Ph is low and keeps dropping

[kfries]

I am having trouble getting my pH to come up and stabilize. It have not been able to get it past 7.95 and it has been dropping down to as low as 7.75. 7.8-7.85 is the running average. I have an air line connected to my skimmer from outside the house. It is about 25 feet long. It is not near any of the furnace or water heater exhaust. It is in a very open area. I have been measuring parameters every 2 to 3 data and I am monitoring pH through apex. I recalibrate apex with the apex Cali ration solutions with very little change. My tanks is only about a month old. I moved live rock from my previous 20 gallon aio to this tank. It is a 150g system. I did lose one acro frag during the move but everything else is looking and behaving well. I do mix kalk in with my top off water which has worked well for me in smaller tanks.
Alk is 9.2-8.8
Calcium is 430-450
Mag 1350
Nitrate 5.5
Nitrite 0.2
Ammonia has zeroed out
The 20g tank I moved everything from ran around 8.0-8.2 pH. That tank used a small co2 scrubber. The large tank is on the other side of the room from the small one. I live in northeast Ohio so the weather is getting folded and the house is closed up. I did have the windows open a couple weeks ago and it had little impact. Overall the average pH is getting lower. Any advice would be helpful.

 

[exnisstech]

How does the tank look? I'm in Ohio also with 3 tanks running but I have no idea what my PH is in any of them.

 

[gbroadbridge]

I am having trouble getting my pH to come up and stabilize. It have not been able to get it past 7.95 and it has been dropping down to as low as 7.75. 7.8-7.85 is the running average. I have an air line connected to my skimmer from outside the house. It is about 25 feet long. It is not near any of the furnace or water heater exhaust. It is in a very open area. I have been measuring parameters every 2 to 3 data and I am monitoring pH through apex. I recalibrate apex with the apex Cali ration solutions with very little change. My tanks is only about a month old. I moved live rock from my previous 20 gallon aio to this tank. It is a 150g system. I did lose one acro frag during the move but everything else is looking and behaving well. I do mix kalk in with my top off water which has worked well for me in smaller tanks.
Alk is 9.2-8.8
Calcium is 430-450
Mag 1350
Nitrate 5.5
Nitrite 0.2
Ammonia has zeroed out
The 20g tank I moved everything from ran around 8.0-8.2 pH. That tank used a small co2 scrubber. The large tank is on the other side of the room from the small one. I live in northeast Ohio so the weather is getting folded and the house is closed up. I did have the windows open a couple weeks ago and it had little impact. Overall the average pH is getting lower. Any advice would be helpful.

Take a sample of tank water outside in a jar, aerate it with an airstone for 30 mins and then report back the measured pH

 

[salty joe]

Instead of mixing kalk with your topoff water, maybe try using only kalk for topoff.

 

[kfries]

Take a sample of tank water outside in a jar, aerate it with an airstone for 30 mins and then report back the measured pH

I ran this experiment this evening. The aerated sample increased by about 0.15-0.18.

Instead of mixing kalk with your topoff water, maybe try using only kalk for topoff.

I thought about running straight kalk, but ideally I would like to switch to all for reef instead of the kalk. The kalk is giving me some pH boost so I am hesitant to switch right now. I do mix it at the 3/4tsp per gallon. I am using BRS kalk.