# Mixing RO and well water



## maxw47 (Jan 22, 2012)

So, let me start off by saying that I want my water at a Ph of 6.8 and a GH of 2-4 (for fundulopanchax gardneri killifish). But I have a slight problem. I have well water with a Ph of 8.2 and a GH of 7-8. My theory was that if half of the water is RO, then my GH would be 4ish and my Ph would be somewhere around 7.8 (my guess). Obviously, I can't get my Ph below 7 by adding RO. So how could I keep my GH at four (by adding half RO), but get my Ph to 6.8? Originally I was thinking about putting in a piece of driftwood, but that wouldn't allow me to lower it to 6.8 exactly. How should I go about getting my water to that point? Really, the Ph could be in the range of 6.5 to 7, so it doesn't need to be exact. Should I try the driftwood? Thanks for any replies in advance.


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## Captain Jim Dandy (Oct 30, 2011)

*Making tea*

Have you considered filtering peat through your water sample? Without fish, now.. Take maybe 5 gallons of your water and take your readings. Filter plain (no additives like ferts) peat moss into your five gallon batch for maybe 12 hours and again take readings. I'm talking about a tea bag size of peat. Either continue to run peat into same 5 gallons or double your peat "feed" and run till desired ph is reached. You can of course use smaller test samples. See if you manipulate your water some this natural way. I would not get involved wiyh your "magic ph adjustment chemicals."


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## Byron (Mar 7, 2009)

The pH will tend to lower due to the biological system in an established aquarium. But knowing the KH (carbonate hardness or Alkalinity) of the well water will tell us how slow/fast this should be. Attempts to lower the pH if the KH is high enough to buffer it will be useless.

Byron.


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## maxw47 (Jan 22, 2012)

My KH is at 10. But if I were to mix with half RO water, then it would be 5 (assuming that RO's KH is 0). 5 is pretty workable right? I thought about peat, but I have heard that it is a little unreliable because it wears of. But for all I know driftwood could be the same. Any other ideas? Thanks guys!


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## Byron (Mar 7, 2009)

maxw47 said:


> My KH is at 10. But if I were to mix with half RO water, then it would be 5 (assuming that RO's KH is 0). 5 is pretty workable right? I thought about peat, but I have heard that it is a little unreliable because it wears of. But for all I know driftwood could be the same. Any other ideas? Thanks guys!


Are these numbers degrees, or ppm? If degrees, then a KH of 5 will still buffer, I can't say how much exactly.

Peat, dry leaves and wood will all assist in lowering GH and pH. Peat will exhaust its capacity to do this depending upon the amount, the GH/KH, and time.

My preference to soften water and lower pH is by dilution with "pure" water which can be rainwater/snowmelt, RO or distilled.


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## Captain Jim Dandy (Oct 30, 2011)

*Softening water*

Listen to Byron- he's expert at this. Your kh at 10 is harder than mine at 7. I would have to suggest the peat wouldn't be enough to change to what you want for killifish. Maybe Byron can help us both here. My water pressure is too low to even run a RO system so I have given up on apistos for now. Even angelfish are on on the edge of health for me. CJD


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## Byron (Mar 7, 2009)

Captain Jim Dandy said:


> Listen to Byron- he's expert at this. Your kh at 10 is harder than mine at 7. I would have to suggest the peat wouldn't be enough to change to what you want for killifish. Maybe Byron can help us both here. My water pressure is too low to even run a RO system so I have given up on apistos for now. Even angelfish are on on the edge of health for me. CJD


Peat will do it, but it may take a bit of it. I've never used peat, luckily having soft water run out of my tap--and by soft, i mean it is equal in GH and KH to streams in the Amazon. My issue is having to add hardness for the plants.


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## maxw47 (Jan 22, 2012)

Hey, I just had and idea, although it might get a little expensive. What if I were to take pure RO water, add in trace minerals (I have seen numerous products that are labeled like this). Then, add peat to get a ph just below 7. Would this work? Or should I not add peat and just keep RO with a little bit of trace minerals to get a gh of around four? Thanks!


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## Byron (Mar 7, 2009)

maxw47 said:


> Hey, I just had and idea, although it might get a little expensive. What if I were to take pure RO water, add in trace minerals (I have seen numerous products that are labeled like this). Then, add peat to get a ph just below 7. Would this work? Or should I not add peat and just keep RO with a little bit of trace minerals to get a gh of around four? Thanks!


Totally RO water should have zero or near-zero GH (and KH), and the pH likely just below 7, say mid-6 range. As the tank's biology establishes the pH will lower down to 5 or below if you let it. Which is fine for some fish, not for others. And you will have to add hard minerals for the plants. Some fish would find this too soft too, again depending upon species. As the tap water is free and to hand, it would be easier to mix some in, but you can experiment with this to see the numbers. Additives can get expensive too. I use Equilibrium solely due to plants to provide calcium, magnesium and potassium.


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## maxw47 (Jan 22, 2012)

I found a product by Kent called Kent R/O Right. It is an RO supplement. I think I will order it and experiment a little with some RO water. Will having virtually no buffers leave me vulnerable to major ph swings? How could I avoid that? Thanks!


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## maxw47 (Jan 22, 2012)

Wait, I just saw the equilibrium that you were talking about and it says that it helps maintain a buffering system, it is ideal for remineralization of RO water, it's good for planted tanks (I plan to have all 3 killie tanks fully planted), and it is a dollar cheaper for 50g more. So now I think I am all good. I'll use pure RO water, add the correct amount of equilibrium, and enjoy. Sound good? Thanks for all of your help!


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## Byron (Mar 7, 2009)

> I found a product by Kent called Kent R/O Right. It is an RO supplement. I think I will order it and experiment a little with some RO water. Will having virtually no buffers leave me vulnerable to major ph swings? How could I avoid that? Thanks


Don't know this product myself. The pH depends upon the resulting GH, KH and biology. Each aquarium can be very different.



> Wait, I just saw the equilibrium that you were talking about and it says that it helps maintain a buffering system, it is ideal for remineralization of RO water, it's good for planted tanks (I plan to have all 3 killie tanks fully planted), and it is a dollar cheaper for 50g more. So now I think I am all good. I'll use pure RO water, add the correct amount of equilibrium, and enjoy. Sound good?


I don't think Equilibrium buffers, Seachem suggests using their KH buffer as well [I don't]. It just adds the hard minerals to raise GH.


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## maxw47 (Jan 22, 2012)

Hmm, I just read this in a Drs. foster and smith catalog under the product. I'll look into it more and see if that is true or not, but a kh buffer is probably a great idea even if equilibrium already buffers a bit. Thanks!


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## Byron (Mar 7, 2009)

maxw47 said:


> Hmm, I just read this in a Drs. foster and smith catalog under the product. I'll look into it more and see if that is true or not, but a kh buffer is probably a great idea even if equilibrium already buffers a bit. Thanks!


If you're going to be using all RO water, including for water changes, KH may or may not matter. You don't want to start dumping unnecessary substances in a fish tank.;-)

My water has zero KH and i add nothing to buffer, and in 20+ years I've never had issues with pH.


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## maxw47 (Jan 22, 2012)

Good point. I read a more detailed description of the equilibrium and it says it "also aids in maintaining a complete buffering system." With that said, I will not add any kh buffer stuff. If I do notice anything unusual (spikes in ph of any sort), maybe I'll look into it, but I will take your advice for now. Thanks for all of the advice!


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## Varkolak (Jun 9, 2012)

I tried this R/o water with well water thing xD didn't work for me - spiked my ph to around 8 from 7.6


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## Byron (Mar 7, 2009)

That is a good caution. Whenever one is mixing waters and substances, the "expected" result is not always guaranteed, as other chemistry factors that we may not even know are there can affect things. Always go slow, and not with fish in the tank where water is being mixed until you know what that will do.


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