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New to RO dosing question

jivemonkey

New Member
Joined
16 Feb 2022
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22
Location
worthing
just set up ro for my planted tropical tank, the ro reads about 6 ph and after adding re mineral tropic it rises to a out 6.2 ish so told by LFS to add more as it will raise pH but not KH GH or alkalinity beyond a set point. After views on this approach please
 

GreggZ

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4 Mar 2022
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301
Location
Novi, MI 48374
Is the 6 pH reading right out of the RO or after it has come to equilibrium with the atmosphere? Just saying pure RO can change a bit after sitting out for awhile.

I don't know what is in re mineral tropic but if it raises pH then it is also likely adding carbonates and raising dKH as well.

The question you need to answer is if you WANT to raise your dKH and pH? Many planted tanks run at virtually zero dKH (pure RO). Plants love it and most livestock does great (but does depend on the specific livestock).

You will want to raise dGH a bit (Calcium and Magnesium).
 

RLee2

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Joined
6 Sep 2022
Messages
24
Location
california
just set up ro for my planted tropical tank, the ro reads about 6 ph and after adding re mineral tropic it rises to a out 6.2 ish so told by LFS to add more as it will raise pH but not KH GH or alkalinity beyond a set point. After views on this approach please
If you are using this
Screenshot 2022-09-12 at 12-06-16 Tropic Marin Re-Mineral Tropic.png

then the directions say
"Use of Tropic Marin Re-Mineral Tropic:
Add one level measuring spoon full for 4 US gal./15 l of water. Ensure that you use the enclosed spoon to measure a precise amount of Tropic Marin Re-Mineral Tropic. Use the spatula provided to wipe over the spoon and level the powder. Sprinkle one measuring spoonful onto the surface of the reverse osmosis water while stirring the water. Wait for each spoonful to dissolve before adding more Tropic Marin Re-Mineral Tropic. Yields a total hardness of about 7° dGH and a carbonate hardness of about 4° dKH, depending on the water. 7 oz./200 g of Tropic Marin Re-Mineral Tropic are sufficient for the preparation of approximately 200 US gal./750 l of reverse osmosis water
."
PH has a direct relationship to KH so the more KH the higher the PH. GH does not effect PH. I would just follow the directions on the label and that will reconstitute your RO water to a 4 KH and 7GH. If you have a small digital scale you can use weight to determine how much to use. It say 200 g treats 200 gal so 1 g per 1 gal so 10 g for 10 gal and so on.
As to the ph most water even RO water has co2 in it which will alter the ph. If you want an accurate starting PH of your RO water then let the water sit for 48 hours to off gas the extra co2. Then take your PH reading.
 
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dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
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14,580
Location
nr Bath
Hi all,
If you want an accurate starting PH of your RO water then let the water sit for 48 hours to off gas the extra co2. Then take your PH reading.
I think the <"whole area of pH and buffering"> is really problematic <"and conceptually difficult">, but the take home message is that you can't get an accurate pH reading for RO water, because the <"pH is never stable, and it doesn't matter">.

<"Theoretically RO / DI water should be pH 7">, but in practice it is lower due to dissolved atmospheric CO2, but, because pH is both a ratio and a log10 scale, it is <"pretty much meaningless"> in any water with very few dissolved ions.

cheers Darrel
 
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