Does anyone have a DI meter built into their RO/DI?

[SanguinesDream]

As my tap water quality is poor and the RO/DI still measures high in phosphates and DS, I was wondering if purchasing a unit with a meter built right into it would be useful or would it, as always, need to be recalibrated regularly thereby eliminating the convenience. Anyone with experience?

[Cal_stir]

you can add a tds meter to your system.
do you use colour changing DI rsesin?

[FragIt Dan]

Are you talking about a TDS meter? I don't know of anything that will measure ions in general. If you still have phosphate post DI, slow the water flow down or change the DI as it may be exhausted. DI works based on exposure time, so if you have a reservoir you need to put it after the DI and put a one way valve in between the DI and the reservoir. Used properly, you should be phosphate free.
Dan

[11purewater]

Are you on a well?

[SanguinesDream]

Originally Posted by FragIt Dan

Are you talking about a TDS meter?

Yes, that darn T didn't stick. TDS.

And I currently do not have a RO/DI unit but after testing the levels from the towns' RO/DI retailers, the best system is still high in phosphates and TDS. Unfortunately, I tested AFTER I got the cyano and ha breakout. So, a shopping I will go because you know there isn't anything more sexy than a great RO/DI unit. *heavily dripping with sarcasm*

So, looking at all of the upgrades that I need to do to my system, it seems that if I can go sumpless and skimmerless but have a great input of water on an every odd day basis, the RO/DI unit may be my best bang for buck. So looking at units on ebay, I'm wondering if the built in meters are worth the extra coin vs the benefit.

[gregzz4]

Originally Posted by SanguinesDream

I'm wondering if the built in meters are worth the extra coin vs the benefit.

An inline TDS meter is invaluable. Dual is nice for measuring both source and post-filtered water
Inline gives you the option of monitoring your filter media and checking output before you fill your storage container

Hanna makes a great dual inline that sells for $30 from BRS and $36 from J&L

Buy a bottle of cal solution and check it once a year, or when you suspect it could be off

[Aquattro]

IMO, if it's included, fine, but I wouldn't pay extra for it. Any meter will need calibration at some point. With properly maintained pre filters, flushing your RO membrane and running DI resin that indicates exhaustion with a color change, you'd be good for years. If the TDS meter is going to give you peace of mind, fine, but it's money you could put towards something else.

[craigwmiller]

I recently added a Dual Inline TDS meter to my system (previously using just a hand-held). I placed the two points after the RO membrane, and then after the DI.

The pre-filters don't really do much for TDS (which is measurement of much much smaller particles), leaving the membrane and DI resin doing the brunt of the work... Since DI resin is costly, knowing how efficient my RO membrane is operating is very important! I now can do a more serious flush of the membrane when the TDS post-RO is >5 TDS... and with the dual meter, I can quickly (seconds) have peace of mind that the post-DI water is still 0 TDS.


Using a hand-held checker getting measurements from the post-RO/pre-DI water is still totally possible - though somewhat tricky... It would take a Tee, check valve, and manual shutoff valve, letting you divert some water from the post-RO/pre-DI stream... you would need the check valve between the Tee and the DI though to ensure you don't get back-flush water from the DI into your Tee causing your reading to be skewed.

[gregzz4]

I should have elaborated on my setup
I have both a single and a dual meter
I measure supply water, post RO and post DI
FYI, I also have pressure guages on my supply and pre-RO to monitor the filters. You could say I'm a bit OCD

For the OP, as Brad stated, if it's included and is comparable to what I linked above, go for it

I only mentioned what I use as I like to keep an eye on most stages of my system

[Myka]

I like an inline TDS meter in one place - between the RO membrane and the DI resin so that I know how much TDS is going to the DI. This is a luxury though, and not needed. I like to use a handheld meter for product water. Make sure that any TDS meter that you buy is either self-calibrating when you dip it in calibration solution or it has manual calibration. All TDS meters are "factory calibrated" but do not buy a TDS meter that you can't calibrate afterwards because the calibration will wander off.

IF you buy a dual TDS meter, spend the extra few bucks to get the HM Digital DM2 as it has dual calibration where the DM1 has only one calibration screw for both probes which often do not read the same, so it is impossible to calibrate both probes properly. Or make sure whichever brand it is that if it has dual probes it also has dual calibration. The ones Greg linked to above are both the DM1.

I have fond that I can't rely solely on the color of color changing DI resin because I found the outside of the DI resin would all change color and I would dump it out to find the core of the DI resin still had plenty of color! So now when the color on the outside is all changed that's my red flag and I start testing product water until it shows 1 ppm, and then I change the DI resin. In my case, the DI resin often last another 4 months or so after the outside portion has changed color.

What is the TDS of your tap water? Phosphate level? Chlorine/chloramines?