# kh for ro water



## timwag2001 (Jul 3, 2009)

just curious if anyone does anything about kh in their ro water.
should i just bring it up a degree or do i not need it?


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## Darkblade48 (Jan 4, 2008)

If you are mixing the RO water with tap water, then would the reconstitution not bring the kH of the RO water back up?

I assume you are mixing the RO water with your tap water and not using it straight.


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## timwag2001 (Jul 3, 2009)

i just started using the ro water and have been using it straight


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## Hoppy (Dec 24, 2005)

You won't be successful with plants if you use RO water straignt. The plants need calcium, magnesium, Potassium, which will be absent from RO water. This is why they sell Equilibrium.


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## DaveK (Jul 10, 2010)

Hoppy said:


> ... This is why they sell Equilibrium.


IMO, you can use a product like that, but it gets expensive fast. A 4.8 K (about 10 1/2 pounds) costs about $55 to $75, or about 5.25 to 7.14 per pound. It's a lot more in the smaller containers.

A typical price for the bulk chemicals from an aquarium bulk supply place is only about $3 a pound, a much better deal, especially if you make large amounts of water. Remember some of those ADA systems use water changes of 50% a week. (although I admit that I'm too lazy to change that much water each time)


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## timwag2001 (Jul 3, 2009)

i use barrs gh booster, kh2po4, kno3 and csm+b.

what about kh though?


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## timwag2001 (Jul 3, 2009)

on top of the kh question.

does anyone have the numbers on how many ppm barrs gh booster brings the calcium, magnesium and potassium up? i know i've read it but i cant seem to find it right now


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## DaveK (Jul 10, 2010)

You use calcium chloride to boost KH

You don't really need to know how much gh booster you need to add. Just rest your water, for GH, then add a measured amount, wait a few hours and retest. Now you know how much you need to add to get to the test reading. Now you just do the math to figure out how much you need to add.


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## Imaginary1226 (Jul 27, 2010)

I use straight r/o water with my planted tanks, only thing I add is r/o right. I tried the kh thing for a while but it just wasn't worth the frustration. I can keep most plants alive pretty well.


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## timwag2001 (Jul 3, 2009)

DaveK said:


> You use calcium chloride to boost KH
> 
> You don't really need to know how much gh booster you need to add. Just rest your water, for GH, then add a measured amount, wait a few hours and retest. Now you know how much you need to add to get to the test reading. Now you just do the math to figure out how much you need to add.


 
or i could just use baking soda.

and yeah i could do that, but that is a hassle. what i want to know is that barrs gh booster raises calcium, magnesium and potassium to how many ppm. i dont want to know just what my gh is, i want to know how many ppm of calcium i have. do you have a potassium test kit?

just looking for numbers


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## Hoppy (Dec 24, 2005)

DaveK said:


> You use calcium chloride to boost KH
> 
> You don't really need to know how much gh booster you need to add. Just rest your water, for GH, then add a measured amount, wait a few hours and retest. Now you know how much you need to add to get to the test reading. Now you just do the math to figure out how much you need to add.


KH is the ppm of carbonate in the water. There is no carbonate in calcium chloride, so that *does not* increase the KH. If you have even 1 dKH of carbonate hardness you have enough. It is that first 1dKH that acts as a buffer against large changes in pH caused by changes in ppm of CO2 in the water. Further increases in KH just raise the pH. Many desirable plants do best at low KH.


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## deleted_user_7 (Jul 7, 2003)

How many tsp. of baking soda should you add per gallon of RO water to get 1 dKH?


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## timwag2001 (Jul 3, 2009)

ok. thanks hoppy. so i'll just raise it to one degree


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## wkndracer (Mar 14, 2009)

I use Arm & Hammer, not the store brand BS.
To increase KH
1/8 TSP : 6.5 gallons = 1dKH
1/4 TSP : 13 gallons = 1dKH
1/2 TSP (2.2grams): 26.4 gallons = 1dKH


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## houstonhobby (Dec 12, 2008)

I use calcium carbonate to boost Kh. I don't want chloride ions or sodium ions either one. Calcium carbonate is 3.00 per pound from aquariumferts.com and works great as a Kh booster. I also use CSM+B, ferrous gluconate, and Barr's GH booster, all of which come from the same source.


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