The Planted Tank Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
90 Posts
Discussion Starter · #1 ·
Yesterday my pH measured 6.5 right before my co2 came on.
By the time my CO2 was about to turn off, about 8 hours later, my pH was at 5.95 but my drop checker was straight yellow.

I've been trying to get near a 1 point pH drop on my tank and was wondering how accurate this is.

Is it a 1 point drop from before the lights come on? Or a one point drop on degassed tank water?

Is it safe to assume my degassed water would have a higher pH than 6.5, and I shouldn't drop my pH down to 5.5 in order to achieve the full 1 point drop?
Should I let my tank water sit out for 48 hours in order to get the base reading? Then drop a full point (or 1.2, 1.3) from there?

My KH is 2 or 3.. I'm due for another reading. I use 80-90% RO/DI to Tap.

Any help would be appreciated.

edit: just took a reading on some tank water that's been in a shot glass for 18+ hours. 7.15 pH
 

·
Registered
Joined
·
1,273 Posts
The 1 point drop is even more an aproximation than the pH/KH table. But, hope my values below give you a starting point

I am having a similar KH and my lowest pH is 5.8, with good plant growth and no fish distress. I went even lower but some shrimps were not that happy. Before CO2-on my water reads at 6.3. A degassed sample had the pH of 7.5. So for me it is a ~1.5 drop but at this point I have good light with very high plant density, your aquarium might have different requirements. If fauna is present always increase CO2 slowly, over days or weeks.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #3 ·
Thanks! Sounds like enough confirmation to me for now. This is at roughly 1bps in a 12 gallon long using a GLA atomic inline diffuser.

I'll give my tank water shot glass another 24 hours to degas and take a final reading. As long as it's within 1.4 or 1.5 pH points from 5.9 I'll leave as is.

I hit 5.8 yesterday when the BPS was higher and I don't think my puffers enjoyed it very much.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #5 ·
Go by fully degassed tank water, because CO2 from the previous day may or may not be completely gone when it's time for the lights to come on again.

Thanks burr, that's what I'll do. I don't know the laws of water too well, but it seems to be degassing much much faster in a shot glass than it is in my tank. I guess the volume plays a large role.
 

·
Registered
Joined
·
1,273 Posts
Yes surface area : water volume plays a role, especially if surface agitation is present.

Most things we have in the aquarium continue respiration during night. From aerobic bacteria to plants and fish, they all release CO2. If you have enough of those and limited surface agitation your pH will stabilise for the duration of the night, mine does so at 6.3

In the glass there are few such CO2 producers so it can degas.

Water is more complex than we make it to be... There is even a "Master of Water Science"

Sent from my HTC One using Tapatalk
 
1 - 6 of 6 Posts
Top