A Community and Forum For Aquaponic Gardeners

Water hardness and RO filters

Considering our especially hard water, I'm surprised that there doesn't seem to be a discussion about water hardness in the AZ group (unless I missed it).

From what I've read most people in general (not locally) do not like RO filtered water, but people with really hard water (like us in Scottsdale, pH 10+, hardness of 1100 ppm with EC meter, still waiting for my KH/GH test kit to arrive) should use an RO filter, right?

Is that what most people in the valley do? Anyone have specific recommendations for RO filters?

Thank you.

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Replies to This Discussion

Permalink Reply by Tony L on November 5, 2013 at 5:12pm

Hi Vlad, I really appreciate the clarification, that chart is very helpful and what you said makes sense.

When I said special, I meant more scientific than "magical". For instance, perhaps hydroponic nutrients are absorbed at a narrow pH band than aquaponic nutrients. As you said, how plants grow without soil is how plants grow without soil, but are all nutrients the same?

Permalink Reply by Vlad Jovanovic on November 5, 2013 at 6:33pm

Well, in a big and meaningful way...yes. They are absolutely the same. This is speaking in terms of plant physiology. Plants can ONLY uptake essential elements when those elements are in there most basic ionic form. A plant cares not whether the essential element was obtained through dissociation of a mineral salt, or the bacterial breakdown of complex organic matter. So in that regard, no, there is no difference.

However, if you go to the pics section of my page most all those tomatoes and peppers and whatnot that you see were grown in a pH of 8 or so. I AM IN NO WAY ADVOCATING THAT THIS IS THE NORM, as I have a VERY specific and unique set of circumstances in my system. I've been using 6 different strains of very specific bacteria isolated from soil samples and then cultured in a lab to solubilize plant essential elements bound up in the fish effluent.

This is probably not the thread to get into it...and I've avoided talking much about it thus far because it pretty much goes against everything I've thought/written/expressed before regarding what a "good" pH is. I've generally advocated pH in the lower 6's (and publicly still do and will continue to until I can be certain of what exactly is going on...and why)...

Besides, I'm not the type of guy to go tooting any horns or singing praises prematurely (I'll leave that to others), but in short, I believe that the specific microbiology (exudates and all) used a "dual root zone" set up is helping to foster pH "micro-climates" in the rhizosphere and allowing me to get away with "things doing really well" even at such "cruddy" system pH levels...http://community.theaquaponicsource.com/group/fish-less-systems/for...

So in that regard, looking at thing from a bit of a different perspective and within a very particular context, perhaps a (somewhat skewed) case can be made that 'the pH band in which mineral salts in a microbially inert system is narrower than in an AP system that is teeming with microbes...

Permalink Reply by Tony L on November 7, 2013 at 10:05am

Hey thanks a lot for taking the time to explain that to me, clearly I have some learning to do.

I just finished reading that thread, it's nothing short of brilliant. I'm designing a system now so I may attempt it.

I've been considering setting up my media bed so it is completely modular---that is there is no media in the bed itself, but all the media is in cubic mesh (?) containers that fit side by side together in the bed. It would be harder to install but it would allow for easy maintenance, just pull out the cubes to clean out roots, etc. And then if the bed every does need serious cleaning out it would make it easier. Maybe the roots would just all get tangled together and it wouldn't help, I'm not sure.

I saw something like this on youtube but I can't find it now. It almost looked like they were using shopping baskets. However, it was with larger media and a constant flow bed. I'm considering smaller media and a flood and drain.

Thanks again, looking forward to your updates. Impressive yields!

Permalink Reply by Jim Fisk on November 14, 2013 at 8:03am

I too was no longer concerned with ph as all was well. That is until I introduced 50+ trout fingerlings to their new home and lost 30+ in 2 days. All was perfect save for the ph which had gone acid. I placed about half a cup of wood ashes in each grow bed under the inflow and the results spoke for themselves. Not a single loss since and the ph went neutral. Another lesson learned the hard way that I won't soon forget.