Stabilizing alkalinity problems

[djperezo]

For these past 3 months, I'm having problems stabilizing alkalinity in my 55g. Everytime I slowly stabilize it using Seachem's reef builder to about 8dKH and using limewater as top-off to keep it stabilized, in a couple of days, it goes back down to 5-6dKH. I've always thought that dosing kalk as top-off should keep ca and alk stabilized. Ca always stays the same, 400-420ppm, am i doing something wrong???

 

[Randy Holmes-Farley]

Probably not. You may just not be meeting the demand for alkalinity in the aquarium (it rises as pH rises). Can you describe what is in the tank? How high does the pH get?

 

[djperezo]

Thanks for the quick response, as for tank inhabitants, I have 4 clams, about 14 sps frags, ranging from 1" to 3" 4 different LPS corals ranging from small to med size. and the various zoos, and 1 rbta. As for fish, I have 2 percs, and 2 purple gobies. And the pH reaches its high at 8.0 during the day.

 

[Randy Holmes-Farley]

The limewater may not be meeting the demand. How much limewater is added each day? How much lime in it? I assume the top off is added slowly?


If you are replacing all evaporated water with saturated limewater, then you can boost the addition with fans that increase evaporation, or you can consider adding more solid lime to the limewater (3 teaspoons per gallon), and add 45 ml of vinegar per gallon of limewater.

Alternatively, you can just use a two part additive in addition to the limewater.

 

[djperezo]

I currently just mix 1 tsp per gallon and in a 5 gallon jug, and top-off is about 1 gallon/day (all top off water is saturated limewater). I will follow your advice and increase kalk per gallon and leave fan on at night to increase top off, thanks for the advice, and I will let you know the results.

 

[Randy Holmes-Farley]

I'd first just try 2 teaspoons per gallon, maybe without the fans, to see what that does.

 

[djperezo]

Ok, yesterday morning, before this thread, Alk was at 6 dKH, I slowly brought it up to 7 dKH as of this morning. As for top off, I'm going with your recommended 2 tsp per gallon, should I still add vinegar? will leave off the vinegar for now, thanks.

 

[Randy Holmes-Farley]

I'd wait on the vinegar too.

 

[baruchbl]

I have two questions:
1) How much precent is the viniger?
2) Can i take some salt water from my tank and mix them with kalk and thd viniger and put it back to the tank drop after drop?
Its can dissolve in the tank too?

 

[Randy Holmes-Farley]

Most distilled white vinegars in the US are 5% acetic acid. They often say 5% acidity on them.

Can i take some salt water from my tank and mix them with kalk and thd viniger and put it back to the tank drop after drop?

I probably would not do that. It will take a large amount of vinegar to keep the pH low enough to prevent the precipitation of magnesium hydroxide and calcium carbonate. Bacteria in the water will also start to consume the acetate as soon as the vinegar is added. That will produce CO2, lower the pH more, and use up oxygen. Still, it might work if there was a strong reason to do so.

 

[djperezo]

Ok this morning, I checked dKH again and it dropped to 6 dKH, so now Im gonna slowly titrate this up again to 8dKH and use the 3 tsp lime, and 45cc vinegar per gallon. Randy, do coralline consume a lot of bicarbonate/ca? I forgot to mention above that all 3 sides of my tank and rock is completely and thickly covered, layer upon layer, and also I have a shallow sand bed if that means anything.

 

[Randy Holmes-Farley]

Yes, growing coralline can be a large sink for calcium and alkalinity.

 

[baruchbl]

Do i can take kalk and mix it with some saltwater from the tank and put it back slowly to the tank (without viniger)?

 

[djperezo]

<a href=showthread.php?s=&postid=6836037#post6836037 target=_blank>Originally posted</a> by baruchbl
Do i can take kalk and mix it with some saltwater from the tank and put it back slowly to the tank (without viniger)?

Won't there be more precipitation, and less dissolved kalk in doing this?

 

[Randy Holmes-Farley]

Do i can take kalk and mix it with some saltwater from the tank and put it back slowly to the tank (without viniger)?

I wouldn't. When adding lime to seawater you will precipitate magnesium hydroxide immediately, and calcium carbonate more slowly.