Help me rise the pH in my tank?

[Mgoc]

Ok, so this is the situation. I am battling dinoflagellates and I tried to kill them by increasing the pH in my tank using Kalkwasser to achieve a pH of 8.5. It did the trick!! No dinos were in sight for about 5 days but I had to stop dosing Kalk since my Ca was just short of 500.

Dinos came back and my Ca is still high. I know my home has enough CO2 to keep my pH on the lower side of the scale but I can't open the windows cause I live in the midwest and it' pretty cold outside. I was thinking about using baking soda or Sodium carbonate but I read that you should only use it when CO2 is not high in your home.

Aeration is pretty good, I use a skimmer and I have a couple of powerheads aimed towards the water surface to aid in gas exchange and I also have a refugium which should help with Oxygen levels right?

What other method can I use?

Thanks in advance for your help!

 

[Randy Holmes-Farley Verified Community Expert]

500 ppm calcium is not a big deal (many salt mixes are even higher) and it won't get much higher no matter how much limewater you add because alkalinity will rise and you'll begin to precipitate calcium carbonate.

The bigger concern may be how high the alkalinity got. Are you tracking it?

Sodium bicarbonate is a fine alkalinity supplement, but doesn't raise pH in the short term. Sodium carbonate will boost both pH and alkalinity, but has about half the pH raising effect of limewater per unit of alkalinity.

You could consider sodium hydroxide instead of limewater, but that wouldn't be better than limewater, IMO.

 

[jolt]

The idea of sodium hydroxide intrigued me, but in q quick search I couldn't find anything on people using it on reef aquariums. If I understand correctly the byproducts of that dosing could be just sodium chloride and H2O, is that correct?

 

[Randy Holmes-Farley Verified Community Expert]

And boost alkalinity, yes.

Aquavitro sells a product (ignore their ridiculous claim that it doesn't alter alkalinity):

aquavitro . balance

 

[UK_Pete]

Randy, is there a way to raise pH without raising alk, once your CO2 is at zero? I mean I guess adding OH raises pH but also raises alk, and reducing CO2 converts bicarbonate to carbonate. But once all the bicarbonate is carbonate (which I think implies no CO2 in the water), if your pH is still too low, what does this mean (if you are happy with your alk)? Does it mean that another buffer is deficient and needs to be added? I ask because even after aerating my water for hours outdoors, I still only hit 8.2. I would like to have around 8.5 or 8.6, so my alk can be reasonable (for ulns), and calcium sensible, but still be on the edge of abiotic precipitation, to 'push' lots of calcium carbonate precip (I want to see if that increases coraline growth).

 

[wangspeed]

I used to have PH problems. I ended up building a CO2 scrubber out of a juice bottle and a cheap source of soda lime. Keep in mind that your soda lime should be sealed airtight, or it will lose effectiveness over time. I prefer to buy them in small sealed bags online, though that may not help out UK_Pete.

 

[Randy Holmes-Farley Verified Community Expert]

If the CO2 is at zero in the water, the pH will be above 10, so you don't want that. CO2 in the water EXACTLY controls the pH, along with alkalinity. Together the two determine it mathematically.

Zero CO2 in the air just needs more aeration to take CO2 out of the water.

 

[UK_Pete]

Wang, thanks for that, as it happens I had just recently realised that a scrubber might be the way to go! Randy was helping me understand it in another thread.

Randy, I didn't realise that it was just CO2 that determined pH, thanks (I have been reading your articles before posting but must have not quite understood that point). I've just gone back and saw this:

At about pH 8.9 in seawater at 25 °C there are equal concentrations of HCO₃^- and CO₃^--.

If you aerated tank water strongly with air with zero CO2, would the pH rise to above 10 as you mentioned, or would the bicarbonate stop being converted to carbonate at some point before that?

Thanks, Pete

 

[Randy Holmes-Farley Verified Community Expert]

Randy, I didn't realise that it was just CO2 that determined pH, thanks (I have been reading your articles before posting but must have not quite understood that point). I've just gone back and saw this:



If you aerated tank water strongly with air with zero CO2, would the pH rise to above 10 as you mentioned, or would the bicarbonate stop being converted to carbonate at some point before that?

Thanks, Pete

Yes, the bicarbonate would disappear, then the carbonate would disappear as well, leaving hydroxide (assuming you didn't precipitate all kinds of stuff before that point).

2HCO₃^- --> CO₂ (blows off) + CO₃^-- (remains) + H₂O (remains)

CO₃^-- + H₂O --> CO₂ (blows off) + 2OH^- (remains)

 

[UK_Pete]

Wow never realised it could go that far (to OH)!

Now I'm worried about using a hood scrubber and taking out too much CO2 and making the pH rise too far.

I'm struggling to balance all the things i've read about the carbonate balance, and see how it would end up, if a tank has very little CO2. If you scrub the CO2 very efficiently from the aquarium air, especially if you are recirculating it as I am thinking at many lbs per hour, the pH will rise. So at a reasonable alk, the rise in pH will cause carbonate to precipitate, which will suck carbonate out, meaning theres more bicarb in comparison to the carb, so pH will fall back a bit. But will the precipitation of calcium carbonate act as a pH limiter here and keep pH to a safe level if you really strip the CO2 very efficiently? Or will the pH be in dangerous territory well before that happens?

Thanks, Pete

 

[Randy Holmes-Farley Verified Community Expert]

I don't think you'll be too successful to have to worry about that. Many creatures, like fish, are producing CO2 all the time.

Just watch the pH.

 

[reefndude]

I battled dinos and was successful. Not sure what actually did the trick, but this is what I did.

First siphoned out as much as i could. Then used a filter sock and lights out for 72 hrs. Dosed h2o2 during lights out...30 ml twice a day. I have around 150g of water volume.

After 3 days they were gone and never came back.

 

[Mgoc]

Thanks for all the help guys. reefndude, I tried the blackout and H2O2 with good but only temporary results, pH increase seems to work better for me. It this doesn't work I will use Fauna Marin's Ultra algae X.

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Good luck!

 

[Mgoc]

One last question. Randy, you said a 500 ppm Ca level is not a big concern since it will precipitate in the form of calcium carbonate when Alk rises. If it Ca kept rising, when should I be worried? At 600 ppm ot higher?

 

[Randy Holmes-Farley Verified Community Expert]

Calcium won't rise unless you are adding it, but in general, calcium of 550 ppm or less is fairly common and not a problem.

I'm not sure it really because a problem at somewhat higher levels unless you are unable to maintain alkalinity or are suffering too much precipitation on pumps, etc.

 

[JMSKI333]

I have heard of people running their skimmer air intake outside their home to pull in fresh air in areas where it is too hot or too cold to open the windows. Just an idea.

 

[that Reef Guy]

And boost alkalinity, yes.

Aquavitro sells a product (ignore their ridiculous claim that it doesn't alter alkalinity):

aquavitro . balance

I have seen you make this statement before.

But you never state how much it raises Alkalinity.

Have you actually tested this product or is it just an assumption that you are making?

I have been thinking about using it.

If you have tested it can you post your findings about how much it raises the Alkalinity.

I was using the Powdered Seachem PH Buffer but every time I used the recommended dosage my Alkalinity went up 1.8 to 2.0 (Which is a lot).

So I stopped using it.

Someone told me that Balance works great.

The only problem is you have to use a lot of it he said.

 

[Randy Holmes-Farley Verified Community Expert]

The Aquavitro product is a mix of potassium and sodium hydroxide (according the their web site). It is the hydroxide that boosts alkalinity, just as it does in limewater (kalkwasser).

It will boost pH by the exact same amount per unit of alkalinity as does limewater. That pH boost depends a bit on the actual alkalintiy and pH you start with, but is about 0.6-0.7 pH units per 0.5 meq/L (1.4 dKH) of alkalinity. The pH effect is temporary. The alk boost is permanent (until something depletes alk).

Yes, I have tested the effect of sodium hydroxide myself, although it is obvious to any chemist that it boosts alkalinity. I show the effect on pH here:

Chemistry And The Aquarium: The Relationship Between Alkalinity And pH ? Advanced Aquarist | Aquarist Magazine and Blog

 

[Mgoc]

I have heard of people running their skimmer air intake outside their home to pull in fresh air in areas where it is too hot or too cold to open the windows. Just an idea.

I know and you have no idea how much I would love to do that but the landlord would probably hate me for drilling a hole on the exterior wall.