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Using Cation Exchange Resin To Soften Water?

11K views 21 replies 13 participants last post by  Edward  
#1 ·
It's time for another Good Idea / Bad Idea.

Ion exchange resin - Wikipedia, the free encyclopedia

ADA makes a product they call the softenizer. It uses these cation exchange resins to soften the water. The ADA catalogue states that it should be dialed down via a "faucet" because it works rapidly. It works by attracting Ca and Mg particles and replacing them with Na. I wonder if anyone feels the Na could be harmful to plants?

If it sounds feasible, the nice thing is that unlike peat in the filter it can be recharged by soaking it in a salt solution.
 
#5 ·
Cation Exchange Resin could have 2 potential benefits:
1. Reduce tap water hardness for some plants prefer low GH (for example Tonina)
2. There are some places that Mg in tap water is too high.
This can cause Ca/Mg ratio to be unbalanced. Cation Exchange Resin can "reset" the ratio and let you restore the elements with right ratio.
 
#7 ·
But then it's ADA so it's got to work. ;)
I know it's dangerous to believe something like that, but that's exactly what was going through my mind. :) I've used their other products and the ones I've used work really well.
 
#12 ·
No, that's not it. It's in the new ADA catalogue. It's a piece of glassware that houses those cation exchange resin beads. Either way, it doesn't sound like something useful to us planted aquarists.

Regarding the water softeners: You can get now also pellets which are using potassium instead of the Na.This works better for the plants and the waste water facilities.
Do you have a link to some info on these? I don't mind using peat for the time being, but it would be nice to have a reusable resource for softening water.
 
#13 ·
You know, RO isn't that expensive. On a per-gallon basis it's next to free. It's sort of like getting pressurized CO2. There's a large up-front cost, but operation is simple and it basically gives you the ability to make whatever suits your fancy - very nice if you're trying to breed fish, keep "more difficult" plants, and such.
 
#14 ·
I totally agree with guaiac boy. I've got a 50gpd unit that cost ÂŁ60 and only needs the carbon and sediment filter replacing every 6 months. They cost less than a tenner to replace. The only problem would be if i was on a water meter as for every litre of product water you get, you waste about 5 litres (except my unit's waste water feeds into my pond and gives them a top-up).
 
#15 ·
The potassium pellets are for house water softeners. As a DIY, I wonder if you could modify an inline water filter for the sink to hold the potassium pellets? You could have it on a separate line that you use only for the aquarium. All of the mod and plumbing is something almost anyone could do. I just don't know if it would work.

Aaron, Bigstick and other "difficult" plant growers... has it been your experience that kH or Gh makes the difference with hard plants? This ADA or house softener thing won't touch the kH. You need RO for that. Also, there one drawback to RO besides cost, not everyone has enough water pressure to make it work without a booster pump. That means more money.
 
#16 ·
Ah, good to know it won't touch the KH. Lower KH is what I'm after. The lower it is, the better most of my plants grow, expecially the 'difficult' ones.

I've considered RO and I'm in an apartment in someone's home. We're on well water so as you said, it gets more expensive having to buy a unit with a pump to increase pressure. The other thing I don't like about RO water is the wasting of so much water. If I had a home I would setup a rainbarrel or four, but I have to work with what I have for now.

I'll stick with adding some peat to the filter for now. I know it's not the greatest to be overharvesting the bogs too, but at least a little bit goes a long way.
 
#17 ·
In the last place I lived, the owners had a water softener. They let me use KCl instead of NaCl. This worked great to soften the water and add K also.

I don't know much about the ADA softening system, but it sounds like you would have to "recharge" it by hand. This sounds like a huge pain in the butt.

Like others said, an RO system is a great way to soften your water - especially since you want to lower the KH. I picked up a RODI on ebay for $100. A little later my brother picked up the same one for $65 (including shipping).
 
#18 ·
Arron, You could also remove the carbonate using an acid. TWood had a good post about his technique. It involves using muratic or HCl in small amount until you get the desired hardness. The nice thing with that is the carbonates are converted to water by combining with the extra H+ from the acid. You would get some added Cl from this but the way I understand it, the Cl is in a free ion form and not really in the same "place" as the fish/plants. Sulfuric acid is also an option and you get more bang for the buck as far as the ratio of H to S and the S may be less of an issue to the plants/fish. If your water is very consistent, once you figure out how much acid to use per gallon of water, its easy after that. You could easily mix up a 5 gal bucket or a trash can full whenever you want.
 
#20 ·
Jeez I have used water that goes thru my home water softener for years.
I use a blend of about 50/50 soft and hard. I have never noticed any problems. Have bred Angels, Corys and Discus using this water. I just recently started my 1st planted tank but everything seems OK so far. I have no way to store RO water nor the inclination to do so.
Gene
 
#22 ·
Hi
Ion exchangers were used successfully for aquariums before RO time. Why? There are two types of resins. Cati and Ani. Cati can be regenerated by NaCl or HCl. Ani is regenerated by NaOH.

House water softeners are cati regenerated by NaCl. Ca and Mg is removed from water and replaced with Na. This removes GH but adds large unnatural amounts of Na which increases conductivity significantly and creates deficiency problems in plants and fish.

Cati regenerated by HCl removes Ca and Mg and adds relatively strong acids (depending on GH level) back to the water.

Cati regenerated by HCl and then connected to Ani regenerated by NaOH produces water 10x cleaner then distilled water and 100x cleaner then RO. But, the cost and dealing with concentrated HCl and NaOH for regeneration is not exactly home friendly process. I have done this before RO time and can tell you, RO is the right choice. RO is much cheaper, easier and very predictable.

A good system is High-Flow RO. It does produce water with small amounts of Ca and KH passing through which is perfect for our aquariums.

Thank you
Edward