Hi all,
Wife trying to convince me to get an under sink RO unit for 'clean' drinking water, was considering it from the point of view of the fish tank, am in D15 area and water has gotten very, very hard (all my water tests always read highest possible value). Just wondering if the water from these units can be used straight from unit or if they should be mixed with tap water. Also, if the RO water is used on it's own I assume you don't need to add the anti-chlorine/chloramine conditioners any more?


Thanks.

Hello;
You've raised an issue close to my own heart, having set up an R/O unit today!
I'll give you what I've been able to glean on the matter thus far and hope this can become an ongoing subject for all to contribute to.

The water from a Reverse Osmosis unit is completely inert and would need trace elements etc being added back to it, this can be done with products such as RO Right and Discus Preiis(spelling!) or I was shown a clever alternative to this...a 'tapping' is taken from the post pre-filter stage and is added back to the R/O water discharge via two 'Tee' unions. Now, the big problem here is that the water leaving the pre-filters would have to be controlled by a valve tap as otherwise it would all fail to go through the R/O membrane, taking the path of least resistance...but for this to be successful you would need an inline TDS meter to assess the water 'mixture' and be able to achieve the desired 'mix'.

I have been told that drinking R/O water is also a bit of a 'no-no' too, but I used it for both drinking and for making tea and coffee when I last had an R/O unit up and running when I lived in England...and I'm still here, so perhaps this can be taken further (no, not me being still here). :o) :o) :o)
And yes, you would no longer need to pre-treat your water for Chlorine etc (so long as you only use pure R/O water and not the 'mix' I'm suggesting could be a compromise solution).

Let's hope more Forum members can add to this discussion.

John

I have used Electrolyte balance and Discus Periis with my RO water.
There should not be a need to add a anti-chlorine/chloramine conditioner to RO water as the membrane should reject that size of a particle.
You really need to add in trace elements to RO water which will naturally buffer the pH level otherwise the pH level can swing widely

Darragh

Sorry to drag this post up from the dead. Ive been lurking here reading old articles/posts and finally got round to registering.

Does RO stand for Reverse Osmosis ??

Ive been using RO water for my community tank for about the last year !!
I have been treating it with Tetra AquaSafe water conditioner. Now theres somethign I dont have to add to it anymore

The tank itself has been up and running for 2 years, water changes are about 6-8 litres every week, more often if required.

Water params are (Tetra Test 5 in 1)
N03 - 50mg/l
NO2 - 0mg/l
GH - > 16
KH - Between 10 and 15
pH - 8

NO2 and NO3 readings confirmed with Nutrifin test kit.

Using the water, I have not noticed any difference in the aquarium compared to previous. Its been the perfect home for my colony of ever replicating guppies.

This has never been something Ive thought of before reading this post.
What sort of trace elements am I missing ?


Having said that I am about to aquascape it and intend on adding some live plants. This may be where the required elements will show my failings??

Having said that, in my aquascape plans there will be some fertilisers of some form (not fully researched) under the substrate.

Then again on water changes Im also adding Tetra Easy Balance Water Conditioner, a quick write up of this says "Adds the crucial vitamins, trace elements and minerals which are essential for a healthy aquarium"

In my ignorance and enthusiasm to keep this tank healthy, I may have been solving a problem I didnt know I had...

A tapping from before the RO unit will not be possible, as its there to remove the salinity from a salt based water softner.

[Edit]
Just to add to above, my bone to pick with the RO under sink tank...

it is only about 8 litres, and takes about 5-6 hours to fill.
When planning a water change I need to fill and condition the water in advance, otherwise I may find that there is no water left for other household uses.
Or if we have been using a lot of the water for cooking etc (sunday dinner, spud/cabbage/carrots etc.. , I can find that there is not enough water in the tank for a water change.