i was wondering if something was wrong. i have a pressurized co2 system and i keep the ph at 7. if you let my tap sit for 24hr the ph is 8. the tank is on a timer. goes off 1hr before the lights go off and comes on 1hr before the lights come on. but at night or morning the ph is the same never moves. i'm using a red sea co2 indicator and it stays green 24hrs a day. saying i always have the same amount of co2 in my tank at all times. how can i have the same amount of co2 all day and night if the co2 not running. and the fish are fine no gasping and i theres really no top water movement or air stones

Well, if you have very little movement of the water surface less CO2 will diffuse out at night. You may not be loosing enough gas to drop the CO2 levels noticeably.

If you are using aquarium water instead of a standard solution in your drop checker it could have buffers in it keeping a constant pH.

Keep in mind that the color of CO2 checker really tells you the pH of the solution in the checker, not the level of CO2 directly. We know the CO2 level by knowing the KH and pH of that solution. At 4 degree KH and 6.6 pH will give you a green color with a bromo blue indicator. These values also correspond to a 30 ppm CO2 concentration which is why they're typically chosen.

ok thanks....

The response time for the CO2 checker can be rather slow.

Older tanks often will have fairly stable pH's, if so, then you might consider deep vacuuming the substrate in 1/4 sections each week to clean it out good and then replant.

The accuracy of the color in the drop checker is only so so, but even with a pH monitor/probe, I've seen this happen.

Not quite sure, but it does tend to bother me some and I will clean out the tank good if so and do a large water change.
That seems to solve the issue.

Also, when plants are growing well and taking things in via the roots, they add acids to the substrate, they do this to make nutrients there more mobile to remove them for uptake. This can have an effect as well. Hard to show that in situ though.


Regards,
Tom Barr

its a new tank . and i do 50% water changes every week. and i even re tested my ph monitor/probe. plants are growing really well

Do you have good flow etc?
Seems weird.

Older tanks perhaps, not newer ones.
If plants are fine, keep doing what you are doing, are there any algae?
Plant issues?

Regards,
Tom Barr

i had some brush algae that came with my SAG. but it's gone now. other than that no..

no i really don't have much of any flow. not at least on top