TDS Readings

[Ocean Images]

Hummmm, I just purchased my first TDS meter (thanks AJ) I was very curious to make a couple sample measurements. I measured my "older" Ocean Reef RO unit that I use for drinking water at home.......011 was the reading, I didn't think that was too bad considering the membrane is about 3 yrs old.
Next I measured my Spectra RO unit with additional DI filter, the reading was 053 and this filter is only a year or so old.
My question is; if you were to get a reading of 053 what would be the first plan of action to lowering this number. I am guessing the membrane would be the first solution but as we all know its the most expensive also.
:(

[ajx22]

Originally posted by Ocean Images
Hummmm, I just purchased my first TDS meter (thanks AJ) I was very curious to make a couple sample measurements. I measured my "older" Ocean Reef RO unit that I use for drinking water at home.......011 was the reading, I didn't think that was too bad considering the membrane is about 3 yrs old.
Next I measured my Spectra RO unit with additional DI filter, the reading was 053 and this filter is only a year or so old.
My question is; if you were to get a reading of 053 what would be the first plan of action to lowering this number. I am guessing the membrane would be the first solution but as we all know its the most expensive also.
:(

When were your sediment and carbon filters replaced last? They should be replaced every 6-months to help protect the RO Membrane. The RO Membrane should last 2-3 years - under well prefiltered situations. As soon as these prefilters get exhausted, then they allow suspended particles to deteriorate the RO membrane at a much faster rate.

When was the DI cartridge replaced? This is the filter that removes the final amounts of TDS - and if it is exhausted...then you will definitely see an increase of TDS in your readings!

I have 0.00ppm of TDS out of my RO/DI unit with fresh filters - and I replace my sediment and Carbon every 6-months - and I change out the DI as soon as I get readings in excess of 5ppm.

You should also consider adding a Membrane Flush Kit if you don't already have one.

The RO/DI Super-Guru (Marianne) might have something to add to this as well...but from what I have learned from her...the above should be correct. :D

You can also read the info provided in this link to learn a little more about the way a RO/DI filter works.
RO/DI Information (http://www.aquariumpros.ca/rodi_info.html)

Depending on when you last replaced your filters - I would suggest that you purchase a new set of prefilters + RO Membrane + DI cartridge (less any that have been newly replaced) + a flush kit to protect your membrane investment.

HTH,

[ajx22]

Also...what is the TDS reading of your (unfiltered) tap water?

[aquafx]

It sounds like the membrane is no good. If you let the carbon exhausts then the chlorine will "eat" the membrane. There are other causes of membrane failure too.

Anyway. your question. AJ (or should I say Grasshopper) you are a good student.

What you will see is the membrane knock down the TDS to 90% or better of the incoming water TDS. The DI should take it to 0.

Sorry got to run, let me know your thoughts!

[Ocean Images]

My tap water reading was 385.
I will cure this problem as soon as I get back from vacation :dance:
I am gone for a week, it sure is hard leaving my tank and it was even harder finding a "tank sitter" :D
See you next weekend
:cheers:

[ajx22]

No problem Bill...just let me know what you need!

Also...in respect to the prefilters...use care to ensure that you are using the right sized filters:
Sediment = 1 Micron
Carbon = 2 Micron
If you use larger rated filters...you are letting more of the bad water contents reach your TFC (RO) Membrane - thus defeating the whole purpose of the prefilters job!

Enjoy your vacation!!! :D

[Ocean Images]

I replaced my DI filter today, after approx 15 minutes of running my TDS readings fell from 59 ppm to 1 ppm
Thansk again AJ for the TDS meter, I will be able to monitor the performance of the RO unit before it gets out of hand.
:cheers:

[aquafx]

Ocean Images

One added thought, the rate at which your DI exhausts will give you an indication of how well your membrane is preforming.

Also, a better way is the check the TDS after the membrane. If you are going to post that, please post the raw water TDS also.

[Ocean Images]

I will test the TDS after the membrane and before the DI filter. I am curious to see the resluts.

Thanks, Aquafx