CO2 indicator questions

Hi,

I'm new to the forum, looked for answers for my question and found some interesting details but not exactly what I am looking for.

I am new to the aquarium hobby, and have a 30 l tank, about 22 l of water after substrate and rocks. I am interested in going to a bigger tank with plants in time, so using this tank as my learning tank.

I bought the Ista CO2 16g disposable defuser kit a while back. So you know, I don't have any plants that NEED CO2, but as I said as a learning tank I want get to as much right as I can before going bigger. Mostly have amazon sword and java moss, with 1 or 2 other water column feeding plants. Ludwigia Red leaf stuff. So again I know the plants don't need the CO2.

But here is my question, when I first got the kit and used it, the Ista all angle view CO2 indicator I have went from blue to green in about a day after 1 or 2 doses of CO2. Then I had some ich/ick (which ever it is) issues and had to focus on that so I left the CO2 alone for a bit. Now the ich/ick problem has been sorted for a few weeks now, and I started getting back to my normal routine.

However, for over a week now the CO2 indicator will not change colour, it stays blue, even with dosing once a day, I even dosed CO2 twice in one day to test, but nothing. And I know the test takes 2 - 3 hours to reflect. I replaced the fluid, and even got a JBL CO2 indicator in case it was an issue with the first one. But both now stay blue. I know the indicators actually measure PH and not CO2 directly. But I can't figure out why it worked before and not now? I slowed down my Aqauclear 20 HOB flow to the lowest it can go, as I read water disturbance can cause CO2 injection issues.

I use tap water with Seachem prime, and add Seachem Flourish twice a week. Both the tap water and aquarium water have these water parameters: PH = 7.4, GH = 5 dGH, KH = 4 dKH, TDS = 150 - 160. I have tested the tank water every 2nd days and the values don't move.

So my question is if anyone knows why the indicators worked in the past but now won't? Is it possible the plants are using the CO2 faster than I can inject CO2?

As for the tank, all looks happy and healthy, no fish are gasping for air, I have an O2 test which says my O2 is 4mg/l, and according to the instructions for the test, that is good amount of O2.

So yea, any ideas would be appreciated

 

Hi Ross, welcome to TASA.

How has your temps changed from when it worked till now.

Consider that you are measuring pH and not CO2 ... what chemical / substrate changes might have messed with your pH initially till now.

In the past I have found that our source water plays a big part in getting some sort of indicator working - but in truth it is just not worth the stress ... so start looking for bio-indicators of CO2 levels and be aware CO2 kills more fish than any other additive ( well that is the sentiment).

See this article on CO2 - it should help you in doing a checklist for things that might have changed.

https://www.co2art.eu/blogs/blog/13591641-7-things-you-need-to-know-about-drop-checkers

Later Ferdie