RO/DI Question

[dbdisok]

It’s been a while since I changed the resin in my DI filter. So I installed the new DI cartridge and let a few gallons run through it. Well my TDS coming out of my RO unit is 001 ppm and 002 ppm from the DI filter.

Do I need to run more water through the DI filter? I don’t recall have to rinse my last DI cartridge.

 

[smartwater101]

I usually let mine run run for 30-45 min before I actually use the water. I think most people consider anything ~4 or less to be fine. I personally wouldn't be concerned with 2. Let it run a bit longer and see where you end up.

 

[dbdisok]

Thanks for your input. I’ll let it run longer in the AM. It’s strange that the TDS goes up after passing though the DI.

 

[smartwater101]

What is the margin of error for that brand of meter? My guess is it's just not a accurate reading.

 

[Shaummy]

Did you pack the DI media real tight in the cartridge? Sometimes water will actually channel/bypass the media instead of flowing through it.

 

[dbdisok]

The DI I’m using comes prepack in a cartridge.

I just spoke with a rep at Marine Depot and was advised that the DI material may have dried out and that all is need is 24 hours for it to rehydrate.

I’ll have to wait and see if that is the case. This morning I started the process and watch fas the TDS coming from the DI filter rose from 006 ppm to 036 ppm that after 5 minutes slowly began to fall back to 006 ppm.

 

[dbdisok]

What is the margin of error for that brand of meter? My guess is it's just not a accurate reading.

Both my hand held TDS meter and the in-line TDS meter are within 001 ppm. So the reading is good.

 

[AZMSGT]

It took my last new DI material to get to zero about 45min-1hr.

 

[Thaxxx]

Thanks for your input. I’ll let it run longer in the AM. It’s strange that the TDS goes up after passing though the DI.

I know when my DI gives out and I don't have a replacement on hand. I always bypass the DI until I get another. With the DI in place my water is 4ppm, with just the RO it's 1ppm.
I have no idea why. With a new DI I get 0ppm. Im thinking the DI may not be worth much to me.

 

[dbdisok]

I called Marine Depot and they are sending out a replacement.

 

[Thaxxx]

It's not defective.
DI's aren't good very long. Maybe 200 gallons. If you do lots of water changes, it can get very exspensive. Reef tanks did great with just R.O. water years ago. And a few ppm more of tds isent going to make or break a reef tank in my opinion. Just another unnecessary new tech item to sell $$.