[Lousyweather]

A new tank, no animals or plants yet. Ecocomplete as substrate, 3 pieces of mopani wood. Tap water parameters are 6.7 pH, 4 dKH, 5 dGH, TDS 57.

I put the water in the tank. Wait a day. Water parameters are now 7.4 pH, 4 dKH, 5 dGH, TDS 126.

Now, obviously the substrate/wood raised my TDS and pH.

So, I put my GLA drop checker in use. The indicator was blue, reference green. I figured that made sense. The drop checker remained the same for 24 hours. So, I began my CO2 injection. I set my controller to start CO2 at a pH of 6.8, and turn off at 6.5 . Which it did. The drop checker turned green, a perfect match to the reference solution. All was good in the world. So, I decided to see what happened if I shut off my CO2. I shut it off this morning.
Now, 8 hours later, my pH is 7.4, but the drop checker STILL shows a nice green! I understand there is a lag, but have read it's a couple hours. Could the CO2 still be staying in solution since I have no plants to use it?
I have good circulation, 2 Eheim 2217, as well as 2 Koralia nano 240's.

 

[DaveK]

Sometimes the solution sold for the drop checker isn't very good and doesn't work right. I found I got much better results mixing my own drop checker solution.

You can do a quick test. Remove the drop checker from your tank and see what happens. It should turn blue fairly quickly. If not, the solution isn't working quite right.