lowering pH

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perrush
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Joined: 13 Mar 2003, 22:06
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lowering pH

Post by perrush »

Hi,

I was wondering how you guys lowered the pH below 7.

'normaal', 'pure' water which is completely aireated won't go below 7 (if you have at least some KH left) (with pure water I mean water with only the carbonate buffer present).

I know you can add a phosphate buffer or some other buffer, or some kind of tanins (wood, peat, ...).
The problem with the first is that you raise your PO4 levels way up, can't be a good thing.
The problem with tanins is that's more difficult to get the pH steady (many waterchanges, amount peat/oakextract to be dosed, ... influences the pH)

I just wanted to know how you do it.
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metallhd
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Post by metallhd »

nothing fancy, just DIY CO2 and Tetra Blackwater Extract in half the recommended dosage once a week . . . I guess regulated CO2 would be an alternative, but for it you would need good lighting and presumably live plants, unless you were introducing it just to lower the pH - keep in mind you will lose CO2 to surface agitation too

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perrush
Posts: 30
Joined: 13 Mar 2003, 22:06
Location 1: Belgium
Interests: tabletennis, Aquaria

Post by perrush »

metallhd,

I have a CO2 system in my planted tank. But this is not on option with L-ies because you need a strong current and will loose lost of CO2 to the surface.

And not sure what effects this blackwater extract has. It's surely an acid and will breakdown your KH (HCO3-) and replace it with tanins which influence your KH measurement. But again, I don't think this is the way to go in a breeding setup with lots of water changes
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Barbie
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Post by Barbie »

When you say "pure" water, are you talking about water that's been through an RO filter with a kH of less than 1?

In Anchorage, the pH was 7.8 out of the faucet, and the kH was 3 degrees. I would fill a 40 gallon barrel, circulated with a pump and heated, and add 1/4 teaspoon of acid buffer. This would push the pH down to 6.5 or so, and by the next day it would be back up to 7, so I'd add another 1/4 teaspoon, which would effectively drop it to 6 and keep it there. I used this water for weekly water changes for my discus and softwater fish, and they thrived in it, it stayed nicely stable, as long as I kept up with my water changes.

Fish themselves are going to be "softening" their water, as a byproduct of their waste, and also acidifying it, so if you're using pure RO, the pH is gradually going to start falling, and that will accelerate, even with the addition of more RO water, as it has no additional ability to hold it stable, whether it entered the tank at 7.0 or not. They sell numerous products to add buffers to your water, but I have had great luck just readding tap water to the RO water to get the kH up to 3 degrees or so.

Barbie
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