Low PH, ionic imbalance?

[XLOR8T]

so I had to treat my tank with Melafix as I have a fish with suspected eye infection. I normally had ph of 7.7-7.8 35ppt salinity at 8-8.4DKH. Low point being after nopox dose drop to 7.65-7.68

With no skimmer I added 2 big air stones. ORP at 420. But ph steadily dropped to 7.55-7.6. My fuge with medium size chaeto used to raise ph but now also have brown algae spreading in fuge even on the chaeto. Tried increasing light from opposite to additional 3-4 hours in am. No change

I dosed ESV and raised Alk to 9.5 temporarily increased ph to 7.75 then steady drop back to 7.55.

Cal is now at 450 mag 1580-1600. I’m wondering if the ca/mg ratio has anything to do with it. Need to get ph up as I’ve been told low ph is irritating the fish eye infection.

I use Red Sea blue bucket salt. 140gal total water.

Thanks in advance.

 

[Diesel]

With airstones going can you get outdoor air to the pumps?
Outside air is lower in Co2 (about 300 ppm)
But indoors about 1000 or more, all that Co2 you pump in your water.

 

[XLOR8T]

With airstones going can you get outdoor air to the pumps?
Outside air is lower in Co2 (about 300 ppm)
But indoors about 1000 or more, all that Co2 you pump in your water.

Too far from from outdoor and there’s no “in line” so I can even try to go get a co2 scrubber. But my skimmer would have been pulling in the same air. If anything it was making more bubbles than a air pump.

 

[Randy Holmes-Farley Verified Community Expert]

Cal is now at 450 mag 1580-1600. I’m wondering if the ca/mg ratio has anything to do with it.

No.

pH in seawater is determined only by carbon dioxide and carbonate alkalinity.

I'm not sure why your pH declined. The melafix contains organics that may decompose to CO2, but there may be other reasons as well.

I'd also recalibrate the pH meter before worrying much, as they claim is does not alter pH.

 

[XLOR8T]

No.

pH in seawater is determined only by carbon dioxide and carbonate alkalinity.

I'm not sure why your pH declined. The melafix contains organics that may decompose to CO2, but there may be other reasons as well.

I'd also recalibrate the pH meter before worrying much, as they claim is does not alter pH.

I have a seneye and apex. Both reading same ph and did a manual Red Sea test.

I left all the door and windows open for 6 hours and negligible difference in PH. Only up to 7.65 Is there a buffer that will raise ph without raising KH too much.

Also I read somewhere about my fresh water ph for top off. I have solid 250-GPD rodi system. Should I be measuring ph in my top off water?

Thanks.

 

[Randy Holmes-Farley Verified Community Expert]

I have a seneye and apex. Both reading same ph and did a manual Red Sea test.

I left all the door and windows open for 6 hours and negligible difference in PH. Only up to 7.65 Is there a buffer that will raise ph without raising KH too much.

Also I read somewhere about my fresh water ph for top off. I have solid 250-GPD rodi system. Should I be measuring ph in my top off water?

Thanks.

The pH of your RO/DI water at 0 or 1 ppm TDS is not a cause of low tank pH, no matter what pH it reads). Adding totally pure fresh water at pH 7.0 to seawater at pH 8.2 will actually raise the pH of the seawater. It's nonintuitive, but perfectly understood. This link shows why:

https://www.reef2reef.com/threads/m...tion-question-yes-you-want-this-title.361380/

There is no possible way to add something to raise pH and not raise alkalinity. Hydroxide (as in limewater or in my newer DIY two parts using sodium hydroxide) have the highest possible pH boost per unit of alkalinity added. It works by consuming CO2 to form bicarbonate

OH- + CO2 --> HCO3-

If fresh air in the room did not help, either the measurement is in error, the alk is super low (way below 6 dKH), or the tank is not well aerated with the air in the room.

IMO, despite the two tests "agreeing", the first is by far the most likely.

 

[XLOR8T]

The pH of your RO/DI water at 0 or 1 ppm TDS is not a cause of low tank pH, no matter what pH it reads). Adding totally pure fresh water at pH 7.0 to seawater at pH 8.2 will actually raise the pH of the seawater. It's nonintuitive, but perfectly understood. This link shows why:

https://www.reef2reef.com/threads/m...tion-question-yes-you-want-this-title.361380/

There is no possible way to add something to raise pH and not raise alkalinity. Hydroxide (as in limewater or in my newer DIY two parts using sodium hydroxide) have the highest possible pH boost per unit of alkalinity added. It works by consuming CO2 to form bicarbonate

OH- + CO2 --> HCO3-

If fresh air in the room did not help, either the measurement is in error, the alk is super low (way below 6 dKH), or the tank is not well aerated with the air in the room.

IMO, despite the two tests "agreeing", the first is by far the most likely.

I guess the two big air stones are no replacement for a skimmer. I will test with Red Sea kit again for ph manually.

If I use Kalia and bring up the alk is water changes the only way I will get it back down? I like to aim for 8 or below.

 

[Randy Holmes-Farley Verified Community Expert]

I guess the two big air stones are no replacement for a skimmer. I will test with Red Sea kit again for ph manually.

If I use Kalia and bring up the alk is water changes the only way I will get it back down? I like to aim for 8 or below.

What is kalia? Kalkwasser? It has only a temporary effect on pH, until more CO2 replaces what was consumed. Aquaria also usually also consume alkalinity, so many folks (myself included) dosed it every day for alkalinity and calcium. Water changes can lower alk, but the new salt water likely also has low pH if mixed in the same house as the tank is in.

One way to determine the source of the CO2 and/or if the measurement is off is described here:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

 

[XLOR8T]

What is kalia? Kalkwasser? It has only a temporary effect on pH, until more CO2 replaces what was consumed. Aquaria also usually also consume alkalinity, so many folks (myself included) dosed it every day for alkalinity and calcium. Water changes can lower alk, but the new salt water likely also has low pH if mixed in the same house as the tank is in.

One way to determine the source of the CO2 and/or if the measurement is off is described here:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

Sorry I meant kalk. Auto correct changed it.

I will do a aeration test this weekend before I do a water change. My mixed salt water is typically at 8-8.2 ph and that brute has a pump in the bottom. Not a ton of aeration.

 

[XLOR8T]

What is kalia? Kalkwasser? It has only a temporary effect on pH, until more CO2 replaces what was consumed. Aquaria also usually also consume alkalinity, so many folks (myself included) dosed it every day for alkalinity and calcium. Water changes can lower alk, but the new salt water likely also has low pH if mixed in the same house as the tank is in.

One way to determine the source of the CO2 and/or if the measurement is off is described here:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

Edit (I did not do aeration test properly. Will have to repeat).

I also have to find a way to dose nopox slower to reduce ph lowering properties. But i still have very low ph.

So I did the fresh saltwater aeration in the house and ph was 8.1 with Red Sea test kit. (Will have to repeat) Couldn’t do the outside aeration test as last two days have Been super hot and I couldn’t maintain same temp as tank.

I did a 30% water change and my ph came up to 7.9 but steadily dropped from 10am to 8pm and is now at 7.6. I did dose 4mil of nopox in a 140g volume which usually does a dip but recovers. No rebound yet.