tap water KH is lower - should I add baking soda now? - The Planted Tank Forum
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post #1 of 45 (permalink) Old 02-12-2008, 04:35 AM Thread Starter
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tap water KH is lower - should I add baking soda now?

My tap water used to have (within the last month or so) a KH between 4 and 5. Now it's 3 - I hope. I never know about how much to trust these test kits. Should I add baking soda or is that not really necessary? My tank pH has gotten as low as 6 - perhaps lower. I don't know how much lower b/c the AP test kit stops at 6 (yellow). It's been yellow two nights in a row now. If anyone adds baking soda and doesn't have this calculator, I came across it. It seems good:

http://dataguru.org/misc/aquarium/Ca...&pHChange=0.12
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post #2 of 45 (permalink) Old 02-12-2008, 11:01 PM
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I would not add anything to buffer the kh. My kh is very low (not sure of exact value...have not tested for a while). I have a pinpoint monitor and with co2 injection my ph goes down to 5.2. I have no problem with fish or shrimp.

If you can not stand it and have the impulse to add some do it slowly. Do not just dump it in. Slow will give the critters some adjusting time.
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post #3 of 45 (permalink) Old 02-13-2008, 02:15 AM Thread Starter
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Originally Posted by riverrat View Post
I would not add anything to buffer the kh. My kh is very low (not sure of exact value...have not tested for a while). I have a pinpoint monitor and with co2 injection my ph goes down to 5.2. I have no problem with fish or shrimp.

If you can not stand it and have the impulse to add some do it slowly. Do not just dump it in. Slow will give the critters some adjusting time.
Thanks. Actually, I don't want to have to mess with it. I was just concerned b/c I've read that you must have a kH at at least three or above to use pressurized Co2 or you can have dangerous pH crashes.
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post #4 of 45 (permalink) Old 02-13-2008, 05:05 AM
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If you do get worried and want to buffer your kh a handful of crushed coral to your filter will do marvels.
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post #5 of 45 (permalink) Old 02-13-2008, 05:24 AM
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Crush coral will also add calcium increasing the GH.

There's no need to boost the KH, that 3 degree "limit" is old school myth. If you do want to increase it a little bit, then no more than 1 degree at the water change. Adjustments like those need to be done carefully as has already been mentioned, and in this case I'd recommend against it entirely.
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post #6 of 45 (permalink) Old 02-14-2008, 08:39 AM
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Originally Posted by indiboi View Post
Crush coral will also add calcium increasing the GH.

There's no need to boost the KH, that 3 degree "limit" is old school myth.
Excuse me but I partially disagree. 3 degree in not a myth a low Kh is sometimes unable to buffer pH changes and You can have a peak thath can be armful for fishes.

(Forgive me for my English, it's not my mother-tongue)
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post #7 of 45 (permalink) Old 02-14-2008, 07:57 PM
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Who is still passing this myth along? 3* (or it used to be 4*) with pressurized co2 is not neccesary. There are many who have injected co2 with KH that is less than 2* or even does not read 1* on a test kit and do not have any problems. There may be a rare expection (perhaps like using RO water, etc) but normally it isnt to important.
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post #8 of 45 (permalink) Old 02-14-2008, 09:58 PM
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KH is not a myth. Low KH will give you huge pH swings when using CO2....try it if you are not sure.

I second the crushed coral in the filter. I do about 1/3 cup for a 90 gallon and it completely disappears in about 3 months. I do 50% water change per week.
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post #9 of 45 (permalink) Old 02-15-2008, 06:52 AM
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Originally Posted by putty View Post
KH is not a myth. Low KH will give you huge pH swings when using CO2....try it if you are not sure.
That's what I mean. The problem is not with injected CO2 with a costant pH monitoring but in tanks with a lot of plants where CO2 is not constant regulated.
In this circustances if pH is not adequate you may have swings of some degrees in PH.

Everyone can verify it testing pH at morning and evening in the same tank...

(Forgive me for my English, it's not my mother-tongue)
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post #10 of 45 (permalink) Old 02-15-2008, 07:53 AM
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Quote:
Originally Posted by putty
KH is not a myth. Low KH will give you huge pH swings when using CO2....try it if you are not sure.
Quote:
Originally Posted by rudigiacomini
That's what I mean. The problem is not with injected CO2 with a costant pH monitoring but in tanks with a lot of plants where CO2 is not constant regulated.
In this circustances if pH is not adequate you may have swings of some degrees in PH.

You guys are really blowing this KH thing out of proportion if I were a newb and reading this I would be scared into adding like 10KH to my water KH is not needed unless you are planning on keeping certain fish that prefers alkaline waters.

I use only straight RO/DI water to which I reconstitute GH only to either 3GH~4GH. I do not add any buffer of any sort to increase KH so I do have the scary 0KH but this does not deter me from injecting lots of Co2, more than the accepted norm and I do turn off Co2 at nights as well. To give you an idea of how much I inject my DC gets green after 2hrs of lights on. Check to see how long it takes for yours to get green to get an idea of my injection amounts. Why? Just to show how rapidly I pulldown PH....again another scary topic for some.

As you can already guess my PH is naturally very low but none of my fish, 50+Amanos, 15CRS's, 10RCS's and plants has ever died or has had an issue with this huge scary Co2 swing that I hear so much about. I've been doing this for almost a year now.

Loachlady leave your KH as is.... it's perfect.


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post #11 of 45 (permalink) Old 02-15-2008, 08:44 AM
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Originally Posted by mrkookm View Post
You guys are really blowing this KH thing out of proportion if I were a newb and reading this I would be scared into adding like 10KH to my water KH is not needed unless you are planning on keeping certain fish that prefers alkaline waters.

I use only straight RO/DI water to which I reconstitute GH only to either 3GH~4GH. I do not add any buffer of any sort to increase KH so I do have the scary 0KH but this does not deter me from injecting lots of Co2, more than the accepted norm and I do turn off Co2 at nights as well. To give you an idea of how much I inject my DC gets green after 2hrs of lights on. Check to see how long it takes for yours to get green to get an idea of my injection amounts. Why? Just to show how rapidly I pulldown PH....again another scary topic for some.

As you can already guess my PH is naturally very low but none of my fish, 50+Amanos, 15CRS's, 10RCS's and plants has ever died or has had an issue with this huge scary Co2 swing that I hear so much about. I've been doing this for almost a year now.

Loachlady leave your KH as is.... it's perfect.
Maybe my Englih is so poor that someone misunderstand me but I don't want scare anyone
I want to share my infos and to learn from Yours.
I think it's correct to inform newbies correctly

So.
If You turn off CO2 at night You partially solve the problem.
If You have an electrovalve connected to a pH meter You solve the problem.
If You talk about pH Kh and CO2 you have to know and to say that they are mathematically connected and that plants fotosintesis influence CO2 (without Your control) so a low kH buffer can (not must) be a problem.

The response of DC (I think it's for Drop Checker) is correct in 2 hours. DC are slow to react to changes....

So at the end everithing depend on...
- on how many plants
- on how much CO2
- on kH starting point
- on many other things...
not in mythology

(Forgive me for my English, it's not my mother-tongue)
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post #12 of 45 (permalink) Old 02-15-2008, 10:28 AM
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So.
Quote:
If You turn off CO2 at night You partially solve the problem.
If You have an electrovalve connected to a pH meter You solve the problem.
I did run co2 24hrs for 7months before I changed to Co2 off at nights and never had any issues whatsoever.


Quote:
The response of DC (I think it's for Drop Checker) is correct in 2 hours. DC are slow to react to changes....
This needed elaboration as the mounting height/position of the DC, amount of KH solution as well as droplets of Bromothymol Blue affects the response time but thats another topic itself.

However, though the DC takes 2 hrs to indicate green my tank's injection method quickly gets levels to 30ppm+ very easily and much sooner than indicated by the DC. I do not use a PH controller to shut Co2 on/off so once my Co2 turns on it runs for 10hrs straight. If their was going to be drastic changes it would definitely happen during the timeframe and believe me you understood my injection method efficacy then you will understand better my point here.

These pictures were taken with a freshly prepared DC, anyone familiar with DC's know that changes during this break in period time takes much longer than 2hrs to show green, yet mine still changed within 2 hrs :


Quote:
So at the end everithing depend on...
- on how many plants
- on how much CO2
- on kH starting point
- on many other things...
not in mythology
I understand the point you are bringing to the table but try to see my point as well, this is based off real world experience and the reason why I suggested to Loachlady no change. In the end it depends on the user's goals, preference or educated guess.

BTW you're English writing is very good.. awesome di posti di lavoro


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post #13 of 45 (permalink) Old 02-15-2008, 01:05 PM
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Quote:
Originally Posted by mrkookm View Post
I understand the point you are bringing to the table but try to see my point as well, this is based off real world experience and the reason why I suggested to Loachlady no change. In the end it depends on the user's goals, preference or educated guess.
OK! You was right in what you suggested.

And you are right in your point of view
.
What was not right for me is when you consider the low kH a myth. For me myth is a strong word that matches with "urban leggend"... the relationship between Kh PH and CO2 is math.
What we are not able to consider in a tank is the amount o variables.
There are differences between 1 plant and 100 plants in same tank and in the same way there are differences betweena 100l and a 10l tank.
Without these parameters you can't say if 3dKh is a sufficient buffer for pH still if you know the amount of CO2 at that time.


Thanks for your apreciation on my english .

(Forgive me for my English, it's not my mother-tongue)
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post #14 of 45 (permalink) Old 02-15-2008, 02:38 PM
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I don't see how the variables you are mentioning have anything to do with me having 0KH. It really does't get any worse than what I have at any level because technically as soon as any Co2 hits my water there should be no swing but rather a crash based on the old school thought.

Look at the KH/PH chart and try to figure out how much Co2 is in my water at 0KH? However you can clearly see based on the DC that I do have Co2 in my water an lots of it too but why have I not crashed yet at any Co2 rate?

If I'm doing fine at 0KH with high co2 rates with a correctly config'd Mazzei injection where a 10Lb tank lasts me only 2months in a 90gal, I pretty sure Loachlady at 3KH will have no PH swing catastrophe. Overdose related deaths if Co2 is pushed to the limits...sure but not because of her KH is 3.


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post #15 of 45 (permalink) Old 02-15-2008, 03:03 PM
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The myth is not the KH will buffer the water and cause less a pH swing, that is science. The myth is how this is somehow super important and we need to keep a certain amount with co2 injection to avoid some major crash. A high KH will not significantly change the pH swing due to CO2. Injecting co2 will alter pH. It has to. Controller, solenoid, whatever, it doesnt really matter. I get a huge swing between night and day and this is fine. I set my controller so it maintains around 30ppm during the day and my tank fully degasses CO2 overnight, about a 1-point pH shift every day (I suspect this is much more than most, since I have a lot of gas exchange with overflows), and I have a KH around 2*. I would see 0 difference in night-day swing by doubling or tripling my KH, as it will be much smaller than what our tests can measure, like hundredths or thousandths(?) of a pH point less.

Lets look at an example. We will have to assume this is a perfect tank with no other acids/bases, and use chucks calculator at http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm. KH=1, pH=7.0 with no CO2 addition (3ppm ambient). Then we add CO2 until it reaches 30ppm. According to the calc, then our pH will be at 6.0, a 1-point drop. Now lets go to the other extreme, our KH=10 and our pH=8.0 with no added CO2 (3ppm). Now we bring the CO2 = 30ppm and according to the calculator we will have a pH=7.0, still a 1-point drop. I fail to see how KH has buffered the pH swing due to CO2.

Now perhaps it is different if your dumping in stronger acids in your tank? IDK. Other than in an instance were KH is being consumed in your tank, like I said earlier, or in hard water fish, or while using RO water, I see no reason to mess with KH if you have at least .5* . IMHO having to worry about one less thing in your tank, priceless.

I dont know the history behind the myth. I've only been into CO2 injection for about 3 years. But I figure it went something like this. Joe sets up a pressurized CO2 tank. After running it for a few hours he check his tank. he screams holly moley my tank is crashing my pH has droped a whole point! He dumps in enough baking soda or whatever so his pH goes back to near where it was before. He wipes the sweat of his forehead and feels confident now his pH is back were it was. But this is simply due to not understanding that CO2 drops pH with no effect to fish. I suspect those that dont have a large pH swing attribute it to higher KH but this simply is not the case. More likely they have a low amount of water turbulence (slower gas exchange) and dont gass off much CO2 overnight.
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