I Need Some HELP With My ALK!!

[ReefNightmare]

Hi, I 've never had this problem before, my ALK used to be around 11dkh before, and everything looked perfect,,, a few days ago I noticed some of my corals not being happy, in fact I lost a frogspawn colony, and two Fungias are not looking good right now,,so I checked my WP(Salifter)
Nitrate: undetectable
Phosphate:undetectable
Ca:470
Mg:340
dkh:below 7 :neutral:
Temp:79-81
Sg:1.025
ph:7.9-8.1
so I thought having the alk so low would be the cause of my corals being unhappy, I did a water change and it just raised it to 7.5,,then another WC and pretty much did not raise it much,
I ve been using limewater as a top off, today I checked again, and is below 7, I even used two tests
Salifter and API,both gave me the same results.
I don't use two parts dosing to dose Ca or Alk, I run a Ca reactor, but I was thinking,,
Can I use the alk dosing bottle from the two parts dosing, to raise my Alk?
Please I need some advice!!!

 

[TopNotchCorals]

Did you mean mg:1340??If not then 340 is definitely way too low.I don't think 7 DKH is deadly low on softies either.

 

[TopNotchCorals]

I would ditch the ca reactor and just dose 2 part as it is much more reliable and much more easy.

 

[ReefNightmare]

I m sorry I meant, 1340 ?

Did you mean mg:1340??If not then 340 is definitely way too low.I don't think 7 DKH is deadly low on softies either.

 

[Redstag]

I agreed with bayreefer. Dosing 2 parts is much more easy to control the parameter.

 

[RBursek]

ReefNightmare,
all looks good except the low end Alk, I would raise it to 9, using baking soda will raise it and leave your PH about the same or raise it slightly,Baked baking soda will raise it too put will raise your PH, to bake it spread it out on a cookie sheet, about an 1/8" thick and bake for 2 hours at 325* also your Alk 2 part. What salt are you using? What about your lighting? if the spectrum shifted on MH it could be the cause. Here is a chemical calculator. My tank uses about 1 DKH in Alk per day, and Kalk does not add hardly any Alk, it adds mostly Ca and at 12.45PH at full saturation will affect it to some degree.
Reef Chemistry Calculator

 

[beaslbob]

I notice you pH is a little low. If you are measuring it just before lights on (like in the morning) then I would do nothing and mesure pH and alk just before lights on. Could be both alk and pH will rise as carbon dioxide is lowered.

If the values are just before lights on then I would add a little baking soda. like a teaspoon for each 50g or so.

then remeasure a day later just before light out.


my .02

 

[RBursek]

Beaslbob,
I know when you bake baking soda you drive off the CO2 and when added to the tank it will raise Alk and PH, where un baked baking soda it will raise Alk and just a little raise in PH. Also when mixing up Randy's different recipes, with the 2 you are almost adding half as much of baked baking soda per gallon then baking soda, for the same Alk raise. But I do not think once your Alk is in your tank the Photothensises of the algae and lighting changing the PH of the water do to CO2 of the Algae will also change the Alk level.

 

[beaslbob]

There is (as you already know) an interplay between alk, carbon dioxide and pH.

an old article:

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

IME adding plant life to both Fw and marine systems that were previously plant free will result in an almost immediate rise in pH just before lights out. Well in about 24 hours or so anyway.
In a newly setup FW tank with a peat moss substrait setup ph was 6.5. A day later it was 7.2 then a couple of weeks later the "normal" 8.4-8.8 with the api test kit.

On one extreme case I did note a ph rise of 7.5 up to 8.2 in a day by adding baking soda. But a week later it was back down again. Tank conditions and fish health was terrible. (wasn't measuring alk then).

Upon adding macro algaes again pH was up to 8.2 the next day but rose to 8.4-8.8 by the end of the week and stayed there for years. Fish health improved tremendously.

I got calcium up to 400ppm or so but then noticed that my just before light on pH was down to 7.9 or so. With simple corals and fish things remained healthy.

When I started maintaining alk (and calcium and magnesium) with the diy 2 part, the nightly pH drop was much less to unmeasureable.

So from that experience I feel that it is imporant to first suck out the carbon dioxide with macro and other algaes so that the tank becomes a net consumer of carbon dioxide and producer of oxygen each 24 hour period. As reflected in high just before lights out pH reading.

Then get the alk up which will also prevent the nightly pH drop. but mainly provide (bi)carbonate for the calcium to help the hard corals, corraline algae, calculus algaes, clams and the like.

I find it worrying and curious that reefnightmare is dripping kalk and has low pH and low kh. But before I get all bent outta shape it is important to note when the measurements were taken.


my .02

 

[ReefNightmare]

Thanks for your help everybody!

 

[RBursek]

As BealBob argues an stated Vegie grow does help balance PH levels if you have a fuge/sump with Chatoe in it and run the lights on it opposite of your tank lights so the CO2 uptake and O2 levels can help be maintained and equalizes since Algae photosynthineses uses CO2 and give off O2. Ii have no experince in FW tanks as Bealsbob stated and do not know if they relate to salt water, but he is very knowledgable. I have also learned if the tank looks good and all other prams are good chasing PH is useless, it is what it is in your home with winter and summer if it is closed up and you have CO2 in the house, just doesing the different Alk recipes can help.