Ro Water Will Not Reduce Ph?

[dingweding]

I need to use RO water to mix my tap water, in order to make my water soft and acid.

to my surprise, although the water become much softer, the PH does not change much.

i test the PH of the RO water as well, it does not have much difference from my tank water.

why is that?

 

[natalie265]

Interesting. What is the ph of your RO water? I just tested mine and it is 6 or less (my test kit doesn't go any lower than 6).

 

[three-fingers]

RO water isnt meant to decrease the pH, and is really only meant to be slightly acidic.

Pure water should be pH 7.0 and decent RO water should read around that, but will be lower due to dissolved CO2.

If the RO was making the water acidic I would be concerned. Is there other chambers on the unit or is it just an RO membrane?

 

[dingweding]

it is a porper RO unit with all kinds filter. i test the ph of my RO water is around 7, but it is much softer than original tap water.

but i do want to reduce my ph a little as well, if RO water can not do that, how can i achieve it then?

 

[three-fingers]

First of all, why are you trying to lower the pH? Different methods have different plus points, and if you only want to lower it a little, it may not be worth the bother. After all, it's the hardness that is more important.

But adding things like bogwood, oak or even better Indian almond leaves to the tank would be great. In some cases adding peat to the filter is the best option. Or you could add blackwater extract to the tank and then every bucket of water you put in during a water change.

 

[Aphotic Phoenix]

If you have extremely hard tap water (like mine), even cutting your tap water in half may not cause much of a budge in the pH. I only went from ~8.2, to ~7.9 via cutting the tap in half. I only do so because I like delicate SA cichlids that do not appreciate my tap rating of 18 dGH (320 ppm), and it's TDS that are the issue, not the pH of the water.

 

[dingweding]

i need it for my CRS, i tried everything but they still keeping dying. so i have to accept everyone said to make soft and acid water. But London water is too hard, i tired peat, it work a little but made my moss looks so ugly. now the water is more soft, but i was surprised it is not acid as i expected. any suggestion?

 

[BigC]

I use a mixture of boiled rainwater and reverse osmosis water to breed soft water killifish.
The species I'm dealing with at present is Rivulus xiphidius. The tank water is TDS 15 (divide by 17.9 to get dKH) so it's below 1'dKH. The pH is around 6.5 which is still too high for breeding this species. I use Hydrochloric Acid for dropping the pH (4 droplets in 10 litres) It will drop the pH like a stone. (this is performed outside the tank at waterchanges and in no way should be added directly to the main aquarium)
This stuff is lethal and will burn a hole in just about anything including humans.
So try mixing rainwater with your RO in different permutations utilising a 10ltr bucket and a litre plastic measuring until you can get the mix almost right, then you can add Blackwater extracts, Peat, Indian Almond leaves or Alder Cones to condition it.

Regards
C