Puzzling... high ALK & Ca, low PH

[truebeliever71]

My chemistry seems to be all over the place after dosing sugar to reduce nitrates that were 60ppm. My ALK was also quite high at 300 KH (and still is.)

Now my readings are...
ALK 300 KH (same as before dosing sugar)
Ca 660 (was 400 2 weeks ago before I started dosing the sugar)
Ph 7.8 (was 8.4 " ")
Nitrates 20 (was 60 " ")
Nitrites 0
Amm 0

My corals look very good and happy. My blue snowflakes and wrinkle coral are growing like crazy, I have a toadstool frag that for the first week was looking very grim is now fully extended.

I started dosing the sugar because the tank has always had high nitrates even before I took it over from a former coworker and had heavy brown slime on the sand and starting growing hair algae.

Now the brown slim is greatly reduced but the HA is still growing strong. (And now I'm getting good coralline growth too.)

The tank is a 55g bow front and I do a 10 gal water change once a month (was doing 5 gal every 2 weeks.)

BTW... I've been emptying this very dark, gross, and nasty smelling skimmate out of my skimmer about every other day.... normally I have to empty it maybe every other week.

Any recommendations? Randy?

 

[Randy Holmes-Farley]

Are you dosing anything other than sugar to the tank?

The calcium result seems odd, and may be testing error.

What salt mix?

FWIW, the consumption of nitrate by bacteria will produce alkalinity for the tank. In this case, I do not know if that is the cause or not, but it may be contributing to a lack of a drop over time.

I should have provided this info to others who have seen similar things, but I failed to make the right connections. I show in this article that producing nitrate uses up alkalinity. Making 50 ppm nitrate will boost alkalinity by 0.8 meq/L (2.3 dKH; 40 ppm calcium carbonate equivalents). Likewise, dropping nitrate through bacteria or macroalgae produces the same amount of alkalinity.

When Do Calcium and Alkalinity Demand Not Exactly Balance?
http://reefkeeping.com/issues/2004-12/rhf/index.htm

 

[truebeliever71]

Randy,

Thanks for responding. Currently I used Instant Ocean salt mix (am/was thinking of switching over to IO's Reef Crystals since it contains about a 1 TBS more of Magnesium and other elements needed by corals.) The only other dosing I do is feeding the corals either "Coral Frenzy" or Kent's ZooPlex along with Coral-Vite once a week.

Like I said before, my ALK hasn't changed since dosing sugar... so I don't believe that the sugar is contributing to it.

Not sure if this has anything to do with this or not... but, when I first got the tank a few months ago it was a FOWLR tank... I moved a couple non-reef friendly fish and started adding the corals, about 30 Nassarius snails, 2 peppermint shrimp (there were lots of Aiptasia), and 2 blue legged hermit crabs. My corals consist of a large colony of green star polyps, green candy canes, frogspawn, ricordia mushroom, toadstool mushroom, blue snowflakes, purple wrinkle coral, and a kenya tree. Fish are 2 clowns, 2 blue damsels, and 1 green chromis.

Filtration is handle by a Fluval 304 canister with ceramic beads, floss, Chemi-pure bags (which are due to be replaced), and coarse foam. An AquaClear 50 PH with finishing filter and Phos-pad. And a Jebo 180 Skimmer.

Thanks again.

 

[Simon68]

Randy,
I had the same problem, been dosing Vodka to get my Nitrates down and my alk is off the charts. I am seeing a "snow" like substance on my rocks. Anything we can do to lower alk and still continue to dose for trates?

 

[Randy Holmes-Farley]

so I don't believe that the sugar is contributing to it.

No, but if you are not dosing alkalinity, it should be declining.

Maybe the kit is off? Io will run about 200 ppm in alkalinity, but not 300. Maybe the kit is off? Did you try the salt water itself?

maybe the salinity is not high, as you are also getting higher than expected readings for calcium in IO.

I had the same problem, been dosing Vodka to get my Nitrates down and my alk is off the charts. I am seeing a "snow" like substance on my rocks. Anything we can do to lower alk and still continue to dose for trates?

That might be calcium carbonate, but it might also be bacteria. Are you dosing anything else?

 

[Simon68]

No not dosing anything else other than Vodka. Anything I can do to get my alk in line and this ugly snow off my rocks?
Thanks so, so much, I really appreciate it!

 

[Randy Holmes-Farley]

How high was the nitrate? I have a hard time believing it is calcium carbonate if you dose nothing. if it is bacteria, stopping the vodka will diminish the growth of bacteria.

If you take some out, dose it dissolve in vinegar or other acids with bubbling? That would show it is calcium carbonate.

 

[truebeliever71]

<a href=showthread.php?s=&postid=13492915#post13492915 target=_blank>Originally posted</a> by Randy Holmes-Farley
so I don't believe that the sugar is contributing to it.

No, but if you are not dosing alkalinity, it should be declining.

Maybe the kit is off? Io will run about 200 ppm in alkalinity, but not 300. Maybe the kit is off? Did you try the salt water itself?

maybe the salinity is not high, as you are also getting higher than expected readings for calcium in IO.

I was thinking the same thing... so I have to different kits... one from Red Sea and I use the 5 in 1 test strips from Jungle... both have read very closely. I took a sample to my LFS and theirs read VERY HIGH. (Not much of a help I know.) My salinity is at 1.025 at 78 degrees.

 

[Simon68]

Nitrates were between 40 and 60. Not dosing anything else, will try the vinegar when I get home tonight. Thank you.

 

[Randy Holmes-Farley]

I would not believe test strips for alkalinity. Always look for a titration kit where you add drops until you get to a color change.

 

[Simon68]

I have been testing alk with API test where you add drops.

 

[truebeliever71]

<a href=showthread.php?s=&postid=13493270#post13493270 target=_blank>Originally posted</a> by Randy Holmes-Farley
I would not believe test strips for alkalinity. Always look for a titration kit where you add drops until you get to a color change.

I also have the Red Sea drops... registers 3.6 Meq/l

 

[bertoni]

Red Sea doesn't seem to be one of the more reliable brands, but the kit might be okay.

Are the growing corals stony? I'm not sure why the calcium isn't dropping. What's being used for top-off? RO/DI?

 

[truebeliever71]

<a href=showthread.php?s=&postid=13495383#post13495383 target=_blank>Originally posted</a> by bertoni
Red Sea doesn't seem to be one of the more reliable brands, but the kit might be okay.

Are the growing corals stony? I'm not sure why the calcium isn't dropping. What's being used for top-off? RO/DI?

I just used up my NO3 test kit and will getting a new one soon... I'm going to start switching over to the Salifert brand. Yes, my wrinkle coral (Coscinaraea columna) is a stony coral and the frogspawn as well are growing nicely.

 

[bertoni]

Then the calcium should be dropping without supplementation. I'm not understanding yet, unless the topoff water has a lot of alkalinity and calcium.

 

[truebeliever71]

<a href=showthread.php?s=&postid=13495529#post13495529 target=_blank>Originally posted</a> by bertoni
Then the calcium should be dropping without supplementation. I'm not understanding yet, unless the topoff water has a lot of alkalinity and calcium.

Top off water does have pretty high Alkanlinity (not has high has the tank) but little Calcium... besides, I haven't topped it off in a couple weeks since the tank is covered.

 

[Simon68]

Just to update my problem, tested all parameters tonight again.
Ammonia 0
Trites 0
Trates almost 0
Alk 15!
Tried scraping the "snow" off the rocks and it's impossible to scrape it to test it in vinegar, it doesn't really come off easily at all and when it does it just disappears into nothing.
Should I stop dosing vodka?
I am also in the middle of a major algea/diatom bloom. Ugh.
Tank is approx 5/6 mos old.

 

[Billybeau1]

Simon, is this "snow" just on the rocks or is it collecting on pumps and glass etc. ?

 

[Simon68]

just on the rocks

 

[Billybeau1]

O.K. and if you take a turkey baster, can you blow it off or do you have to scrape to remove it ?