MichaelJ
Member
I have a household water softener system installed in our house. Its one one of those salt-based ones that replaces the calcium and magnesium ions from the city water water (which is considered very hard at around 20 GH) and replaces them with sodium ions - as far as I understand. All for the benefit of avoiding scale and lime buildup, use less soap and detergents etc. - it may release more metals from pipes and joints etc. than hard water. But anyway, the softener is hook up so everything that comes out of the taps run through the system (except for our irrigation system and outdoor hoses). The TDS of the water coming out of the softener (tap) is about 350 ppm, KH is around 10-11, GH “0” (unable to measure with test kit), Ph around 7.5. So if 10-11 KH is about 180 ppm then I assume a large chunk of the remaining 170 ppm (350ppm-180ppm) is from sodium? How much exactly I do not know.
When I restarted the hobby about 9 months ago I was given the advice that I should not be using the straight tap water due to the softener (sodium), but instead get an RO unit and remineralize the RO water to target specific KH,GH values and that is what I’ve been doing since (The RO unit claims 100 GPD and I am getting closer to 56 GPD partly due to being quite a bit lower than the of specified water pressure for 100 GPD…). Years back when I lived in an area with “better” water and no water softener I would just use straight dechlorinated tap water. Simpler times I guess…
Now with two 40 gallon tanks and a weekly 20% WC its been manageable, but I’ve realized recently that my RO water prep approach, fertilization level, bio load and possibly other factors beyond my understanding, that my weekly WC % is probably not enough. I want to up it to 40% a week, at least for a while. It already takes about 6 hours to produce the roughly 14 US gallon of RO water needed for the 20% WCs (7 gallon in each tank which holds a net volume of about 35 gallon ). Not to mention the waste from making the RO water (water is cheap and plentiful here in Minnesota but still…).
So, my question is the following:
Could I instead mix the softened (dechlorinated) tap water with RO water say 65% Tap / 35% RO, which would yield a KH of about 7 and remineralized to target my preferred GH (which is around 8) ?
With this approach I could reduce the time (and waste) to make the RO water by 30% and double my weekly WC %
A rough (and perhaps wrong?) approximation from my rudimentary understanding of the situation: The softener will leave around 45% sodium from the ion exchange which amounts to about 162 ppm for the 20 GH city water, which in turn leaves a residual of about 105 ppm (+ whatever sodium is in the city water already) after being mixed with the RO water (The RO water is 2-3 ppm… which is probably as good as it gets for the money).
Would the residual sodium be or become an issue for the fish or plants? If so, I could of course up the RO ratio, but how much would then be the question?
My livestock are tetras, rams and angles, ottos and mystery snails.
Both tanks are heavily planted with various crypts, various anubias, various swords and some vals.
Cheers,
Michael
When I restarted the hobby about 9 months ago I was given the advice that I should not be using the straight tap water due to the softener (sodium), but instead get an RO unit and remineralize the RO water to target specific KH,GH values and that is what I’ve been doing since (The RO unit claims 100 GPD and I am getting closer to 56 GPD partly due to being quite a bit lower than the of specified water pressure for 100 GPD…). Years back when I lived in an area with “better” water and no water softener I would just use straight dechlorinated tap water. Simpler times I guess…
Now with two 40 gallon tanks and a weekly 20% WC its been manageable, but I’ve realized recently that my RO water prep approach, fertilization level, bio load and possibly other factors beyond my understanding, that my weekly WC % is probably not enough. I want to up it to 40% a week, at least for a while. It already takes about 6 hours to produce the roughly 14 US gallon of RO water needed for the 20% WCs (7 gallon in each tank which holds a net volume of about 35 gallon ). Not to mention the waste from making the RO water (water is cheap and plentiful here in Minnesota but still…).
So, my question is the following:
Could I instead mix the softened (dechlorinated) tap water with RO water say 65% Tap / 35% RO, which would yield a KH of about 7 and remineralized to target my preferred GH (which is around 8) ?
With this approach I could reduce the time (and waste) to make the RO water by 30% and double my weekly WC %
A rough (and perhaps wrong?) approximation from my rudimentary understanding of the situation: The softener will leave around 45% sodium from the ion exchange which amounts to about 162 ppm for the 20 GH city water, which in turn leaves a residual of about 105 ppm (+ whatever sodium is in the city water already) after being mixed with the RO water (The RO water is 2-3 ppm… which is probably as good as it gets for the money).
Would the residual sodium be or become an issue for the fish or plants? If so, I could of course up the RO ratio, but how much would then be the question?
My livestock are tetras, rams and angles, ottos and mystery snails.
Both tanks are heavily planted with various crypts, various anubias, various swords and some vals.
Cheers,
Michael