Alk Serious Issue

[RockOn681]

I tested my water yesterday and went from having an alk of 7 a week ago to an alk of 16!!! In that time span all that has occurred is me topping off with 1 gallon of not very concentrated lime water. I don't know what happened and am planning on doing a 15% water change today. What should I do and what should I be worried about? Are my fish having a panic attack right now? I do not have any coral but am concerned for my fishes sake. What in my tank consumes alkalinity and how fast can I expect this value to decrease? Any advice would be appreciated.

[m2434]

Something sounds wrong? What do you mean by not very concentrated? How much lime was in it? How much water evaporated in that time? What is the total volume of your system? Did you check with a different test kit? If nothing in your tanks looks stressed, I wouldn't do anything too drastic, that may be more stressful. Your plan sounds fine to me. Also, what is your pH? Is there any cloudiness?

[RockOn681]

It was 1.5tsp in 1 gallon of water. The tank is 75 gallons plus around 15 gallons in the sump. I brought it in to the LFS to be checked, mind you that is not a guarantee that it's correct either. They of course told me not to worry about it. I have a few mushrooms in the tank that don't look super happy. I also have a small carpet anemone (yes I know it will get to big) They isn't any cloudiness to the tank everything looks crystal clear. My pH is 8.1. Thanks for your help, I am planning on a water change when I get home, mind you I am using instant ocean reef crystals and have read mixed reviews here about it. Some people say alk is too high some say it is just fine??? I don't know, I just don't want anything stressed (mostly the carpet).

[chuckreef]

From the sticky (top of the page): Adding 1/11,000 of the water volume as muriatic acid will drop alkalinity by 1 meq/l (2.8 dKH).

90/11000 = 0.0082 gal. 0.0082 x3785 = 31 ml for a drop of 2.8

So, you could would remove about a gallon of water to a pitcher. Then add about 50 ml to 60 ml of muriatic acid to the water in the pitcher (using safe handling practices) and then slowly drip that back into the aquarium over eight to 24 hours time. Monitor alkalinity every few hours using a test kit. If it drops by more than two or three units in twelve hours stop the drip. I would also stop dripping once alk is about 12; at that point you can let it just slowly come down on its own over the next few days (or weeks).

[RockOn681]

Few questions about that method. What is the concentration of the HCl being used in this procedure and wouldn't doing this also drop my pH? Or is the addition so small that it will effect alk and not pH that much?

[chuckreef]

I am not sure what strength acid Disc1 calculated the above ratio with.
Hardware stores usually sell the typical 30 to 34% grade ( would guess this strength). There is also a 15% grade usually used for swimming pools sold at hardware stores. If you are concerned you could use the weaker strenghth and repeat if needed (or use the stronger and cut the amount in half).

You will probaly see a pH drop, but the carbonate buffer system should keep the pH from dropping too low as long as you add the acid slowly. You could monitor this with testing or a meter.

[m2434]

Alk of 16 should come down pretty quickly on it's own. A few water changes will help. Personally I find swings to be worse than high alk. I wouldn't go adding a strong acid if you can't figure out how it got that high. What is your s.g. and how are you measuring? The alk in RC isn't that high. Adding 1g of "not so saturated lime" shouldn't raise it much at all. RC should be around 14dkh @ an s.g. or 1.026, so, the 7 may have been error, but the lime shouldn't have raised it. So, I can't see how you'd be more than 14 dkh or so, unless something else, such as s.g. is being measured incorrectly. Most likely there is some measurement error and no reason to do something fairly risky like adding a strong acid. What do you have for corals? can you try another test kit?

[bertoni]

I would let the alkalinity drop on its own, as suggested. Using muriatic acid is more trouble and danger than it's worth, IMO.

The most common way for the alkalinity to rise like this is the use of pH buffers, which all add alkalinity, despite advertising to the contrary. Another possibility is measurement problems.

[Chris27]

Are you sure you didn't mistakenly use baking soda instead of calcium hydroxide?

[RockOn681]

Yea pretty sure lol, I don't even have baking soda in the fish room at this point in time. I did my 15% water change last night and I honestly dont know where all that alk came from. I mixed up my water before I did the change and it had an alk of 10 or 11 dkH, so getting up to 16 had to come from somewhere. My water change brought the alk down to around 14 or 15 dkH and I will do another small one next week, but I really want to know how it got that high? I think I am going to avoid using HCl. I am a grad student and work in a research facility so I know I could get a pure 1M (1N) solution of it but feel it might be best to avoid putting anything else in right now. I was thinking all this could be from around 40 pounds of live rock I recently added to the tank but am unsure of that.

[m2434]

If your pH got low, perhaps some of the LR dissolved. It would have needed to get pretty low though. And seems unlikely if alk is that high. Tough to say without being there and knowing everything that's happened.


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