Kh and GH

[BKT]

Whats a good KH amount and GH? I'm transitioning the tap water to RO and want to make sure its correct.

[GaryP]

Are you referring to the hardness of the water coming from your RO unit?

If so, the answer is 0. A hardness meter just measures GH so KH isn't really a consideration.

[BKT]

I changed approx. 10 gal of water (5 gal RO water) just now and took a reading...the KH was 11 drops or 196.9 ppm. Now with this in mind and the transition taking place as I exchange tap water for RO water is this ok gary?

[BKT]

Or any one else that can answer this if you like...So I don't need to test the KH in my tank? I'm not sure I have a GH test kit...

[GaryP]

OK, gotcha now. There is a hodge podge of units used for measuring hardness (alkalinity). I guess you are talking about the hardness of the water you are using for make up water.

The units used are interchangeable. They are:

1 meq (millequivalent) = 2.8 DKH = 50 ppm.

If you are getting 197 ppm, it equals 4 meq and 11 DKH. That's perfectly fine for alkalinity, slightly above the average value for seawater (8.5 DKH).

You may be getting some alkalinity from tap water, but probably not a huge amount compared to salt water. You'll just have to make up the difference with a buffer supplement. I recall off the top of my head that Edwards aquifer calcium level is about 175 ppm, but don't remember what the alkalinity value is.

[GaryP]

OK, I stand corrected, the average value for alkalinity, as reported by SAWS is 253 ppm. That's equal to 14 DKH.

The average for calcium is 79 ppm.

[BKT]

gary, I need some advice real fast...if there is a number you can email with or I can give you my number, I want to make sure tonight that the ph won't crash. The temp is 79 and the ph is probably around 8.2 or 8.4...I saw my yellow tang rubbing his body against rocks...he's about 3 days old but I just want to make sure...my email is bturner35@austin.rr.com

if I'm able to call or you call me let me know..just covering my bases

[BKT]

So, call me slow, but is the water chemistry off, the KH I told you about, or should I do anything special?

[GaryP]

PM sent

[BKT]

thanks for taking time out to listen and answer questions Gary, we talked about alot so if I forget something and you realize you mentioned it to me before, thats why....I'M SLOW ...lol...my wife says I am...lol

seriously thanks man

-Brian

[GaryP]

NP, that's why we are here.