KH and pH questions

[TheKillHaa]

hello all. Im not sure, chemistry is what only failed at school

first;
what is the max KH value permissible in a planted tank to let CO2 being dissolved by water?

second: if i add co2 to my tank but my pH doesn't change at all, am i dissolving any CO2?
thanks in advance.

 

[trong]

i'm not sure what the max value is, but i've tried many things and i like 6 or less. my fish like less.
how are you adding co2,,, cause co2 usually (always) lowers ph... how are you testing? how are you adding?

 

[TheKillHaa]

i'm not sure what the max value is, but i've tried many things and i like 6 or less. my fish like less.
how are you adding co2,,, cause co2 usually (always) lowers ph... how are you testing? how are you adding?

Thanks!, actually is not any issues, is just doubts i have not clear. i use very hard tap water, but i have Osmosis as well, so i can combine and achieve the desired Kh.

The co2 question is regarding somebody askme that he was adding co2 (i dont know how dissolve it) and his plants was bubbling but pH remains the same value. he dont know his KH. (i know bubbling could be due several factors, not only co2, but my doubt remains)

about me, i usually have from 5 to 16 Kh (GH from 15 to 30) and pH from 8.8 to 6.2 on several tanks, (i have almost 15tanks around and inside home). so i use many variables without found limits.
sorry about my english.

Regards.

 

[Philosophos]

I've been waiting for Tom to pipe up on this issue again. He was saying back in some old posts that KH doesn't matter much for plants.

For me, I find I like a KH sitting 6 or under as a matter of the fish I keep. It's the same reason i don't mind WC's every week or two on these tanks.

IMO ADA aquasoil is one of the best investments for a tank. It scapes decently, pounds in the nutrients, and drops the pH out for about a year. The CEC is as good as any other commercial substrate as well, so you always have a nutrient laden substrate.

 

[TheKillHaa]

thanks phil
once i asked about to stop usin RO for my plants and shift to very hard tap water. Tom replied me something like "dont care about GH, but KH.
i assumed that was because co2 incorporation. And it was, is harder as all know that high KH makes difficult the dissolving rates.

 

[Tom Barr]

No, it's(KH) not to do with CO2....more for some species of plants and for some fish.
This is a somewhat limited group, most do not care if the tap is hard KH's.

RO water is a PITA unless it is a few small aquariums.
Or it's built into your house, large tank for it etc.......hard plumbed etc.

It should dissolve just fine at higher KH's.
You can check the pH/KH/CO2 tables and see.

It should take the same CO2 amount/rate to dissolve 30ppm into a KH of say 2.5 and 10.
http://www.aquarticles.com/articles/plants/Podio_CO2_KH_PH_Chart.html
The pH is different(6.4 for a KH of 2.5 and 7.0 for a KH of 10), but the total amount of CO2 is still the same in both cases.

What types of plants/fish do you have?
Most can get away with the tap KH you have(is it about 8-10KH?)

Regards,
tom Barr

 

[TheKillHaa]

No, it's(KH) not to do with CO2....more for some species of plants and for some fish.
This is a somewhat limited group, most do not care if the tap is hard KH's.

RO water is a PITA unless it is a few small aquariums.
Or it's built into your house, large tank for it etc.......hard plumbed etc.

It should dissolve just fine at higher KH's.
You can check the pH/KH/CO2 tables and see.

It should take the same CO2 amount/rate to dissolve 30ppm into a KH of say 2.5 and 10.
http://www.aquarticles.com/articles/plants/Podio_CO2_KH_PH_Chart.html
The pH is different(6.4 for a KH of 2.5 and 7.0 for a KH of 10), but the total amount of CO2 is still the same in both cases.

What types of plants/fish do you have?
Most can get away with the tap KH you have(is it about 8-10KH?)

Regards,
tom Barr

U will be surprised of my kh in tanks around house.
i'll update data and post them later, im on office work right now

questions answered,
thanks!

 

[TheKillHaa]

no any surprise, i used to have awkard values before, but no this time ( i never test almost nothing, just no3 few times per month)


first, a short video of my outdoors tanks with Index Estimative dose:
[video=youtube;K6qCqGBV5gA]http://www.youtube.com/watch?v=K6qCqGBV5gA[/video]

there is two sets, left is line #1, (165 gal total) only glass acuariums, two years old, but some tanks are re-set every 6 months.
Line #2 is 4 months old, plastic totes, over 800 gal total (only showing one side in video). Each are interconected, but lines dont share their waters, recirculates among themselves.

Line 1, (average) (co2 was off 1 hour earlier of testing)
Kh 12, pH 7.3, mV 175

Line 2 (average)
Kh 18, Ph 7.13, mV 200

the "not as easy plants" i have them indoors.

ok.
a question:
the co2 charts are well know of its inaccurate on fish/planted tanks, because hardware or phosphates,, but, how its is affected? i mean, if chart gives me 25 ppm Co2 theorically, and i have heavy phosfates, (as usually) how much is affected the co2 value? increase or decrease co2 ppms?

regards.

 

[Tom Barr]

In virtually all cases, the errors are towards the higher ranges, giving people extra.........but "false" CO2 ppm's.
So they think they have more CO2, than they do.

It's also dependent on where the measurement for CO2 is taken and the time it takes to obtain it.

Regards,
Tom Barr

 

[TheKillHaa]

ur right, i've seen many times that drop checkers and Kh are giving me a awkard readigns of Co2, (like high ppms) while plants are giving some signs that they dont really have enough or fishes confirm others.

temp is also important on these setups, as high temp release co2 easier and quicker from water.

what about phosfates? do you know how they really affect the readings on co2 charts?

regards.

 

[hani]

This is interesting, bc i am having some issue with my tank, my kh 2, gh 5-6,ph 6.7 with co2 off, i had early signs of BBA, after about 3 months, so crank the co2 up, watching the DC turning yellow(with kh4 in it) at PH 6.1, decided to keep going, i hit a ph 5.3, fish started to gasp , down to 5.45 no issue, (the prop calibrated then replaced cause i thought something wrong with it, no change). now plants pearlling.
the whole issue started after i increased my po4 from 0.2-3 to 1.

 

[TheKillHaa]

the whole issue started after i increased my po4 from 0.2-3 to 1.

i guess the whole issue started because you tank was not prepare to rise PO4. (first fix co2, second rise po4)

i been having PO4 +5 ppm on these tanks for weeks with no issues.

regards.

 

[hani]

what am trying to say is, the DC was miss leading at low kh, now i have the co2 adjusted at ph 5.4, and its hitting 6.7 in the morning, this is not my first tank, i found that wide ph range is unusual and wounder if po4 playing any role.

 

[TheKillHaa]

got it, i read it twice now... sorry by my confusion.

i see what you mean, in this case, the deduction could be that on higher values of Po4 DC start turning yellow without having enough Co2, huh?

 

[Tug]

It would be nice to find a fuller explanation of KH and buffering capacity. One that finally turns the light bulb on. How it works, what it effects, and what ever it's mg/L, CO2 concentrations are not changed - the pH is just more stable. The problem would seam to be more about discerning the color at any one time and the accuracy of the drop checker solution. While I would like to know more about it, how PO4 effects pH, I think the question has little to do with the concentration of CO2 in the DC. http://www.barrreport.com/showthrea...wo-are-better.-(or-wet-killed-a-bunch-of-fish.)

 

[Biollante]

Got Holes?

Hi,

PO4 tends to reduce pH since it forms a weak acid.

The law that is the basis for drop checker operation is simply that the air in the drop checker will take on the same amount of CO2 as the water and dissolve into the water of a known alkalinity in the vessel of the drop checker. Indeed the trick is “reading” the color of the water. :gw I think it helps to use three or four times the standard amount of Bromothymol blue to intensify the color.

As to the rest, buffering is a complicated subject.

The Killhaa’s situation is similar to my situation with dozens of tanks and tubs on a single line and I may have more to say about that later. Can you say glass hole saws and bulkheads?
http://www.glass-holes.com/category.sc?categoryId=7
http://www.drillglass.com/glassdrill2.html?gclid=CI7Kke_8y6ECFSP6agodGAYIcQ

Biollante

 

[Tom Barr]

It would be nice to find a fuller explanation of KH and buffering capacity. One that finally turns the light bulb on. How it works, what it effects, and what ever it's mg/L, CO2 concentrations are not changed - the pH is just more stable. The problem would seam to be more about discerning the color at any one time and the accuracy of the drop checker solution. While I would like to know more about it, how PO4 effects pH, I think the question has little to do with the concentration of CO2 in the DC. http://www.barrreport.com/showthrea...wo-are-better.-(or-wet-killed-a-bunch-of-fish.)

I do not think many hobbyist really know or have good methods to measure such differences.
At least not yet or anytime that soon..........

Reseachers perhaps...........but not hobbyists.
And they are the ones that need it and then need to measure CO2 critically.


Regards,
Tom Barr