Rodi puzzle

Dr RBG · Jun 4, 2023

I have a BRS 6-stage RODI unit that is 6 years old. I have changed all the cartridges according to schedule. I have noticed a change in dissolved solid readings.
Stage 1 008Stage 2 000Stage 3 003
Is something that changes 000 at stage 2 to 003 at stage 3. Seems weird. Any fixes?

KStatefan · Jun 4, 2023

Where are those reading being taken? Stage one to me is the sediment filter.

X-37B · Jun 4, 2023

Have you ever replaced the membrane?
Do you flush the membrane before and after use?
I run a brs 4 stage ro/di unit with another membrane piggy backed onto the first.
Faster di water makeup with 1/2 the waste.
I only replace cartridges when my di exit reads 3 on the inline meter. Handheld unit will register 1 when the inline reaches 3.

Dr RBG · Jun 8, 2023

KStatefan · Jun 9, 2023

I think that is the best incoming water I have seen posted here. Normally when the output of the DI stages goes up it means that it needs changed but with your water I do not know how it would be exhausted when supplied with 000 tds water.

Dbichler · Jun 9, 2023

Do you have your unit connected properly . Sediment/carbon/ro membrane/di. other thing would be your membranes are clogged or not seated correctly. Another thing would be is your di actually packed properly.

Reefer Matt · Jun 9, 2023

Dr RBG said:

I think that points 2 & 3 may be switched on the tds meter. I'd double check the wires. Also, a source water reading of 8 tds seems very low (good). What is your water source?

Buckeye Hydro · Jun 10, 2023

Your Tap water is 8 ppm? No way.

Very very unlikely. Check the location of your TDS meter probes again please.

Fishy888 · Jun 10, 2023

Dbichler said:
Do you have your unit connected properly . Sediment/carbon/ro membrane/di. other thing would be your membranes are clogged or not seated correctly. Another thing would be is your di actually packed properly.

Also check to see if your DI cartridge is right side up in the canister.

Buckeye Hydro · Jun 30, 2023

That graphic above has some problems. To avoid confusion:
*Carbon blocks are radial flow, not axial.
*Membranes are not intended to remove bacteria. In fact, the membrane manufacturers specify that the membrane should be used only on microbiologically safe water.
*The DI stages should not be connected by a hex nipple. Rather, they should be connected by a loop of tubing to allow the user to mount a TDS meter probe between the DI housings.
*The graphic misuses the word "Stage." Each filter in the system is a Stage. I think they meant "probe."
*The pressure gauge in that pic is plumbed in after the third stage, not the second stage.
*The Triple probe TDS meter, TRM1, has the green face. The blue one shown is the DM1 which has two probes.
*On the system shown, you'd ideally want four TDS meter probes: 1) feedwater, 2) permeate, 3) after first DI, and 4) after second DI.

Russ