chemistry question

I thought a KH of 120-180 ppm was ideal. The higher concentrations, 300 - 200 ppm, also were 'off' the chart i use to measure co2, so I figured more is not better from that direction, too.

OK, so what /should/ the gh and kh be, then? Care to point me in a direction that has a document that has some information about what kh and gh have to do with plant health?

I don't see how water changes would ever raise my KH, since the tap water here registers as 0 ppm KH.
 
I'm a bit lost here. You want to lower your KH yet the tap water is at 0ppm.

esworp said:
OK, so what /should/ the gh and kh be, then? Care to point me in a direction that has a document that has some information about what kh and gh have to do with plant health?
Click to expand...
Truth is, if everyone who grows plants were to post their KH and GH values you would probably see just about every combination there is. Most people make the best of what they have and do fine.
 
whoops.. last message i posted, I wrote raise when I meant lower...

Sure, I could do heaps of water changes to bring the alkalinity down, but I figured I'd ask if there was something else i could put in the water to lower it instead. It would mean a more stable tank chemistry if i didn't have to drain, fill, dose etc..
 
Adding buffers, pH "adjusters" and such ilk does not help the water's stability at all. Just how would it work to ADD ions to the water to LOWER the concentration of ions in the water?

So, tell us, what is the KH of your tap water - 0, 300, 200?

If zero, you need to supplement.

If 200, ignore it. But you will need large scale water changes to keep up with that utilization rate.

If 300, just what is happening in the tank that uses up 180ppm of CaCO3 equivalent in 9 days? At that rate you need to be adding 20ppm equivalent per day just to stay even.
 
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If you are using CO2, your KH should be well above 3 degrees, 4-5 is safer.

You can add sodium bicarbonate, baking soda (commonly Arm& Hammer brand from the grocery store), but you should do the addition before adding the water to the tank. Sudden largish changes to the KH of the tank itself is dangerous - you can osmotically shock the fish. And you will need to monitor the tank KH routinely to keep it stable.
 
Where do you live where the KH is 0ppm???
Few places exist like this.

That's as good if not better than RO water.

KH really doesm not matter in terms of plant health if ample CO2 is present.
Having KH at about 30-300ppm is nice since you can measure the CO2 with the KH/pH. But if your KH is declining in the tank, something else is occuring, namely the plants are going after the KH(-HCO3) as a source for DIC carbon instead of CO2.

They do this when there is not enough CO2 in the water for a given light level.

GH is Ca and Mg, both plant nutrients, you need these.
Again, 50ppm or higher is good for GH.

I'd make certain about the KH reading out of your tap, something sounds fishy there.

Regards,
Tom Barr
 
could be old or incorrect test strips? I'll do a recheck, heeding your suprise at such a number.. I'd be surpised to find that the florida panhandle would have such fine drinking water during spring break, where you can smell the tourist poo for miles away from the treatment plants :p
 
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