Alkality dropping fast

[CK Reef]

Hi guys,

I'm experiencing a problem. My alkalinity is dropping quite fast in  the recent 2 days. Normally, I dose only 15ml each of the 2 part everyday to keep my alk at 7.8 and calcium at 480. But in the recent 2 day, I had to triple the dose but my alk still 7.2 and calcium is about 420-430. The only different recently was adding 2 nems and a maxima clam. Was it a problem or my corals starting to consume more alkalinity? Nothing wrong with the tank yet but I'm just trying to make sure it wouldn't be anything wrong.

Thank  you guys.

[zygote2k]

Are your corals and/or coralline algae visibly growing?

[Origami]

How big is your tank and what is your magnesium level? Low magnesium can make it difficult to maintain high calcium/alkalinity.

[khh27]

I've noticed from keeping clams that dosing requirements increase drastically with clams... but that could just be me

 

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Edited August 11, 2016 by khh27

[Origami]

I've noticed from keeping clams that dosing requirements increase drastically with clams... but that could just be me

No, it's not just you. Clams, if they're growing or if they're large relative to the tank size, can be big consumers of calcium and alkalinity. So can fast-growing corals (as hard corals grow, their consumption will increase exponentially). 

 

Darkseeker, are you also seeing a corresponding drop in your calcium level as your alk drops (ideally, it'll drop 20 ppm for each 1 meq/l, or 2.8 dKH, of alk)?

[CK Reef]

My system is 150G and Mg 1300. got about 40 frags, a big birdsnest about 13-15", 2 acans, a 10 head frogspawn, and some other softies. I was dosing about 15-20ml a day but i'm tripling it now to keep my Alk and Ca at the right level. Did the clam really take up that much?

[Origami]

My system is 150G and Mg 1300. got about 40 frags, a big birdsnest about 13-15", 2 acans, a 10 head frogspawn, and some other softies. I was dosing about 15-20ml a day but i'm tripling it now to keep my Alk and Ca at the right level. Did the clam really take up that much?

It could. Just running some really rough calculations, 15 ml of BRS's alkalinity two part (assuming it's around 6165 dKH - from their forumula) is totally consumed if 1.6 grams of calcium carbonate skeleton is laid down. Using Wikipedia's entry for density of aragonite (2.8 grams/cc), that's a volume of little less than 0.6 cubic centimeters of new aragonite being laid down for every 15 ml dosed. If the clam is fairly large and growing, it could be a major consumer. That big birdsnest could also be a major consumer, too, as they can take off sometimes.

[Tom202]

Magnesium must be low

 

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[CK Reef]

Nope, Mg level is the same. Adjusted dosing to 65ml a day (originally 15-20ml) and it's stable now . didnt think the clam could take that much....