Reverse Osmosis

[Lonny Harper]

I've posted this question in a couple forums, I'm looking for more input.  What about reverse osmosis.  It would be at least a $200 investment.  I live in Southern California with horrible city water.  I don't have any other options.  Should I deal with the city water and treat it for all the bad stuff, or should I start with a clean slate and add the missing nutrients?  If I add the missing nutrients, what and how much?  Any help would be appreciated.

[Kobus Jooste]

Reverse osmosis water will be pretty much the dsame route as rain water, which is typpically advised against but possible.  I run a rain water unit and have seen some major issue, but if you know that they are there, you already have travelled some way towards solving your problem.

 

Here is what I have experienced and what I do about it.

 

Rain water and purified water typically have almost no alkalinity.  You will have to add this.  It is not a problem, as you will use calcium or potassium bicarbonate in small amounts in your make-up water or system's sump, but make sure that you trickle it in because it could affect pH.  What I often do is adjust the alkalinity in the make-up water first, and then see where the pH is.  If it is too high, I try to bring it back to safe or desired levels with the correct acid of your choice.

 

Any alkalinity above 50, up to about 120 should keep the pH stable. 

 

The pH of treated c/ rain water is usually still OK, but tends to be acidic and you should bear this in mind when the system is set up - it may not be ideal for bacteria without adding some alkalinity and cycling could be slower.

 

In terms of nutrients, the fish food should really contain a good deal of what you will need.  Trace elements are just that - needed in minute amounts only.  I have added small volumes of trace elements in the past, but once I got my bouncy pH under control and the system matured, it is much better.  If your system is media based, there will be a gradual build up of nutrients in the system and my experience is that although things may start off a little slow, it balances out in the end.  Take a look at the abstract below to get an idea of what your AP system water can look like after operating with "sterile" water and good food:

 

PRELIMINARY EVALUATION OF ORGANIC WASTE FROM TWO AQUACULTURE SYSTEMS AS A SOURCE OF INORGANIC NUTRIENTS FOR HYDROPONICS

 

J.E. Rakocy, D.S. Bailey, R.C. Shultz, J.J. Danaher 

 

Abstract

 

Aquaponic (AP) and greenwater tank culture (GW) systems have been developed at the University of the Virgin Islands for the intensive production of fish. Aquaponics is the combined culture of fish and hydroponic plants in recirculating systems. Greenwater tank culture utilizes a mixed suspended growth process involving autotrophic and heterotrophic bacteria and phytoplankton for water treatment. Large quantities of organic waste are removed from these systems daily. This organic waste is a potential source of inorganic nutrients for hydroponics. Samples of AP and GW sludge were continuously aerated for 29 days to facilitate mineralization. EC increased from 4.6 to 6.0 mS/cm (3200 to 4200 ppm TDS) in AP sludge and from 1.8 to 3.4 mS/cm (1260 to 2380 ppm TDS) in GW sludge. Thirteen nutrients (Ca, Mg, K, NH₄, NO₃, PO₄, SO₄, Fe, Mn, Zn, Cu, B and Mo) were compared to a standard hydroponic lettuce formulation (Resh, 1995). Final concentrations of six AP nutrients and eight GW nutrients exceeded standard hydroponic values while concentrations of seven AP nutrients and five GW nutrients were less than standard hydroponic values. Na and Cl concentrations in AP and GW sludge exceeded the recommended values for hydroponics. Hydroponic nutrient formulations derived from aquaculture waste may require dilution, supplementation and source material (fish feed) without salt.

 

Other methods of keeping pH and alkalinity in check (that I have not tried) is adding small amounts of shell grit, aragonite, coral sand or crushed sea shells to the system in a bag that can be removed if the pH goes up too far.

 

I do not know what your municipal water supply looks like, but I hope the bits above give you some idea of how your system may behave with RO water

[Johann]

The way I understand RO will take everything out of the water including all the nutrients, which is vital for the fish.

http://www.lowes.com/pd_152246-43353-WHED205_0__?productId=3130911&...http://http://www.lowes.com/pd_152246-43353-WHED205_0__?productId=3...

[Johann]

I would think a under the sink water filter like the link I gave before would be better, because the fish and system would need the nutrients.

Along the coastal area I would not use rainwater and if you use it check the salinity of the rain water. It is not that the salt will evaporate from the ocean, but it is the sand / sand dust that is covered with salt that is carried by the wind from the beaches and get deposit all over the places and when it rains in the winter( only time) the sand / sand dust releases the salt into the water.

I used to live in Long Beach and the city water was bad back then.

Johann said:

The way I understand RO will take everything out of the water including all the nutrients, which is vital for the fish.

http://www.lowes.com/pd_152246-43353-WHED205_0__?productId=3130911&...http://http://www.lowes.com/pd_152246-43353-WHED205_0__?productId=3...

[Richard Wyman]

You can buy a fertilizer to add nutrients back to RO water here, http://www.greenleafaquariums.com/aquarium-fertilizer.html, and also Chelated iron.  ( I hope its ok I linked it , its just a place I found it)

[Homefire]

Hi Lonny,

I agree with Kobus on RO; it's about same as rain water.  I do great with rain water; it comes down at about pH 6.0, I buffer it with limestone chips to 7.0. 

My RO puts out about 4 GPD.     How big is your system to be?  I looked over some of your posts but didn't see it.

I used some 20 to 30 G. RO water in my 90 G. system before i got rain water set up. 

 

No need to feel swamped by the technicallities of Aquaponics.  Just start and the system will teach you.  This is my first year and it all becomes clear as you do it. 

 

I spent quite some wasted time with bell siphons.  We are dealing with Fluid Dynamics and Chaos Science here.  Siphons just  can't be counted on beyond a few thousand cycles.  I've gone to the perforated stand pipe and timed pump method.

As for minerals I used kelp, worm tea, aerated compost tea and the minutest hint of Maxicrop with Iron as a foliar spray.  But as Sylvia cautions, one wants to be careful with iron. 

 

I'm calling my system a Vermaponic system since i expect the worms will be my primary souce of Nitrate.  Fish may be an option for later if i feel confident managing them.  My plants couldn't be better and the water chemistry is stable. 

 

Let us know how it goes,

 

Hf 

 

 

 

[Lonny Harper]

Johann, I'm gonna look into that some more.  I have a whole house filter that runs water through a carbon filter and a softener.  The only problem is that the softener puts sodium into the water.  I don't think there is any water conditioner that deals with this.

 

HF, I have a 10X20 green house.  I'm setting up a 550 gallon fish tank (outside the g/h), 450 gallon sump with  a hybrid grow system consisting of approximately 75 sq feet of 12 inch deep media filled grow beds, a dozen strawberry towers, and 30 flood and drain buckets.

[Johann]

You could tap into the line, between the house filter and your softener.

Lonny Harper said:

Johann, I'm gonna look into that some more.  I have a whole house filter that runs water through a carbon filter and a softener.  The only problem is that the softener puts sodium into the water.  I don't think there is any water conditioner that deals with this.

 

HF, I have a 10X20 green house.  I'm setting up a 550 gallon fish tank (outside the g/h), 450 gallon sump with  a hybrid grow system consisting of approximately 75 sq feet of 12 inch deep media filled grow beds, a dozen strawberry towers, and 30 flood and drain buckets.

[Lonny Harper]

The filter and softener are all one unit.  I don't know which it goes through first.  I'm gonna do some tests on my water and try to figure it out.  I think if I can get a handle on the chloramine, I will be okay.

[Paul Westberg]

Lonny: According to Tilapia Mama (San Diego) you can take out the chloramines with vitamin C. It is available @ Costco in pill form cheap. I just use lemons as it helps with the alkilinity. Sounds like we are dealing with the same problem. Would you please stay in touch and let me know what ends up working for you? Thanks, Paul

Lonny Harper said:

The filter and softener are all one unit.  I don't know which it goes through first.  I'm gonna do some tests on my water and try to figure it out.  I think if I can get a handle on the chloramine, I will be okay.