What is stable alkalinity?

[Trever]

Is my alkalinity stable? What is considered a "swing"? What is reasonable changes in values to consider it "stable"?

What about moving between 7 - 6.6?

I have a 38 gallon (total water volume) system. I've recently added first corals (9 days ago and then 3 days ago), there's 5 frags in there, though one is perhaps not a frag and more of a birds nest small colony (about 2.75" all around, quite a few little branches). SPS (no acropora), monti, and a cyphastria.

At the time I added corals, alkalinity was 7.0

It's slowly drifted down I guess, reading just now was 6.6. I noticed my weekly 10% water change bumped it from 6.8 to 6.9 (this was 4 days ago).

I'm aware it's on the low side. But for this small a tank with so little coral in it (plus 4 small fish), I'm wondering if I should do anything yet (two part, etc.). I would have guessed that water changes would sustain the tank for at least 6 months before I would have to start adjusting. Then the question is if I try to keep it at (say) 7.

Note: wasn't measuring alk until adding coral and still haven't tested calcium, have to get over the activation energy to use that complicated Red Sea measuring kit! My alk kit is the Hanna.

 

[Doctorgori]

Kalkwasser, and All for one are two thing you could try. I like Kalk and use it regardless anymore. Two part implementation could be tricky for small tanks but I’ve seen it done...
Opinion vary but .3 to .5 over a week isn’t probably gonna kill anything...I’ll press 1 full point in 1 wk up past that I dunno....
bumping this for more opinion/ sample size

 

[Montiman]

I would also consider a different salt mix if you are hoping to replace elements with water changes. I worry about an alk lower than 7dkh so using a salt mix that mixes at 8 dkh will give you more of a buffer before you reach uncomfortably low levels.

 

[Trever]

@Montiman gotcha. I'm using RS Blue Bucket, which actually mixes at 8 if my memory serves.

 

[Montiman]

In this case a 50% water change should move you closer to 7.5. I do not know why you would be at 7 before adding any coral unless this is what your salt mixed at. If you really want you can use something like RedSea Black bucket in which case water changes alone may be enough.

 

[Trever]

I don't know why it was at 7 either, it was the first time measuring alk. The tank has been running for almost 3 months now. I had been doing relatively frequent 10% (once did a 20%) water change to lower nitrates. Salinity has always been 35. pH was low today, 8.0, but is usually 8.15.

For what it is worth, so far, the corals seem to be thriving. The purple stylo has colored up a lot in the last several days, has huge polyps, and the forest fire digitada has visible growth. The newer 3 day old corals seem to be settling in, meaning they look fine or better each day so far.

 

[Trever]

Google points back here:

What do you consider to be stable Alkalinity in your system?

With all the hoop-la recently around Alkalinity monitoring what do you consider to be stability when it comes to your Alkalinity levels. Think of the values as +/-.

www.reef2reef.com

 

[Randy Holmes-Farley]

Is my alkalinity stable? What is considered a "swing"? What is reasonable changes in values to consider it "stable"?

What about moving between 7 - 6.6?

That's adequately stable, IMO. Might some corals be even happier with more stable values? Maybe.

 

[Trever]

@Randy Holmes-Farley thanks.

Just in case, I ordered the Kalkwasser starter kit from BRS. I may start dosing kalk into the ATO (Tunzie), we'll see. @Montiman asks a good question, given my salt and all the water changes, I'm not sure why my alk is low. With Kalkwasser, could maybe inch values up, but everyone says don't chase numbers. The corals are thriving, so not going to do anything sudden.

 

[Mical]

What are you using for test kits?

 

[Trever]

@Mical

pH - salifert
alk - Hanna
calcium - Red Sea (I haven't actually checked this yet, will do that prior to dosing anything and hopefully get to this today)
nitrate - salifert (also have a Red Sea that I have used once- using up the salifert first)
phosphate - Hanna LR (not the ULR, unfortunately- that LR checker is a nuisance)

 

[Mical]

@Mical

pH - salifert
alk - Hanna
calcium - Red Sea (I haven't actually checked this yet, will do that prior to dosing anything and hopefully get to this today)
nitrate - salifert (also have a Red Sea that I have used once- using up the salifert first)

Copy that... Personally as mentioned I would slowly bring Alk up also check Cal & Mag. Many folks overlook magnesium.

 

[nkusumoto]

Hello all,

I'd stick with Red Sea test kits if you feel more comfortable doing it yourself, but Hannas are quicker to a certain extent and maybe more accurate than our human eye. I test at least every day or every other day on my 1 month old Red Sea 525xl reefer since its new and I did a transplant from my 8 year old AIO 50 gallon established reef tank. Test always around the same time and dose around the same time. So keep a notebook handy.
My parameters are:
Alk 9dkh
Calc 450ppm
mag 1360

IMPORTANT do not raise all over 1.0dkh every 24hrs, learned my lesson with my beach bum Monti and crazy rr Monti. Ended up getting STN. The worst.

Once you get the hang of it you can dose without even the need for testing every day, you can push to a twice a week.

I personally do not test my phosphate or nitrates as much as I should but always handy to have one when things look funny.

 

[Bradley Creek Reefer]

I can’t keep birds nest. They loose their color within a few days of being in the tank then start STN. My current try is good flow, and about 300-375 PAR. Will a .05 Alk swing kill them and or other SPS? Acros are doing fine. Euphillia at the bottom are doing fine.
Alk-9 plus or minus .02 with an occasional swing around .04 about once a month. Not sure why I can’t get that straightened out. I have a Tridant with DOS too.
Cal-330
Mag-1350
Salinity-35
Temp-85
Ph- 7.8-8.15