r/o water reading of 43

I recently moved my r/o unit from one are of the house to another and figured i would check the tds reading when i went to the lfs today. It was 43 Its a 4 stage ro/di. I have had it running at the house for a little over a year ago. I had the lfs check the tds about 2 months ago and it was 0 at that time. I changed 3 of the filters a few weeks back, the only one that has not been changed ever is the membrane. I have noticed both of my anemones recently retracting (curling into a ball) almost every night. They come back in full the next day, but this is not normal for them to do. Is there any chance by adding this 43 tds as top off water would affect them?
The only other change i have done recently was changing the carbon and GFO on monday night. I change both GFO and carbon the 1st of every month. Now this month i did add a little bit more gfo and carbon than i normally do, approx 10-20% more. Is there a chance this extra carbon or gfo could cause the nems to curl up?

Any idea or thoughts???

Thanks!

 

To know anything about your RO/DI you need three TDS readings not just one. What is your tap water TDS, RO only TDS before the DI and your final RO/DI TDS?
What are you testing with and what are you testing in? A dirty glass or container will give you false readings just as a dirty or miscalibrated TDS meter will.

If you don't own a handheld TDS meter you should, its the only way to know if you are producing good water and tells you the condition of both your RO membrane and your DI cartridge or resin. They are only $20-$25 for a high quality temperature compensated model like the HM Digital TDS-3, TDS-4TM or AP-1 and are worth their weight in gold. Do not waste money on the inline variety as they are not as accurate since they are not really temperature compensated and they limit you to two readings, usually the RO only and the finsihed water but again you need three readings including the tap water so have very limited value for the same $25 or so.

Without knowing your tap water quality its hard to say if a TDS of 43 is really bad. If it were only calcium it wouldn't be much of an issue but it could be nitrates, phosphates, silicates, arsenic or any number or combination of things. Without knowing the RO membrane condition (calculated using the tap TDS and the RO only TDS) you don't know if that 43 is a result of a bad membrane or exhausted DI resin releasing all the weakly ionized substances like the above phosphates and silicates.

I think you get the idea. A RO/DI is not a simple plug and play device, they require a minimal amount of maintenance and some monitoring which takes very little time and not much expense but they will last a long time when properly taken care of.

 

Thanks for the reply AZdesertrat!
I will be buying a good tds meter to check everything you said above. The 43 was read at my LFS and I know it is calibrated because i had them check the water they sell and it read 0. My tap water here reads 92 tds but not sure about the individual levels of each.

As far as maintenance, is there anything else i should be doing besides flushing the membrane?

 

What did you use to take the water to the LFS? Containers and how you prepare and clean them can make a huge difference.

You really need to read it from the source and not a container if possible or make sure the container is sterile.

Flushing the membrane has little if any proven value, it really only gives you a warm fuzzy feeling if anything. Maintenance consists of monitoring the TDS, checking the pressure drop of headloss, regular 6 month filter replacements and disinfection and maybe monitoring for chlorine breakthtru if you intend to stretch filter changes past 6 months. A TDS meter and pressure gauge are your best friends with a RO or RO/DI system.