PH Levels

[jazzsam]

So, I have been having troubles keeping my PH up. It got down to about 7.9 and then I added some calcium (purple up) and it jumped right up to 8.02 and I was happy but a couple days later it is now down to 7.78! Now it is back up to 7.85 but I want it to stay around 8.0 to make me happy. What would "naturally" keep my PH up? I tried water changes and that does nothing also.

I know I don't have enough live rock in there but would that help keep my PH up?

 

[pnoyreefer]

My PH now is 7.89 with no lights and 8.1-8.2 when lights are on. Is your PH 7.78 when lights are on or off?

 

[jazzsam]

My PH now is 7.89 with no lights and 8.1-8.2 when lights are on. Is your PH 7.78 when lights are on or off?

It does go up a bit during the day but not that much. I have the Solaris LED lights if that makes a difference.

 

[pnoyreefer]

I dont know if it makes a bigg difference but I too are not happy with my PH.. I buff them with baking soda and it was back to 7.98 no lights and 8.2-8.with lights. I did a 15% water change yesterday and I am back to the levels I posted above. I will buff it again tonight

 

[DaveK]

Before you add more baking soda, keep in mind that it does take awhile to have it's full effect. I usually wait 2 days before I test and use it again if necessary.

Here is an excerpt from Stephen Spotte's book Captive Seawater Fishes, on how much sodium bicarbonate you should add to bring the pH up to 8.2. This is excerpted from table 1-9.

Initial pH --- Amount of sodium bicarbonate to add in grams per liter at 25 C (77 F)

7.5 0.117
7.6 0.110
7.7 0.101
7.8 0.0986
7.9 0.0751
8.0 0.0562
8.1 0.0317

Of course you need to convert the amount of water in you system to liters. Then multiply by the factor above, and weigh out the amount you need. From experience I can say that you don't need to be too accurate, but you should be close. If you need a quick way to measure grams, a US dime is about 2.5 grams, and a US nickel is about 5 grams.

You may be find you need to add quite a bit.

Lastly, if you you do this and find the pH quickly drops back to where it was, you likely have other water chemistry problems, no matter how much you dump in, it's not going to fix the problem. In that case, look into the brand of salt you are using and other additives you might be using. If the pH doesn't change at all consider that your test kit or pH probe/meter is bad.

 

[ham]

hey JAZZ i have the same light system but i havent had any ph problems always around 8.0-8.2 tested with lights on and with them off but i am having a problem with bleaching from the bottom up on some of my acro's my kh was high like 12 have since got it down to 9 will see what happens

 

[jazzsam]

hey JAZZ i have the same light system but i havent had any ph problems always around 8.0-8.2 tested with lights on and with them off but i am having a problem with bleaching from the bottom up on some of my acro's my kh was high like 12 have since got it down to 9 will see what happens

I just got that bleaching from the bottom up on my birds nest! I thought it was really strange becuase normally it would bleach from the top down! Do you think changing the kh will help me also with that?

 

[Carlo]

Baking soda will LOWER your pH NOT raise it. You need to use washing soda (baked baking soda) to raise it. Baking soda is sodium bicarbonate while washing soda is sodium carbonate. One is "bi" and the other is not. The main difference as far as we are concerned is that the baking soda has CO2 in it while the washing soda (baked baking soda) has the CO2 removed (why you bake it).

Dosing either sodium bicarbonate or sodium carbonate to change pH is a temp fix at best and your pH will "neutralize" back to normal within 1/2 to 1 day while the Alk affect will take 1 to 2 days.

Use buffers to increase or maintain alkalinity, not pH. If Alk is at a good level and PH is still low, then find the source of your increased CO2 or SO4 (sulfate) levels.

Dissolved CO2 is carbonic acid (soda water) and dissolved SO4 is sulfuric acid. Thus, both contribute to decreased PH levels.

SO4 is a by product of some types of anaerobic bacterial metabolism, and is also added if you use Epsom salts to increase magnesium levels. SO4 levels can really only be brought down via dilution (water changes). SO4 is NEVER the only source of decreased PH (unless every living thing in the tank is already dead). Dissolved Sulfate can contribute to decreased PH, but only as as an "assistant" to dissolved CO2.

CO2 is added by every non-plant/non-bacterial organism in your system, as well as being added when you use baking soda to increase Alk, or if you use a calcium reactor.

If your tank has good alkalinity in the presence of high dissolved CO2 (low pH), then it means your potential concentration of carbonate ions is already very high in your system, but many are "locked up" as bicarbonate. Free these bound ions and your pH will rise naturally.

The most widely accepted methods for increasing pH in systems with strong Alk levels are to use aggressive aeration, usually via increased skimmer capacity, water falls in sumps and to increase the air/water surface area and promote better gas exchange. For this to work most effectively, you must be subjecting the water to air with the lowest CO2 content possible (read outside air).

If Alk and pH are both low, then drip kalkwasser (lime) to increase both. Kalk is a great method, because the hydroxide reacts with bicarbonate to create two carbonate ions.

Kalk is a "permanent" dosing solution to increasing PH, because it actually reduces the concentration of dissolved CO2 in your water. Just remember that kalk also adds calcium and to a slight degree your Alk, so monitor these levels as well if using kalk.

If calcium levels are good, but Alk and PH are both low, then using baked baking soda (sodium carbonate) to buffer the tank will increase both PH and Alk simultaneously. However, if your system is a natural CO2 sink, then adding carbonate to raise the PH is a short term solution, because it does nothing to reduce the dissolved CO2 concentrations in your water, so PH will eventually drift back down.

Hope this helps even it was a little "heavy duty".

Carlo

PS running a refugium on a reverse light cycle (maybe with some overlap) will help to keep the pH levels more consistant.

Jazz, concerning the bleaching. It could be caused by numerous things but changing Alk levels is certainly one of them. I used to run my Alk at a dKH of 11 but after doing much reading and studying I've lowered my target dKH to 8 which is closer to NSW conditions (but still higher) and have noticed improvements.

 

[DaveK]

Baking soda will LOWER your pH NOT raise it. You need to use washing soda (baked baking soda) to raise it. Baking soda is sodium bicarbonate while washing soda is sodium carbonate. One is "bi" and the other is not. The main difference as far as we are concerned is that the baking soda has CO2 in it while the washing soda (baked baking soda) has the CO2 removed (why you bake it).

...

The above statement need some additional clarification.

I have been using baking soda for years to adjust pH, so I wondered about Carlo's statement. I had to do some digging, but here is what is going on.

Sodium bicarbonate (baking soda) will initially slightly lower pH when it's use. Once the extra CO2 is gassed off processed etc, pH will rise. This is why you should wait a couple of days before you test pH again.

See this excellent article (offsite link) on the subject - http://www.advancedaquarist.com/issues/may2002/chem.htm

 

[Carlo]

Got to be careful how you read that Dave. Your clarification needs clarification. It won't "raise" your pH at all but will "normalize". This isn't what Jazz wants or should do since it will only lower his pH and never increase it since he has decent alk levels.

Example with made up data, let's say you start with alk of 8 dKH and pH of 8.00. You could use either sodium bicarbonate or sodium carbonate to raise your alkalinity. An addition of either of these will raise the alkalinity because you are adding buffers to the tank. If you add sodium bicarbonate (baking soda) your pH will initially drop a little and then eventually rise back to 8.00. So it will rise but not normally past where you started UNLESS the reason it was low in the first place was because the alkalinity was VERY LOW. In this case it was 8 dKH (plenty high enough) so the pH equalized back to where it started from.

Now had the person added sodium carbonate (washing soda) to raise the alkalinity the opposite would happen pH wise but with a greater extent. The pH would sky rocket and could get dangerously high quickly. You really need to drip additions of sodium carbonate or add it in small increments and watch the pH so it doesn't change more then 0.20 every few hours. Once the sodium carbonate has been in the system the alkalinity will rise as it should because of the buffer being added. Just as with the addition of sodium bicarbonate (baking soda) the pH will adjust itself back to "normal" and will drop back to 8.00.

So as you can see neither sodium bicarbonate or sodium carbonate SHOULD be used to adjust pH. You use them to adjust ALK but not pH since any change you see is only temporary.

Many Alkalinity Buffers on the market use about 5 parts sodium bicarbonate to 1 part sodium carbonate, sometimes with other additions like borate. The mixture at these two ratios pretty much keeps the pH about the same while raising the alk buffers in the tank.

The pH measurement is pretty complex and only somewhat feeds off alkalinity. If your alk dKH is 6 or higher then any pH problems need to be found elsewhere. Usually the number one cause of low pH problems in aquariums is caused by excess CO2 in the tank which usually is caused by a bio-load that is to high for the tank at present.

What you really want to do long term is (off the top of my head):
1. Remove some fish if possible. less fish = less CO2
2. Create more air exchange by having the top layer of water moving more (i.e. powerheads pointed at the surface). Maybe install a small hob power filter.
3. Create waterfall type water action in the sump
4. Grow macro algae and maybe run it on an opposite light cycle so the refugium lights are on when the overall pH is the lowest. The creates more of a balance.
5. Shorten the tank lighting period
6. Run the tank a couple of degrees colder. Obviously keep the tank in safe "reef" temperatures but on the colder side of the scale. The colder the water the more oxygen it can hold. The colder the water the slower the metabolism is of the fish and of course less CO2 is given off.
7. Use outside air to power your skimmer. Your house will normally have a much higher (3x or so) amount of CO2 in it then you will find outside.
8. Run UV and/or ozone which indirectly helps to raise pH.
9. Improve skimming or add other methods of organic removal from your system (install sponges or filter socks and clean them regularly).

Then there are "daily" things you can do that require ongoing maintenance like running kalk (lime water). If your calcium is under 420 and alk is under 9 this is an excellent way to help with calcium, pH and to a less degree alk.

If an only if alk is low then a drip of sodium carbonate (washing soda) can be used but you definitely need to watch the amount you drip and target a alk dKH of 9 or 10.

After you do as many of the long term things you can to help improve the pH then go with the "drip" method. If you drip, target the drip during the low pH times which is normally at night.

 

[Carlo]

Dave go back and read the section in that article under "Alkalinity Supplements":
"In a reef tank that is permitted to equilibrate its total CO2 levels with the atmosphere, these additions (bicarbonates, carbonates) all end up with the same final pH."

"This is an important result: in seawater in equilibrium with the atmosphere, for a given alkalinity there is a single pH that results, regardless of what was added to get to that alkalinity."

Randy's article is pretty good but he could have explained a few things better. If you already understand what pH is a measurement of then it all makes sense but I don't think he explains it good enough for the average person to grasp and understand. I don't think he ever even mentions what pH is, only how pH and Alk "play together".

For example if he explained that pH is a logarithmic measure of hydrogen ion concentrations and then explained that a little it would help to understand that alkalinity only plays the part of a "buffer" to keep the pH from rising or falling. (not changing the pH but only a "buffer" to keep it from rising or falling). It would also have been of benefit if he showed how the addition of bicarbonates and specifically carbonates change the hydrogen ion concentrations short term before they equalize and therefore show short term pH changes. This misunderstanding of pH is the biggest cause of people dosing bicarbonates and carbonates to change pH when in fact it does nothing after the solution has normalized with the CO2/O2 in the tank assuming there is proper buffers in the system (IE alk dKH of 6 or higher). He touched on it with:

"This is an important result: in seawater in equilibrium with the atmosphere, for a given alkalinity there is a single pH that results, regardless of what was added to get to that alkalinity."

But it's not really clear to the average reader. It would have been more helpful if he explained how adding more of either bicarbonates or carbonates actually just gives you more "bound up" carbonates long term.

What you really need to do is go back to the "hydrogen ion concentrations" measurement (pH) and then look for ways to use the "bound up carbonates" to change the hydrogen ion concentration by looking at SO4 (sulfuric acid) and CO2 (carbon dioxide) levels and how to adjust them.

Carlo