Very low PH

[Jen_h]

I tried a CO2 scrubber at one point and didn't like it. It worked, but would have been very expensive to maintain and was labor intensive. Media needs to be changed out very regularly. Sometimes in under a week.

I mix up fully saturated kalkwasser in a 5g container and dose 1400mL per day spread out over 70 doses. That isn't enough to make up for all my alk/calc demand so I dose the remainder using BRS 2-part. Adding that much volume in kalkwasser also means less demand on my ATO system so it goes longer without needing to be refilled.

That makes perfect sense, thank you. May try that and return the co2 scrubber.

 

[Auto-pilot]

Ok another question for everyone. How does the increase in O2 change the PH. If the PH is low due to CO2 creating carbonic acid why does Increasing O2 bring up O2. Does it help break the bonds somehow??. Simply does the freash air draw the CO2 out of the water? Acording to Henry's law running fresh air is going to increase oxygen but not decrease co2... I'm confused with this prossess

 

[Brew12]

Ok another question for everyone. How does the increase in O2 change the PH. If the PH is low due to CO2 creating carbonic acid why does Increasing O2 bring up O2. Does it help break the bonds somehow??. Simply does the freash air draw the CO2 out of the water? Acording to Henry's law running fresh air is going to increase oxygen but not decrease co2... I'm confused with this prossess

You are correct in thinking that increasing O2 does not bring up pH. Fully aerated water can only hold a certain amount of gas. By running less CO2 in the air you are saturating the water with you will end up with less CO2 in that water. The oxygen content is completely irrelevant. You could run pure N2 through the skimmer to displace the CO2 currently in the water and reduce introduction of new CO2 to get the same impact.

 

[Auto-pilot]

Ok so here is my next question then if your alkalinity is at 140 but PH is at 7.8 the only explanation is that your co2 is high? How do you raise PH without effecting Alkalinity at the same time, just add a better source of O2. Sorry questions I've just never fully understood this

 

[Jen_h]

Ok so here is my next question then if your alkalinity is at 140 but PH is at 7.8 the only explanation is that your co2 is high? How do you raise PH without effecting Alkalinity at the same time, just add a better source of O2. Sorry questions I've just never fully understood this

That’s kinda why I’m stuck in a rut. Makes sense though what brew was saying on dosing kalk along with 2 part. Definitely a better solution then how I was running kalk. Felt like it was also to inconsistent through the ato

 

[Auto-pilot]

I guess asking more specifically are there other causes to a low PH in a system that has an adequate amount of carbonate other than carbonic acid? I've always had a system that runs at 8.0 7.9, which is low and think I would get better results with coral growing with a higher PH. Never been able to make it happen. I looked into lye as a way to add a base without changing Alkalinity and I think it would raise PH but only by converting g co2 into CO3

 

[Jen_h]

This may totally be off the wall but I think I read something about if you have low ph, corals don’t consume a whole lot of alk. In return grow at a much slower rate.
I do have corals encrusting and growing but don’t know if it’s at a fast rate or not. First time doing an sps dominant tank.
I do know that I stopped testing twice a week because the alk was still within range every time I tested so there was no point in dosing literally 1 ml.
For example last week when I had tested, it was 10 days from my last test. I was letting things go because I really wanted to see how long it was going to take for the alk to start dropping.
When I tested it was 6.7. I dosed to raise it back up to 8. 5 days later which was yesterday it was at 7.8. I use the Hannah checker and always test more then once. As many corals I have in this tank it was weird that there’s barely any alk consumption. I know this doesn’t seem possible but sometimes I feel like they burn through calcium faster then the alk.
Like I said probably totally off the wall but I did want to mention it since it seems kind of funky.

 

[Jen_h]

Here’s a video of the tank and how everything looks with my low PH problem. Sorry whites are already off by the time I get home

 

[Auto-pilot]

Here’s a video of the tank and how everything looks with my low PH problem. Sorry whites are already off by the time I get home

It looks good! I have something similar butI feel like my little frags would actually grow if my pH was higher

 

[Jen_h]

It looks good! I have something similar butI feel like my little frags would actually grow if my pH was higher

Lol I know what your saying, that’s why I’m trying to figure out why my ph is so low and if it’s hindering their growth.
At the same time though like they say if it’s not broke don’t fix it....so I have mixed feelings about all of this!

 

[ReeferNtraining]

Alk consumption, Calc consumption and pH are all connected. If you raised your pH to 8.3 for two days your dKh would fall thru the floor. If you can keep it at 8.2 consistently, you would clearly notice faster growth. I am only stating my observations with my systems and experimenting with CO2 scrubber, baking soda and soda ash.

 

[Brew12]

I looked into lye as a way to add a base without changing Alkalinity and I think it would raise PH but only by converting g co2 into CO3

Since CO3 is carbonate, and carbonate is a constituent of alkalinity, this would be increasing pH by raising alkalinity.
In a reef tank there are only two factors that impact pH. Alkalinity and CO2. If you know your alkalinity and your pH you can calculate the CO2 in the water. In the same way, if you know your CO2 content and your Alkalinity, you can determine your pH. No other factor is significant.

The only reason fresh air works to raise pH is that fresh air should have less CO2 in it than stale air in your house.

As for how much pH impacts coral growth, that is hard to say. The difference between 7.5 and 8.4 is probably pretty large and will make a big difference. The difference between 7.9 and 8.2? Probably no something you will notice. There are many other factors that will impact SPS growth in a more significant manner than pH. I believe flow to be the single most important thing to get right to grow SPS. 2nd would be stability, especially with alkalinity. I would try to keep alkalinity within a 0.5dkh range for weeks at a time. 3rd would be lighting. Not even sure I would call pH 4th. I would make sure I have the other factors right before I stress pH too much.

 

[Auto-pilot]

Since CO3 is carbonate, and carbonate is a constituent of alkalinity, this would be increasing pH by raising alkalinity.
In a reef tank there are only two factors that impact pH. Alkalinity and CO2. If you know your alkalinity and your pH you can calculate the CO2 in the water. In the same way, if you know your CO2 content and your Alkalinity, you can determine your pH. No other factor is significant.

The only reason fresh air works to raise pH is that fresh air should have less CO2 in it than stale air in your house.

As for how much pH impacts coral growth, that is hard to say. The difference between 7.5 and 8.4 is probably pretty large and will make a big difference. The difference between 7.9 and 8.2? Probably no something you will notice. There are many other factors that will impact SPS growth in a more significant manner than pH. I believe flow to be the single most important thing to get right to grow SPS. 2nd would be stability, especially with alkalinity. I would try to keep alkalinity within a 0.5dkh range for weeks at a time. 3rd would be lighting. Not even sure I would call pH 4th. I would make sure I have the other factors right before I stress pH too much.

Yes! These things I do know. I have flow down right now. I have a wavemaker and 4 power heads that do a great job.
My alkalinity stays at 140-145 or at least it had been every time I look. I was thinking about dropping it to 7dkh it's about 8 right now. 7 is 120ppm apox I think.
Lights......led fixtures. Probably my biggest weak point but they work for now.
I just think that if I get PH up it might help me out alot as my SPS are growing. My lps are nuts just need to work on my SPS game is all.
You definitely answered my question with the relationship between alkalinity PH and CO2. That answered my question that I never really understood. It's a direct relationship. The More CO3 you have the more negative charged particles and the more CO2 the more positive ions or hydrogen ions there is to make the pH go down. It all makes sense!

 

[Brew12]

Yes! These things I do know. I have flow down right now. I have a wavemaker and 4 power heads that do a great job.
My alkalinity stays at 140-145 or at least it had been every time I look. I was thinking about dropping it to 7dkh it's about 8 right now. 7 is 120ppm apox I think.
Lights......led fixtures. Probably my biggest weak point but they work for now.
I just think that if I get PH up it might help me out alot as my SPS are growing. My lps are nuts just need to work on my SPS game is all.
You definitely answered my question with the relationship between alkalinity PH and CO2. That answered my question that I never really understood. It's a direct relationship. The More CO3 you have the more negative charged particles and the more CO2 the more positive ions or hydrogen ions there is to make the pH go down. It all makes sense!

This is the equilibrium equation showing how Carbonic acid, bicarbonate and carbonate are tied together.
H2CO3 <--> H+ + HCO3- <--> 2H+ + CO3--

 

[Auto-pilot]

Thanks that also helps. I feel like Ive allways only seen peices to the realtionship not the hole picture

 

[vetteguy53081]

I wouldn't fret, Ive been running similar numbers (not by choice) well over a year and my tanks look great

 

[Randy Holmes-Farley Verified Community Expert]

Ok my question for you guys is can you just use Lye or sodium hydroxide in order to break the bonds of the carbonic acid?? Co2 creates an acid that lowers the PH, if you add baking soda or carbonate the PH will go up but also the alkalinity which might not be desired. Could you just use Lye to disociate the carbonic acid and not effect anything else???

Sodium hydroxide is an alk additive that has the highest possible pH boost per unit of alk added. About twice as much as sodium carbonate.

The “break the bonds” part isn’t perfectly accurate from a mechanism standpoint, but it is probably a useful way for a nonchemist to think if it.

 

[Randy Holmes-Farley Verified Community Expert]

I wouldn't fret, Ive been running similar numbers (not by choice) well over a year and my tanks look great

pH 7.3? IMO, that’s pretty suboptimal.

 

[Auto-pilot]

Sodium hydroxide is an alk additive that has the highest possible pH boost per unit of alk added. About twice as much as sodium carbonate.

The “break the bonds” part isn’t perfectly accurate from a mechanism standpoint, but it is probably a useful way for a nonchemist to think if it.

Or more so the carbonic acid looses two protons

 

[ACF930]

I had the same issue and even lost a couple frags when PH dropped into the 7.5. I recently increased my PH by 0.3 to 0.4 by adding a CO2 Scrubber, Air Pump with Air stone in the sump, and dosing Kalk at night.

To save on soda lime media, I installed the scrubber outside my house and hooked the Air Pump to it too. Noticing a difference in coral health now.