ALK Swing????

[scytale]

Okay so I had insomnia last night, and decided to test my water parameters way later than I normally do...and found my ALK to be much lower than expected!!!

12/21/06
My CA/and ALK levels had been holding pretty stable the past 3 weeks.
Alk: 10-10.2
CA 420-430

Then I went on vacation for 10 days....
1/1/07
found no major calamities when I returned (just some rampant algae growth on the glass)
but ALk was down to 9.6 (from 10.2; which I kind of expected since I wasn't around to add anything to buffer for 10 days....)

1/3/07 (insomia time)
Then last night when i tested my ALK it was down to 8.2, and still @ 8.2 again this morning!

I know my ph swings at night.
(usually from 8.3 at peak photoperiod down to 8.0-8.1 in the morning before photoperiod restarts...)

And so I guess it could make sense that my ALK would also swing because it's tied to pH, but is that normal???

I'll test my ALK when I get home tonight (to see if it swung back up, or if it's on a downward trend.)

As far has the rest:
salinity fairly stable @ 35-36 pptc
CA @ 420-430
Nitrites and Ammonia @ zero
Nitrates @ >10ppm (good for my tank)

The details:
CA and ALK testing done w/Salifert kits(other tests done with AquaPharm.) I have an 80 AGA w/o overflow. No sump/fuge, and I've never used any kalkwasser (yet). 90# Live Rock, prizm skimmer, fish (2 tangs, 1 chromi, 2 gsm), a huge LTA, some xenia, a few mushrooms, some candy cane and trumpet coral...

Finally, what's "the best" ALK level?
(I know stability and ionic balance are key) but is 10.0 better than 8.0?
Or as long as it's stable and in range, then it doesn't matter???

 

[DonW]

Sounds like normal consumption. 8-10 is fine, it sound like its time to start thinking about dosing.

Don

 

[scytale]

By dosing, do you mean Kalk, or ALK buffer?

I was dosing with Randy's 2 Part Ca/Alk recipe when I first got the tank in Oct.
But that was to bring the CA levels up from 350 (good ole' IO salt mix).

But when Dec. came around, I stopped dosing because everything was holding steady w/o dosing....

 

[Ed Hahn]

If your Alk and Calcium swing real fast check your magnesium. The three play together quite nicely.

 

[4251cpd]

DW and EH are the money. A few answers from you will help a bit better:

1. Tank size

2. Salt mix used

3. Type of substrate

4. How often and how much do you do in water changes.

 

[scytale]

It's an 80 gallon.

w/ IO mix.

SSB--1-2" of coarse Argonite (I think.)
I bought the tank as is--all included...but it's got the same coarseness that I've seen as Argonite.

I usually do 20-25% water changes every 1-2 weeks....though I haven't done one since the week before Xmas (I used all my RODI water before I left for vacation, and now I need to refill, resalt, and reheat my barrells...will be doing one as soon as the water is ready...probably tonight!)

 

[4251cpd]

Try the water change, see if that helps. Was an experienced salty dog feeding your fish while you were gone? Reason I ask is that people who have never kept fish tend to over feed. The uneaten food decays causing the buffering to be used up by the newly introduced acids into the system. A bit dumbed down but that was the way it was explains to moi.