What is YOUR TDS ?

W

wxman

I have a 6-stage, RO/DI system hooked up and am presently reading about a 9 TDS. IS THIS GOOD? Or is it time to change the 'yearly' filters? Just curious. My tap water, for the heck of it, reads about 185 TDS.

Interesting point...even though I'm getting a 9 TDS, by the time I gather it in a 'perfectly clean' bucket, it reads about 15. I wonder why? I did notice that someone else had a thread out there a while back that was something similar to this.

BUT, is 9 a good reading for a Coral Reef Tank.......OR SHOULD I TRY FOR PERFECTION AND GO FOR 0?

Thanks for any advise.
 
If your RO is working optimally you should read 0 Total dissolved solids.


If it's not, then your DI may need changing, or your Membrane could be leeching solids thru.
 
If you are getting that with a DI filter then something is wrong, most likely it is time to change the DI. If no DI then that probably is about right. My TDS used to be around 450 out of the tap and I was getting around 10 without DI. After I installed a DI I'm at 0.

Depending on how much water you produce, yearly might be a little long for the filters. I usually change mine every 6 months or so. The RO membrane should last a couple of years.
 
Tap 189, DI 0, although lately it's been showing 1 as the best TDS result after DI. I am just too lazy to order a DI membrane..

stan
 
@Flamenco-t wrote:
Tap 189 said:
Just for clarification, it is DI media or a DI cartridge. The only membrane in a RO system is the one within the white horizontal housing affixed to the metal / plastic bracket.

I see so many people talk about changing membranes, when they often mean filters. Hoping to help reduce that occurance. :)
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@janakaybravo wrote:
When I get a 1 TDS I order some filters. Kay said:
Remember that your prefilters, i.e., the sediment filter(s) and carbon filter(s) before the membrane have little if any effect on tds. Its primarily the RO membrane that reduces tds, and the DI removes whatever is left after the RO.

Russ
Click to expand...
 
200's out of the tap. RO takes mine down to about 9 tds and then 0 after DI.

IF you don't have a flush kit for your RO membrane I would get one so you can flush the membrane once in a while. Then check the water before the DI and see what reading you get. And check that against your reading after the DI. That should tell you how well your DI cartridge is working and if that needs to be replaced.
 
Do you check this right after you turn the valve on ?

When you initially turn it on, there will be some disolved solids, you need to let it run about 5 minutes or so to flush the whole system in order to get the actual reading.
 
@Flamenco-t wrote:
Do you check this right after you turn the valve on ? When you initially turn it on said:
That burst of not-so-clean water you get out of any RO system is called "TDS creep" and is one of the reasons you don't want to have your RO or RODI feed a float valve in your sump, for instance. Everytime the sump level drops just a little, it will kick on the RO for just a short time. If the system is repeatedly cycling on and off, a relatively high percentage of the water you get out of the system will be TDS creep water.

Russ
Click to expand...
 
After seeing this thread and realizing that my 8-9 ppm was not normal, I began to investigate my unit. I was getting the same ppm before my DI canister! I had noticed before that the water going into my DI unit trickled down the inside and then up through the center of the unit where the media is. So I took the canister off, filled the space with water that was already filtered thus eliminating the air gap around the media center and put it back together. Tadaaah :D Now my TDS reads 0-1 ppm (after running a few minutes). And I have checked it several times since eliminating the air space.

I can't figure out the mechanics of why it would make a flipping difference and the only reason why I filled the canister in the first place was because watching the water trickle down the empty space was bugging me.
 
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