RODI Troubles

[PlantsBirdsAndFish]

Hey guys I'm new to the RODI scene and have had really nothing but troubles with this four stage from Marine Depot.

After adding an auto shut off kit my tds out of the RO membrane went from 8 to 14. After adding an RO bypass in order to prevent tds creep the TDS out of the membrane went from 14 to 22. If I open the flush valve it drops from 22 down to 16 but can't get 0 out the DI stage and 16 is still way more than I would like.

What is going on here? I thought I needed to trim the flow restrictor but even completely bypassing it via opening the flush valve the TDS is still way too high.

The unit is only 2 months old and I have a 98% rejection 100 gpd dow filmtec membrane

 

[lapin]

What is your incomming TDS?
Out of your RO is 8 or 14?
Then that good water goes to your DI, yes?
Then it goes to your DI?
What is TDS out of your DI resin?

 

[Dom]

Taking readings at different points in the RODI is nice when trying to determine which filters need changing. Ultimately, what is important is the TDS reading of the finished product.

That being said, what is your TDS coming out of the RODI?

 

[PlantsBirdsAndFish]

Thanks for the quick replies. As I have mentioned currently my product water is 0 when I leave the waste line flush valve open. The water coming out of the membrane is 16 tds. When I close the flush valve to put the water through the flow restrictor, the water coming out of the membrane goes up to around 22 and the DI takes a very long time to reach 0 if it does.

Before I put the auto shutoff kit on the water coming out of the RO membrane was 4 tds in flush mode and 8 tds in production mode and didn't take long at all for the product water to reach 0

The water out of the tap is 188 tds

 

[Dom]

Thanks for the quick replies. As I have mentioned currently my product water is 0 when I leave the waste line flush valve open. The water coming out of the membrane is 16 tds. When I close the flush valve to put the water through the flow restrictor, the water coming out of the membrane goes up to around 22 and the DI takes a very long time to reach 0 if it does.

Before I put the auto shutoff kit on the water coming out of the RO membrane was 4 tds in flush mode and 8 tds in production mode and didn't take long at all for the product water to reach 0

The water out of the tap is 188 tds

Ok... If I am understanding correctly, while the water used with your salt mix is reading zero, other points within the RODI system are showing TDS levels of some kind. Is this correct?

If so, it leaves me wondering if your TDS meters at different points in the system need to be calibrated?

 

[PlantsBirdsAndFish]

Ok... If I am understanding correctly, while the water used with your salt mix is reading zero, other points within the RODI system are showing TDS levels of some kind. Is this correct?

If so, it leaves me wondering if your TDS meters at different points in the system need to be calibrated?

Yes you understood that correctly. It takes significantly longer for the product water to reach 0 tds when the tds out of the RO stage is more than 14.

The two sensors on inline meter on the unit likely do not need calibrated because I tested the water both sensors are measuring with a separate handheld meter and they are the same.

 

[PlantsBirdsAndFish]

I might add that the pressure is ~63 psi and has not dropped since I first got the unit.

 

[lapin]

The water out of the tap is 188 tds. The water coming out of the membrane is 16 tds.

188tds x 5% = 9 tds If your membranes are 95% rejection rate

When I close the flush valve to put the water through the flow restrictor, the water coming out of the membrane goes up to around 22 and the DI takes a very long time to reach 0 if it does.

Sounds like waste water.

Before I put the auto shutoff kit on the water coming out of the RO membrane was 4 tds in flush mode and 8 tds in production mode and didn't take long at all for the product water to reach 0

This makes no sense. When in flush mode you should have only waste water. The flush valve relieves the pressure in the RO. This allows water to run on the outside of the membrane flushing the crud off the outside. Pressure is needed to force water thru the membrane and produce good water.

 

[PlantsBirdsAndFish]

188tds x 95%= 17tds ; about right

Sounds like waste water.

This makes no sense. When in flush mode you should have only waste water. The flush valve relieves the pressure in the RO. That pressure is needed to force water thru the membrane and produce good water

No, 17 tds after the RO stage starting with 188 tds water would be a rejection rate of about 91%.

It's 98% rejection rated membrane at 77F. With a minimum of 96% rejection it should be giving me 7.5 tds water off the membrane which I'm more than ok with.

The problem is that I'm getting 21 tds off the membrane with the flush valve closed which is a rejection rate of 88.8% which implies something is horribly wrong. The tap water I measured to be about 75F. Along with a head pressure of 63 psi it should be giving me 4-6 tds water off the membrane.

Could it be chloramines? I looked up my city's water analysis sheet for this year and there's no mention of chloramines

 

[lapin]

It's 98% rejection rated membrane at 77F. With a minimum of 96% rejection it should be giving me 7.5 tds water off the membrane which I'm more than ok with.

I corrected my post for the calculations, I was in a hurry and did it wrong.

Could it be chloramines? I looked up my city's water analysis sheet for this year and there's no mention of chloramines

I dont think it is anything in your water. I think your unit is plumbed wrong.
My internet is the pits. I cant look up any of the BRS or youtube videos that shows how a unit should be plumbed. Thats where I would start if I had your problem.

 

[JCOLE]

I have this same system. Have you contacted Marine Depot? If not then I would contact them. They have great customer service and technical support. They will get you taken care of.

 

[Jay Z]

pictures?

 

[Saltyreef]

I went with a spectrapure 90gpd maxcap standard, no flush kit and a DI bypass.
My tds @ home is 320-400 on any given day.
Before i make water, ill flush the tap im using for a minute or two, hook up the unit and make sure the di bypass is open and ill flush the RO membrane for 2-4 minutes until i see my normal RO tds @ 6-11ppm. Then close the DI bypass so water flows to the two DI cartridges.
My system has the .5 micron carbon blocks and high cap resins but i have no issues what so ever. Sometimes i think the flush kits make these systems so much more difficult to understand and use properly. Its mostly just good in theory anyways. The DI bypass valve does more for the system than a flush kit will ever do.

 

[Reef-junky]

A basic idea of how an RO/DI filter works and how to set it up

An RO filter is a membrane. The membrane is partially permeable so it removes unwanted ions and molecules. Applied pressure is used to over come osmotic pressure. How an RO works Inside an RO membrane Basic RO filter

www.reef2reef.com

 

[Reef-junky]

How a Reverse Osmosis Deionization (RO/DI) System Works

Having water quality and algae problems with your reef aquarium? It could be your tap water. Check out the Marine Depot guide to reverse osmosis filtration.

blog.marinedepot.com

How to Install an RO/DI System

Today on BRSTV we are going to show how quick and easy it is to install a RO/DI system for use with your reef aquarium. It is super easy and basically anyone who can start a saltwater tank can set one of these up as well. Disclaimer

www.bulkreefsupply.com

 

[Reef-junky]

My guess is something is hooked up wrong

 

[Mark3]

I agree....most likely plumed wrong....my tap is about 150 tds and 0 out and I just use the ro-buddy ...you should be able to get to 0 or not more than 2 tds

 

[Saltyreef]

Could it be chloramines? I looked up my city's water analysis sheet for this year and there's no mention of chloramines

If you have a decent carbon block, then no.

 

[PlantsBirdsAndFish]

Well I just decided last night to try and fill my mixing bucket and even after a week of zero use the water coming out of the membrane with the flush valve closed was 10 tds and my product water only spiked up to 3 before dropping to 0 within 2 minutes.

For the past month it would spike up to 9 tds off the product line and take nearly an hour to go down to zero. I stopped using the unit all together because I was afraid of burning up the di resin putting 21 tds water through it.

So yeah, I've done nothing differently, but somehow it just randomly started operating as it should.

 

[PlantsBirdsAndFish]

I went with a spectrapure 90gpd maxcap standard, no flush kit and a DI bypass.
My tds @ home is 320-400 on any given day.
Before i make water, ill flush the tap im using for a minute or two, hook up the unit and make sure the di bypass is open and ill flush the RO membrane for 2-4 minutes until i see my normal RO tds @ 6-11ppm. Then close the DI bypass so water flows to the two DI cartridges.
My system has the .5 micron carbon blocks and high cap resins but i have no issues what so ever. Sometimes i think the flush kits make these systems so much more difficult to understand and use properly. Its mostly just good in theory anyways. The DI bypass valve does more for the system than a flush kit will ever do.

That's exactly what I have installed on mine. I open the di bypass and flush the membrane for a few minutes before closing the valve and closing the bypass and it worked really well at first but sometimes it just doesn't work correctly.

That's actually a really great idea though. From now on I'm going to flush the tap for a few minutes before anything gets into the unit.