AheartlessFish

So i decided to take things to the next level of the hobby and test for how much co2 is in my tank.

I purchased an API KH/GH test kit. I read reviews on it and some people said they had trouble reading the results and such but also some who found that it was easy. I ended up buying one on amazon for like 6 bucks and put it to use. Little did i know, i should have listened to the guy who had trouble with it.

Product:
http://www.amazon.com/API-GH-KH-TEST...4517277&sr=8-1

Instruction says, add one drop, shake, repeat until testing water is YELLOW. *Note this is the only api test that DOES NOT come with a color chart. Usually theres a laminated color chart to compare the test tube right next to it.

So i filled up the test tube 5ml of fish tank water, shook up the bottle a little even though it didn't tell me to, added one drop in, capped the tube, shook it, and it turned LIGHT blue (i was expecting a darker blue), i added another drop and it turned LIGHT yellow. Is this when i should stop? In another container i had dropped in about 4-5 drops and it turned more of an ORANGE/YELLOW color than a bright yellow.

Anyone have any experience with this test kit? Does 2 drops indicate 2 degrees of Kh? My pH tested to be 6.4 and if im correctly using the co2 comparison chart, this means im doing everything right on my co2 levels (24 in green section).

http://www.gpodio.com/co2_chart.asp

I also have one of those Azoo indicators in my fish tank, i heard that if i dont use a specific type of liquid besides aquarium water then it wont work properly...If anyones curious its indicating Yellow (which means too much co2?)

Thank you for anyone's input in advance

XJfella95

That's how i test my CO2/KH as well. I count drops up to and including the one that turns it from blue to yellow.

Sometimes if I set it for a minute it'll turn back to blue so I consider that +1/2drop this gets me between the lines on the charts for better guestimating.

Seattle_Aquarist

Hi AheartlessFish,

Yes, it is a challenging test to read, especially if you have soft water like we do in Seattle. The color typically turns here between the 2nd and 3rd drop. The way I look at it is blue is blue, next comes green, and then yellow....I don't worry about the brightness.

As for you Azoo tester, now that you have a KH test kit you can mix up some 4.0 dKH water (distilled water + baking soda), fill your drop checker 1/2 full, add a few drops of indicator solution and then just monitor the color. Without 4.0 dKH water for your drop checker the reading is inaccurate.

AheartlessFish

okay if thats the case im gona stick with 2 dkh :P that is how u read it right? each drop = a degree of kh...

As for the 4.0 dkh water, how much baking soda do you put in? do you have a specific recipe for this? i am very interested in using it. Also does it have to be distilled?

Seattle_Aquarist

Hi AheartlessFish,

Here is the calculator I use for adjusting my dKH when necessary. According to the calculator adding .08 teaspoon (about 1/12th tsp) of Baking Soda to 1 gallon of distilled water will result in a 4.0 dKH solution. I always start with distilled because I believe it results in a more stable solution.

AheartlessFish

WOah! thats a tiny bit of baking soda for 1 gallon of water! :P sounds good ill give this a try

AheartlessFish

So i got my hands on baking soda...but not distilled water...

i used the tank water and added a pinch of baking soda to the water, shook it up, poured into the little chamber and added 3 drops...instantly the solution turned dark blue

Lets see how this plays out :O

AheartlessFish

Went out and got distilled water, added 1/12th tbsp of baking soda, shook it up, added to indicator, added 3 drops of the solution

1 hour later, the indicator shows darkgreenish. should i increase co2?

neilshieh

after adding baking soda to the water you should test it to make sure it reads 4dkh. and green means there's enough co2 except dark green means you're a bit on the low side. blue means not enough and yellow is too much. this is assuming the drops of solution you added is actually ph indicator which is bromythyl blue.
and you HAVE to use either RO water or distilled water because there's no impurities and is pure water.
you can get distilled water at any store like cvs, safeway, etc. they sell each gallon for about a buck each.
using tank water WILL NOT work because there are impurities and the ph is weird.
4dkh solution works because there is a relationship between hardness/ph/and co2. the relationship between co2 and ph is obvious but as to hardness and ph i'm not too clear myself.
hope you're successful! i had a bit of a tussle in creating 4dkh solution myself haha.
and i think api kh test kits are really easy to use. it's when the solution turns from blue to yellow you stop. nothing to it... even if it's a pale yellow as long as it's not blue. sometimes you'll get a green, but just add another drop.

Fishguy10

I have an API gh/kh test kit as well that I was having problems with, however I think that I found out what the problem was. When trying to determine my kh, I would add the very first drop of solution and the test tube would still look clear. I could keep adding more and more drops, but it stayed pretty much clear until it suddenly got very very dark orange/yellow. The problem was (at least I think) that my kh is >1. I knew that my kh would be low, but I wasn't exactly sure how low. If you have a water sample with a kh higher than 1 or 2 or so, it is fairly easy to notice the sudden change from blue to yellow.

When I mixed up a solution to put in my drop checker, (if you do not have a drop checker I would highly recommend that you get one, and it doesn't have to be an expensive fancy drop checker) I got some RO/distilled water and poured a few cups or so into a clean container. I then used a toothpick to add baking soda to the water. Add a little baking soda, test the kh of the water. If the kh is less than 4, add a little more baking soda with the toothpick, if it is higher than 4, add a little more water. Continue this process until you have water with a kh of about 4. It does not take very much baking soda at all.

When I tested my mixed water for the last time, the first drop turned it light blue, the second a more solid blue, the third a very solid blue, and the fourth turned it a dark yellow/light green. A fifth drop turned it very light yellow. Therefore, I determined that my kh is between 4 and 5 degrees.

With my kh being between 4 and 5 degrees, according to your CO2 chart, I should have between 30-37ppm of CO2 when my drop checker is green. (If I remember right, the indicator solution used in most drop checkers is blue at a ph of 7.2, green at 6.6, and yellow at 6.0) Therefore, my CO2 should be just at or slightly above "optimum" levels. Optimum levels seem to differ person to person, but it sounds like generally 30-35ppm is a good number to shoot for.

It takes a little bit of work to get distilled water with a kh of 4, but it helps give you a more accurate idea of how much CO2 you have in your tank. It's not a perfect test/indicator, but it is still fairly accurate. Sorry for the long reply, but I hope this helps.