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Does tank size effect ph?

Ttran102

Well-Known Member
BRS Member
Reason I asked is because before when I have a 90g tank my ph is running 8.1 to 8.3 which is ideal but now i have a 220g tank in the same room but ph is running in the low side 7.8 to 7.9 and i barely can get it up to 8.1. Its in the basement in the same room and I don't know why this happen. I tried to open the window to see if it help but i barely move. Really don't want to add an co2 scrubber to chase number any recommendation?
 
Have you calibrated the pH probe recently?
 
is there any air exchange in the roomi
It's an open room and Noone goes down there beside me when I feed the fish or do some maintenance. But don't know why value is so much difference from before when I have smaller tank.
 
@dz6t i havent set up my calrx but with this ph value I'm afraid when I do it might drop even more. Never run kalkwaser before so don't know if I should do it this time to boost ph.
 
Keep in mind your old tank was probably much more full of coral/coralline algae. Coral and coralline algae both photosynthesize, so they are converting CO2 into O2, thereby increasing pH. All of those fish in the system are doing the opposite, using O2 and converting this to CO2. So in a new tank with little coral/coralline but large volume of fish, the respiration rate may be much greater than the rate of photosynthesis.

Odd that pH does not increase with an open window, leads me to believe there is not enough agitation. Is your skimmer going? Maybe try opening a window and also opening up the stand to allow fresh air into the cabinet?
 
Keep in mind your old tank was probably much more full of coral/coralline algae. Coral and coralline algae both photosynthesize, so they are converting CO2 into O2, thereby increasing pH. All of those fish in the system are doing the opposite, using O2 and converting this to CO2. So in a new tank with little coral/coralline but large volume of fish, the respiration rate may be much greater than the rate of photosynthesis.

Odd that pH does not increase with an open window, leads me to believe there is not enough agitation. Is your skimmer going? Maybe try opening a window and also opening up the stand to allow fresh air into the cabinet?
You think another pump near the waterline will have more agitation? And yes my skimmer has been running since day 1 and pull out a lot of nasty stuff because i have a bunch of tangs. and about the window i just crack it open a little since its winter time but enough to feel breeze coming in right where the tank is but don't know why it didn't help much. I will open the cabinet door see if it help at all but doubt will do anything. I really don't want to drill any hole to run an airline from outside to skimmer. Come to an end i might run kalkwasser down the road for this situation if i have to.
 
You think another pump near the waterline will have more agitation? And yes my skimmer has been running since day 1 and pull out a lot of nasty stuff because i have a bunch of tangs. and about the window i just crack it open a little since its winter time but enough to feel breeze coming in right where the tank is but don't know why it didn't help much. I will open the cabinet door see if it help at all but doubt will do anything. I really don't want to drill any hole to run an airline from outside to skimmer. Come to an end i might run kalkwasser down the road for this situation if i have to.
Maybe try moving another pump closer to the surface first? If it were me I would try to move the front left vortech as high as you can without creating a vortex
 
I think it may be the rocks that you are using in the new tank still curing. That will acidify the water and lower the pH. But the pH range is ok at 7.8.
 
When I first started reading this post my mind went to calibration as well. I don't think I would have done it though. I think I would have swapped the probes (if you're using 2). Having both tanks in same room as a sort of "controlled experiment" would have been interesting to see if your values stayed the same or the difference moved with the probes. Recalibrating creates a 3rd variable. Probes age and still function, but inaccurately in my experience. Now and then when I'm all perky and cleaning or swapping return pumps I also swap the probes. Look at your graphs the next day and see if there's a shift in values.

Be sure you have respect for the temperature of your calibration fluids. If they're at room temp and you stick the probe in the packet you will not get an accurate calibration. They must be at same temp of your tank!

Hope you get if figured out, the different ratios of fish and rock sound like the culprit though.
 
When I first started reading this post my mind went to calibration as well. I don't think I would have done it though. I think I would have swapped the probes (if you're using 2). Having both tanks in same room as a sort of "controlled experiment" would have been interesting to see if your values stayed the same or the difference moved with the probes. Recalibrating creates a 3rd variable. Probes age and still function, but inaccurately in my experience. Now and then when I'm all perky and cleaning or swapping return pumps I also swap the probes. Look at your graphs the next day and see if there's a shift in values.

Be sure you have respect for the temperature of your calibration fluids. If they're at room temp and you stick the probe in the packet you will not get an accurate calibration. They must be at same temp of your tank!

Hope you get if figured out, the different ratios of fish and rock sound like the culprit though.
Yes I did put the calibration liquid inside the sump to match temperature and the probes is brand new since I bought the apex brand new in box. I also have a brand new ph probes for the calrx I might switch it to see if that will make any difference.
 
How old is the 220? How many inches of sand do you have? How many fish do you have? If you have tangs How big are they? Reefers always over look these key things in their tanks that will add c02 to their tanks.
 
How old is the 220? How many inches of sand do you have? How many fish do you have? If you have tangs How big are they? Reefers always over look these key things in their tanks that will add c02 to their tanks.
it is fairly new started in October so about 2 months mark. It is bb tank and have 6 tangs and they all about 3-4" and 3 anthias about 2".
 
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