into your system?

Sediment and Carbon do very little to reduce TDS and are there to protect the membrane above all else

 

[Schraufabagel]

50 is rather high, no wonder your DI resin is burning up so quickly, how much pressure is going into your system?

Sediment and Carbon do very little to reduce TDS and are there to protect the membrane above all else

My pressure gauge says around 50 PSI. Everything is connected through my RODI buddy booster

Should I disconnect the booster and try running it without it?

 

[JoshH]

My pressure gauge says around 50 PSI. Everything is connected through my RODI buddy booster

Should I disconnect the booster and try running it without it?

No no, just trying to guage the functionality of your membrane itself before suggesting anything

 

[Schraufabagel]

No no, just trying to guage the functionality of your membrane itself before suggesting anything

Is it possible that I have the waste water and filtered water lines coming out of the membrane switched on accident? And that the waste water is actually the 50 TDS it's seeing

 

[JoshH]

Is it possible that I have the waste water and filtered water lines coming out of the membrane switched on accident? And that the waste water is actually the 50 TDS it's seeing

If it was truly your waste water your reading would be higher than 520 TDS. How old is the membrane?

 

[Schraufabagel]

If it was truly your waste water your reading would be higher than 520 TDS. How old is the membrane?

The TDS coming out of the membrane line is 50 TDS. That's the one I thought might accidentally be the waste water feeding into the DI resin.

The membrane is around 8 months old

 

[JoshH]

The TDS coming out of the membrane line is 50 TDS. That's the one I thought might accidentally be the waste water feeding into the DI resin.

The membrane is around 8 months old

What membrane do you have now?

 

[Schraufabagel]

What membrane do you have now?

100 GPD Reverse Osmosis Membrane - DOW Filmtec

The DuPont (formerly Dow Chemical) Filmtec 100 GPD membrane features a 98% rejection rate at 50 PSI which makes it the most commonly used 100 GPD membrane used in the aquarium industry. If you require slightly faster water production and have good water pressure this is one of the better...

www.bulkreefsupply.com

 

[Schraufabagel]

I figured out the pressure issue. I had the RODI buddy plumbed to the pressure gauge in the wrong spot. I consulted the guide and reconnected it in the right spot. The pressure is in fact 90 PSI. So the booster pump is working

 

[rtparty]

You should have less than 5 TDS out of your membrane. Either the membrane is bad or not seated properly. Trying taking it out, making sure the housing is clean, and re-seat it.

 

[Schraufabagel]

You should have less than 5 TDS out of your membrane. Either the membrane is bad or not seated properly. Trying taking it out, making sure the housing is clean, and re-seat it.

I’ll take a look tomorrow and try reseating it