My alk is low

BlackbMagic

BlackbMagic

AC Members
Sep 21, 2007
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Hi everyone i have just started my 55g tank back up after awhile with no lights just live rock and a couple of fish. i have 2 175 watt metal halides running 9 hours a day now and my tank is looking healthy. I added a small xenia coral and a small zoa colony a week ago. What i have been noticing is my alk is very low around 2.0 meg/l and my PH is 7.9. I am not sure on how to raise my alk? i would like to raise my alk to around 3.8-4.0 meg/l and i want my PH a little higher at 8.2? Does any one have any suggestions on what to do?



A quick side question... I have live rock in my tank that got ridden with algae months ago. while my lights were not connected it turned to brown dead detrius maybe. I have cleaned almost everything and have my cleanup crew but the clean rock started to turn a bright white with light light green hue. is this the start of new coraline? or what? The small patches of coraline i do have are doing fine and not turning white.
thanks
 
Easiest way to raise the alkalinity is to add Bicarbonate of Soda, its used in cooking and is sold in the supermarket. It is a pure substance and raises the alkalinity and the pH to a maximum of about 8.

There are aquarium powders and potions used to raise alkalinity but bicarbonate of soda is very cheap and easy. Just mix a little (for a 55g I would try 1 or 2 teaspooons) with freshwater and add it slowly to the tank and test the levels after about 15mins.
 
Thanks I mixed about a 6.6 tsp with a small amount of SW from my tank into a solution.This is the amount the reef chem calculator gave me so I will be adding is slowly over the next day or two as a precaution. Thanks for the response ill let you know how it works for me. Thanks again...
 
Ok, this is one of those things that has always puzzled me. Can someone explain what happens here?

Baking Soda directly into tank = lower pH but raises alk
Baking Soda cooked in an oven to make Soda Ash = raises pH and raises alk.

What does cooking the baking soda do to it to make it affect pH differently? Just curious.
 
Ace25 said:
Ok, this is one of those things that has always puzzled me. Can someone explain what happens here?

Baking Soda directly into tank = lower pH but raises alk
Baking Soda cooked in an oven to make Soda Ash = raises pH and raises alk.

What does cooking the baking soda do to it to make it affect pH differently? Just curious.
Click to expand...

Bicarbonate has an added hydrogen ion --> HCO3-

When that goes into the water, they dissociate and help form carbonic acid by dissociation of that hydrogen ion. Baked baking soda is CO3--, which is formed by driving off the bound CO2 and H20 in baking soda. What's left leaves you with just sodium carbonate. Carbonate itself is a strong base and will readily raise pH by immediately reducing the concentration of free hydrogen ions. If the hydrogen ions are bound up, then they can't create an acidic solution. Of course, the effect is temporary due to gas exchange. It will tilt back in the other direction somewhat before long.

Alkalinity refers to both the carbonate/bicarbonate buffer system for the most part. Other buffer systems are included, but none make as much of a difference compared to bicarbonate/carbonate. No matter which form you use, you are increasing the concentration of both bicarbonate and carbonate.
 
So maybe i shouldn't add the mix? I dont really need my ph going any lower...Or should i bake it? Im not to familiar with how this works although it makes sense. Ive never seen it done or done it before.
Soo... If i add the Baking soda to my tank it will raise alk and lower ph? if I then added a ph booster would it then stay constant because of the higher alk level?
 
The immediate effect will actually lower the pH. It may or may not rise slightly after that. If you need to actually raise your pH, then the baked baking soda (1 hr @ 350 F) is more along the lines of what you want. Be very careful, though, since small amounts raise the pH substantially. Personally, I would use a bit of that to raise the pH, then use a bit of plain baking soda to adjust the alkalinity further. That basically results in using a mix, anyway. In your case, skew the ratio of carbonate (baked baking soda) a bit higher to see if it gets you where you need to be.
 
Hey thanks alot that makes alot of sense. The problem still is though wont that just be a temporary solution? Am i going to have to constantly dose the tank? If thats the case are there any ways of finding out what is wrong with the tank that its that low in alk and ph? Or are those numbers normal as far as tanks not dosed for alk/calc/ph?
Sorry for all the questions im just trying to get ym tank running the best i can. Thanks alot everyone for your help :)
 
Yes, it's temporary, but that was never intended as a long term solution to begin with. It is more of a measure to keep the pH from falling too low while boosting alkalinity, not to maintain pH. If you are having chronic pH problems, I would suggest several things first: 1) increase aeration--this can be accomplished with good proteins skimming and lots of water flow, especially if it disturbs the water surface. Unfortunately, this principle relies on a lower concentration of CO2 in the surrounding air. If you have a lot of CO2 in the house and high production in the tank, it won't do you much good. 2) Increase photosynthesis--If you have a refugium, increase the lighting and water flow in its vicinity. This helps many tanks tremendously. 3) Use kalkwasser (calcium hydroxide or oxide)--this powder has a very high pH of around 10. When dripped continually it will not only directly raise the pH with the introduction of hydroxide ions, but it will readily react with most of the CO2 in the tank, creating alkalinity ions and raising the alkalinity, along with calcium. You have to be careful while dripping it, because it can raise the pH too much if done too quickly or too much. It also has the beneficial side effect of precipitating phosphate in the localized area of the drip.

All of these are much more permanent solutions to lower pH.
 
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