Why does the tds raise with Novaqua conditioner

[Devildoc]

Ran some rodi this morning for a WC when checking the TDs with my meter I noticed it was high for me (37) time for a new membrane I know. Well I added 7.5ml novaqua water conditioner to 15 gallon rodi water but instead of making the TDs drop they rose from (35 to 70tds).

What would make it do that? Isn't it supposed to lower TDs?

I haven't added salt yet so the water is mixing as just rodi at the moment. My mixing station is a 30 gallon glass tank I had spare.

 

[AZDesertRat]

A conditioner is not going to lower TDS, it can't magically disappear. Two things remove dissolved solids, reverse osmosis and deionization. Carbon removes a tiny amount but not much.

Whay are you adding a conditioner to RO/DI water? This is counterproductive since you have paid good money to remove the contaminants only to put them back in as you have seen. The conditioner has chemicals dissolved in the solution which do not remove anything, they only mask or bind contaminants so they are not as toxic but they are still there.

What is your tap water TDS, RO only TDS before the DI and your final RO/DI TDS taken directly from the unit, not out of your storage or mixing container? Also make sure your TDS meter is clean by triple rinsing btween each individual test with fresh RO/DI or if you suspect it is bad a jug of distilled water. It doesn't take much to foul the meters probes and skew the readings.

 

[Devildoc]

200 out of the tap , 48 out ro , 27-32 out of di.. Honestly I added thinking it would do what you said it wouldnt . I have only rinsed when I first go the meter. Will head to the store and get some distilled water though

 

[Randy Holmes-Farley Verified Community Expert]

The Novaqua conditions claims it


"Detoxifies and helps buffer tap water while adding electrolytes and a protective body slime to ease stress during acclimation or illness."


Among other ingredients that boost TDS, electrolytes will, by definition, raise TDS. They are essentially ionic salts and are conductive.

TDS is never a measure of the suitability of water for a reef tank. It is only ever a measure of the "saltiness".

 

[AZDesertRat]

Wow, if the TDS out of the RO is 48 then your membrane is not doing much, thats only around 75% efficiency when it should be around 96-98%. Your DI life has to be dismal since it is having to make up for a poorly performing RO membrane. I would expect to see a RO TDS or maybe 2-3 if the membrane was doing as it should.

TDS or better yet conductivity is the best measurement we have in the hobby for the suitability of RO or RO/DI water since hobbyist grade test kits and meters are not very accurate in ultrapure waters.

 

[Randy Holmes-Farley Verified Community Expert]

TDS or better yet conductivity is the best measurement we have in the hobby for the suitability of RO or RO/DI water since hobbyist grade test kits and meters are not very accurate in ultrapure waters.

Is that in response to my statement that

"TDS is never a measure of the suitability of water for a reef tank. It is only ever a measure of the "saltiness". ?

Knowing you, I'm sure we both agree, but perhaps to clarify, we can agree on:

TDS is not a measure of the suitability of water for a reef aquarium, but rather for how well an RO/DI is functioning. If we conclude the RO/DI is functioning well, then we can likely conclude the water is OK. But the raw TDS number neither guarantees adequate purity if low, nor does it necessarily indicate unacceptability if high, since VERY high TDS water can be fine (take NSW, for example) and low TDS water may not be (RO/DI water stored in a copper pipe, for example).

 

[AZDesertRat]

Yes, I agree. Since TDS is not a measurement of anything specific, only that something electrically conductive (solutes) is present, it does not tell us if it is copper, silicates, calcium or whatever. But, if we are using a RO/DI and not tap water we should have a reasonable expectation that 0 TDS on a good quality meter is about as pure as we are going to see. Another thing I always recommend to anyone on a domestic well, as does the EPA, is to have the water tested for known or suspected contaminants in the area. A basic well scan is pretty inexpensive and individual things like fuel byproducts, herbicides and pesticides can be added at a reasonable cost if the area has been farmed in the past. It is really nice to know what you are starting with and it can be a life saver.