Can anything other than co2 cause low ph

[Herby’s reef]

My ph dips to 7.75 at night and i truely believe it is causing my corals issues. I don’t think it is due to excess co2. My room air co2 monitor only shows co2 in the 500 to 600 range. I have an outside air exchanger with the output just over the tank. I have outside air going to a co2 scrubber going to my skimmer. I dose 11 liters per day of saturated kalk on a 180 gallon system. How is my ph still low? Oh, and I have two ph probes that I have calibrated multiple times and they show to be accurate in reference solution. I am going crazy trying to figure this out!! It has not always been this low, but I have always struggled with this, hence the air exchanger and all the stuff.

 

[blaxsun]

First, what are you using to test your pH? Second, what does the pH peak at during the day?

 

[mdb_talon]

Co2 and alkalinity.

As usual the easy way to confirm co2 is an issue is an outdoor aeration test. Assuming ph is then what expected for your given alk then you either need better gas exchange in tank and/or high indoor co2 levels.

If ph is still low with outside aeration tests then your alk and or ph testing is probably incorrect.

 

[DrZoidburg]

CO2 at 400-1000 seems average. That is a lot of kalk dosed in 24 hours. I would consider comparing it to another device. What are you using to monitor are these 2 probes using the same system? Is there a boat load of corals? There are other things that can lower ph additive wise. I would think you should be over 8.0 dosing all of that 24/7?

 

[Herby’s reef]

First, what are you using to test your pH? Second, what does the pH peak at during the day?

I have a hydros and an Alkatronic. Both probes calibrated. Have also double checked with a Hannah ph checker, although I know the accuracy is not super great on those. Still, it matches. On a good day it peaks at 8.22

 

[Herby’s reef]

CO2 at 400-1000 seems average. That is a lot of kalk dosed in 24 hours. I would consider comparing it to another device. What are you using to monitor are these 2 probes using the same system? Is there a boat load of corals? There are other things that can lower ph additive wise. I would think you should be over 8.0 dosing all of that 24/7?

I do have a lot of coral. Sps I. A 50 gallon low boy and it is full, and the main display is 130 gallon full of torches. Both connected to the same sump. I am using an Alkatronic and a hydros. I calibrated ph probes using a liter of rodi spraying over the probe between each reference solution. They both show very accurate ph with a new packet of reference solution. Also the Hannah ph checker. The reagent one that looks like a normal Hannah checker, is very close. I do dose the 11 liters of kalk every day. 24/7 on a versa pump through an avast stirrer. I also dose 2 part soda ash and calcium chloride

 

[blaxsun]

It sounds like you're doing everything possible with your pH. My pH peaks @8.10 and dips down to @7.95 at night (monitored through an Apex and tested periodically with a Hanna).

 

[Herby’s reef]

CO2 at 400-1000 seems average. That is a lot of kalk dosed in 24 hours. I would consider comparing it to another device. What are you using to monitor are these 2 probes using the same system? Is there a boat load of corals? There are other things that can lower ph additive wise. I would think you should be over 8.0 dosing all of that 24/7?

I do have a lot of coral. Sps I. A 50 gallon low boy and it is full, and the main display is 130 gallon full of torches. Both connected to the same sump. I am using an Alkatronic and a hydros. I calibrated ph probes using a liter of rodi spraying over the probe between each reference solution. They both show very accurate ph with a new packet of reference solution. Also the Hannah ph checker. The reagent one that looks like a normal Hannah checker, is very close. I do dose the 11 liters of kalk every day. 24/7 on a versa pump through an avast stirrer. I also dose 2 part soda ash and calcium chlorode

It sounds like you're doing everything possible with your pH. My pH peaks @8.10 and dips down to @7.95 at night (monitored through an Apex and tested periodically with a Hanna).

i would be ok with your ph. I have read ph below 7.85 can harm coral. I keep losing sps colonies and torches with very stable alk. I send ati icp tests every 5 weeks. Got one back yesterday and it looks great. I think the ph has to be my problem. Everything was fine before the ph started dipping. It makes no sense to me. Why out of the blue, is it dipping like this so low. I have always had trouble, but I have been able to fix it before. Nothing I do seems to be helping now

 

[Herby’s reef]

Co2 and alkalinity.

As usual the easy way to confirm co2 is an issue is an outdoor aeration test. Assuming ph is then what expected for your given alk then you either need better gas exchange in tank and/or high indoor co2 levels.

If ph is still low with outside aeration tests then your alk and or ph testing is probably incorrect.

I don’t get much of a change with outside air aeration, which makes sense because I had an air exchanger installed in the house. I will double check this over the weekend though. I have not run the test in a bit. Assuming there is not a significant change, are there any other possibilities to cause it? I have tons and tons of flow. Unless my room air co2 monitor is off, my home co2 is not high. I have an older home with an air exchanger, so I tend to think it is not high.

 

[DrZoidburg]

I do have a lot of coral. Sps I. A 50 gallon low boy and it is full, and the main display is 130 gallon full of torches. Both connected to the same sump. I am using an Alkatronic and a hydros. I calibrated ph probes using a liter of rodi spraying over the probe between each reference solution. They both show very accurate ph with a new packet of reference solution. Also the Hannah ph checker. The reagent one that looks like a normal Hannah checker, is very close. I do dose the 11 liters of kalk every day. 24/7 on a versa pump through an avast stirrer. I also dose 2 part soda ash and calcium chloride

Time for calcium reactor, and kalk? I see no reason out of the blue to get low ph levels unless something acidic was added. Your pretty much borderline at night where its almost at the point it will dissolve calcium. How fast did it happen? Any correlation to house heat kicking on?

 

[mdb_talon]

I don’t get much of a change with outside air aeration, which makes sense because I had an air exchanger installed in the house. I will double check this over the weekend though. I have not run the test in a bit. Assuming there is not a significant change, are there any other possibilities to cause it? I have tons and tons of flow. Unless my room air co2 monitor is off, my home co2 is not high. I have an older home with an air exchanger, so I tend to think it is not high.

If it stays really low even fully aerated outside that would indicate innacurate tests.

 

[Herby’s reef]

Time for calcium reactor, and kalk? I see no reason out of the blue to get low ph levels unless something acidic was added. Your pretty much borderline at night where its almost at the point it will dissolve calcium. How fast did it happen? Any correlation to house heat kicking on?

It does seem to happen with the weather change, but not super cold here yet, so not much heat going. I had a calcium reactor before, but ph was super bad then

 

[mdb_talon]

Time for calcium reactor, and kalk? I see no reason out of the blue to get low ph levels unless something acidic was added. Your pretty much borderline at night where its almost at the point it will dissolve calcium. How fast did it happen? Any correlation to house heat kicking on?

Sounds like he already does a lot of kalk. A perfectly tuned calcium reactor at best has no impact on ph, but more commonly is going to drag down ph so i dont think that is a good approach

 

[Herby’s reef]

It does seem to happen with the weather change, but not super cold here yet, so not much heat going. I had a calcium reactor before, but ph was super bad then

Oh, and to be honest I’m not positive it happened fast. Thinking back, I noticed it when I recalibrated my probes, so possibly it has been bad a while and I did not know. Really hard to say for sure

 

[arking_mark]

My ph dips to 7.75 at night and i truely believe it is causing my corals issues. I don’t think it is due to excess co2. My room air co2 monitor only shows co2 in the 500 to 600 range. I have an outside air exchanger with the output just over the tank. I have outside air going to a co2 scrubber going to my skimmer. I dose 11 liters per day of saturated kalk on a 180 gallon system. How is my ph still low? Oh, and I have two ph probes that I have calibrated multiple times and they show to be accurate in reference solution. I am going crazy trying to figure this out!! It has not always been this low, but I have always struggled with this, hence the air exchanger and all the stuff.

If your indoor CO2 air quality is 600ppm and your Alk is at 8, your calculated low would be around 8.13 NBS.

So your absolutely correct that something doesn't add up assuming you believe your measurements.

If your tank doesn't have enough aeration, this could be the cause.

A simple cup aeration test could help identify the issue.

 

[DrZoidburg]

Sounds like he already does a lot of kalk. A perfectly tuned calcium reactor at best has no impact on ph, but more commonly is going to drag down ph so i dont think that is a good approach

To compare to 3 meters though that all say similar? This maybe a situation where corals out grew kalk, maybe co2, or something acidic is getting in. Keep in mind scrubber, and fresh air are not keeping up. If well tuned reactor should be pretty stable. Try dosing ph increasing additives at night?

 

[C. Eymann]

Whats the fish load like? if high, that can be a factor, also if atmospheric CO2 levels have been dealt with/ optimized (scrubber, binding CO2/ carbonic acid with kalkwasser additions to create carbonate and bicarbonates)

Are you feeding heavy ? esp with high fish load nitrification/ denitrification create mildly acidic byproducts.
Also carbon dosing (vodka, Nopox, biopellets) can have the same effect and decrease pH.

 

[mdb_talon]

To compare to 3 meters though that all say similar? This maybe a situation where corals out grew kalk, maybe co2, or something acidic is getting in. Keep in mind scrubber, and fresh air are not keeping up. If well tuned reactor should be pretty stable. Try dosing ph increasing additives at night?

Either excess co2 in the water(for whatever reason) or faulty tests those are the answers. Agree calc reactor if well tuned should be not a big impact, but it will never help a low ph situation.

 

[Herby’s reef]

Whats the fish load like? if high, that can be a factor, also if atmospheric CO2 levels have been dealt with/ optimized (scrubber, binding CO2/ carbonic acid with kalkwasser additions to create carbonate and bicarbonates)

Are you feeding heavy ? esp with high fish load nitrification/ denitrification create mildly acidic byproducts.
Also carbon dosing (vodka, Nopox, biopellets) can have the same effect and decrease pH.

I do have several big fish. I have certainly seen plenty of tanks with more though. I don’t feed super heavy. I use hpd and mastic, so not much wast. I feed my corals often, but I would not say a crazy amount.

 

[Herby’s reef]

To compare to 3 meters though that all say similar? This maybe a situation where corals out grew kalk, maybe co2, or something acidic is getting in. Keep in mind scrubber, and fresh air are not keeping up. If well tuned reactor should be pretty stable. Try dosing ph increasing additives at night?

I have thought of doing the kalk at night. Just not sure what that would do to my alk levels. I will play with that a bit though