ALK dropping massively

[expo703]

25gal IM lagoon

 

Last week my alk was 6.4 I did a 10 gallon water change and it was 7 the next day I tested.

 

A week later I tested and it was 6.5.. (I have all for reef so I was about to start dosing it weekly) however yesterday I did a 10 gallon water change with tropic pro salt (alk of 7) I tested alk today its 5.9 wtf is going on. My corals are not happy and I don't have much..I don't see them soaking up that much alk within a week is this normal? What else would be using all my alk my other parameters seem okay:

 

Param:

Alk 5.9

Calc 440

Nitrate 0

Mg 1440

P04 0.1 (I have been running Phosguard but can't seem to keep it lower than 0.1) I barely feed do 10 gallon water change a week.

 

 

 

[Zer0]

Well how much coral do you have in the tank? Any other inhabitants that soak up alk like clams? Also what is your daily evaporation rate like? And what is your pH?

[Tamberav]

How old is the tank? Bacteria, algae, etc all actually use alk. Alk tends to do wonky things in young tanks. 

 

Did you test your freshly mixed salt too? Salt mixes sometimes mix low as well due to various factors. 

 

When did the corals start to look unhappy? What do you test phosphate with?

 

I ran my tank at 5.0 alk and never had unhappy corals from it and know of at least one badass acro tank that runs theirs 4.8-6ish. However swings could make corals unhappy and phosguard can as well if it causes PO4 to swing or there is a PO4 testing error. 

 

I would also double check salinity with a freshly calibrated refractometer. 

[expo703]

Almost a year old. No clams 3 fish two clowns and a wrasse. Does vibrant drop your alk? Used hanna checker. Prob little less than 5 gallons a week of evaporation

[Tamberav]

I don't have experience with vibrant but it is a form of bacteria and mystery stuff 😅. It would seem possible though... I just have no idea how much effect it would have. 

 

Do you have any way to verify the hannah checker is working correctly? Have you calibrated it recently? I believe hannah recommends once a month. 

 

I am guessing salinity is fine since Calcium looks ok but I always double check that first.

[expo703]

The alk hanna checker? Yeah should be fine its only been used like 15 times or so

[FISHnChix]

Are you actually testing the alk of your premixed wc water?

[Micro-Reefs Aquariums]

8 hours ago, Tamberav said:

How old is the tank? Bacteria, algae, etc all actually use alk. Alk tends to do wonky things in young tanks. 

 

Did you test your freshly mixed salt too? Salt mixes sometimes mix low as well due to various factors. 

 

When did the corals start to look unhappy? What do you test phosphate with?

 

I ran my tank at 5.0 alk and never had unhappy corals from it and know of at least one badass acro tank that runs theirs 4.8-6ish. However swings could make corals unhappy and phosguard can as well if it causes PO4 to swing or there is a PO4 testing error. 

 

I would also double check salinity with a freshly calibrated refractometer. 

Can you expand on Alk changes based on Bacteria or Algae or combo of both?  Thanks

9 hours ago, Zer0 said:

Well how much coral do you have in the tank? Any other inhabitants that soak up alk like clams? Also what is your daily evaporation rate like? And what is your pH?

Can you expand on evaporation on Alk?  Thanks

[Tamberav]

13 hours ago, Micro-Reefs Aquariums said:

Can you expand on Alk changes based on Bacteria or Algae or combo of both?  Thanks

Can you expand on evaporation on Alk?  Thanks

By algae I mean the calcified kind, like coralline taking it up. 

 

The conversion of ammonia to nitrate and nitrate depletes alk. The consumption of nitrate (naturally, not water changes) gives back that alkalinity. 

 

So young tanks that are producing more nitrate may see a down trend of alk and those that are aged or consume Nitrate it in some process may see an upswing of alk. For tanks that have to dose nitrate, you would be boosting alk slightly. Balanced tanks would see no difference since the alk would drop when converted to nitrate but then return when nitrate is processed. 

 

I am no technical chemist but that is how I understand it from this article: 

 

http://reefkeeping.com/issues/2004-12/rhf/index.htm 

[blasterman]

Many biological processes consume alk including the nitrogen cycle. Alk is rarely stable at all.

 

A box of baking soda and the online reef calculator fixes the problem. Pretty simple. Pretty cheap.

 

If alk is depleting I would target a higher value like 9 dKH.

[Micro-Reefs Aquariums]

If seeking a higher Alk, I know Red Sea Coral Pro has a very high alk 12 dkh to start with.  You can start adding that as a buffer until you find the root of the problem. 

[blasterman]

Or reef Crystal's. These mixes have higher default alk components and are designed for younger tanks.

 

All for Reef should never be used except in mature tanks with very stable alk and calcium uptake. 

[Micro-Reefs Aquariums]

I personally use RedSea SPS dominant which has a Alk of 8.0, I can bring it up if I like, I have wiggle room unlike Coral Pro which I believe is really high and if I go higher by mistake I can kill my SPS.