# distilled water to lower pH?



## grannyfish (Jul 14, 2012)

Is it ok to use bottled distilled water mixed with tap water to lower pH? Is reverse osmosis water better or the same? I cannot find a source of RO but I can get distilled water anywhere. My 10 gallon aquarium water is 7.6, the GH is 6 and I would like to keep species that prefer lower pH and soft water.

If distilled is ok, what ratio to tap water should I use when making 20% water changes? 

Any other advice?


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## AbbeysDad (Mar 28, 2011)

First, I am no expert as I'm still learning about pH and hardness.
You would think that mixing RO, DI, RO/DI, distilled or rain water with tap or well water would lower pH... and it does initially. However, buffering will often bring pH back to previous levels. You'll need to use pH adjusters or materials like ground coral to maintain an acidic pH of your otherwise neutral/alkaline 7.6 water.


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## Olympia (Aug 25, 2011)

Well, if your kH is low initially the RO/distilled will lower it more.. However if the kH remains high even after mixing then the pH will go back up again. 
If you can figure out your kH, that would be helpful... 
Crushed coral will raise hardness and kH, and therefore raise the pH (that's why it's used in African cichlid tanks).


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## equatics (Apr 26, 2012)

It would be helpful if you could get a measurement of KH (Carbonate and Bicarbonate Hardness, "the buffer", especially of your tap water and the tank water as well. What I've read about pH adjusters is not to mess around with them. I think their buffer may give out unexpectedly.

If your KH is low enough, you might be able to tolerate and afford mixing distilled with tap, but even if successful at lowering the pH, KH will be low and not able to buffer much acid so you would get a dramatic drop in pH.

Nobody wants to hear this but people advise not to fight with the water, but accomodate your stock to what does well with your water parameters. You can look in the fish and plant listing for what tolerates pH 7.6 - I think maybe livebearers could be the place to start.

You can expect the pH to slowly drop over time as the tank "breathes" and ages


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## flight50 (Sep 30, 2008)

Nemo the Clownfish said:


> Nobody wants to hear this but people advise not to fight with the water, but accomodate your stock to what does well with your water parameters. You can look in the fish and plant listing for what tolerates pH 7.6 - I think maybe livebearers could be the place to start.
> 
> You can expect the pH to slowly drop over time as the tank "breathes" and ages


I hear this alot too as far as don't fight the water. True that it is easier to keep fish suited for tap vs making tap suitable for the fish. With this approach,your fish selection is limited. Fish are adaptable fortunately and can be acclimated to most water parameters within reason. The way I look at it, if there is a group of fish I want to keep, I will do everything I possibly can, to provide suitable parameters instead of settling for fish I don't really want to keep. For instance cardinal tetras and cichlids will require two totally different parameters. My tap suits cichlids better but that is not my intent to keep them.

I'd avoid using chemicals if at all possible. They are less stable and require alot of trial and error vs using natural elements. CO2 and R/O water are two options that can lower ph without chemicals. The only problem with distilled is the expense. Distilled water is pretty close to RO water if not the same. RO units can be a bit pricey but they will pay for themselves in due time. As far as the ratio, you will have to experiment to see what works for you. I use 60/40 to 70/30 with my tanks that house cardinals.


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