Help with KH and CO2

[Haag13]

Me again with more questions. I've just setup a DIY jell-o CO2 system for my 29g tank and before I hook it in I was trying to get some baseline readings on my current CO2 levels so that I can check later to see if my set-up is actually doing anything or is worthwhile. I've read that most people check their CO2 by using a function of their KH and PH values so I just got an API test kit for KH. The kit says to count the drops it takes to change the color from blue to yellow and read the chart based on how many drops are needed. My question is what is their definition of yellow? In one part of the direction it says "change from blue to yellow," then it says the "number of drops to turn the water in the test tube bright yellow." What the F%$#? I add one drop and it's blueish, then 2 drops it's about clear, then 3 drops it's faintly yellow. This is compounded by the fact that with the PH test kit I can never be more accurate than 6.6 or 6.8 or some difference of .2. This may seem kind of petty but when trying to figure out my CO2 with a variation of PH of .2 and 2 or 3 degrees of KH, it means a big difference. My grandfather has a fishery in North Carolina and he has all kinds of fancy electrical metering devices and probes to read any information he could want but I don't feel like dropping a few grand to know this stuff. Can anyone offer me some help or let me know how they test their parameters? .....Or maybe just tell me to quit being so picky and chill out ?

 

[WyldFya]

The pH to KH relationship only shows what your potential is, but not what you actually do have. API tests in general are not that accurate, and should only be used to ball park.

 

[Haag13]

how do you measure your CO2 wyldfya?

 

[Haag13]

Howdy,

That's all great info above, but the "classic" way to read your CO2 levels is a simple table. All you need to know is your current pH value (best measured with a permanent submerged pH indicator in your tank) and the kH of your water. These two parameters are all you need. To my knowledge, every CO2 kit is sold (or at least should be) with a table for according readings. Check your package inserts or visit the website of a company selling CO2 kits.

HarleyK

From another thread and a few posts like this one I became a little confused I guess. I didn't understand how with just PH and KH you could assume the CO2 levels but I didn't really know. These two factors giving you an approximate potential for dissolved CO2 makes a little more sense though. Is a CO2 test kit, strips, or meter the only way to measure dissolved CO2?

 

[dodgefreak8]

drop checker

 

[WyldFya]

Take your base reading of ph and KH before your co2 comes on in the morning. Monitor it all day long. You will see it gradually drop down. Eventually it should bottom out, and either sit or your co2 will turn off. The final reading is actually the rating of co2 in your water. Taking an arbitrary reading in the middle of the day will tell you nothing, but a base line.