Kalk + Vinegar + Low Night PH

[chadm]

Ok,

So, I have been dosing Kalk at night to keep my PH at 8.1 - 8.2 during the night. I need to dose 1 gal of kalk a night to replace the Alk and Cal used during the day.

The problem is the Kalk raises the PH so well that only 1/2 a gal is used a night (using a PH controler to control the dosing pump) . So I was planning on using vinegar to decrease the PH of the Kalk (although very little) as well as lower the PH in the tank slightly while its being dosed so I can get all of the 1 gal in a night.

Is there any problem with this scenario?

Tank Specs:
50gal tank
Deltec MCE600 skimmer (is this enough to drive in O2 to offset the vinegar?)
Lots of surface aggitation

Stocking:
1x Damsel, 1x Coral Beauty, 1x 2.5" Scribbled Rabbit fish
SPS Dominate
Ball of Cheato


Best Regards
Chad

[Randy Holmes-Farley]

What pH are you using to cut off the addition?

[chadm]

Pump on at PH 8.0
off at PH 8.2

[Randy Holmes-Farley]

I'd move the "off" up to pH 8.5 or even a bit higher. Then you can probably deliver what you need and still protect against excessive pH. :)

[chadm]

Wouldn't the .5 point drop be a bit dramatic tho?

This is usualy how things tend to go in my system.

8.2 (morning) slowly rises to 8.4 (just before lights out 10pm) by 1pm its at about 8.1 to 8.0 (now kalk pump kicks on) throughout the night it goes 8.2 - 8.0 - 8.2 - 8.0 till finally 8.2 at about 10am *lights on*

When it comes to my PH controller it does not have a "on" - "off" position. Basicly it has approx a 2 pt differential .. so I set it to 8.0 and it comes on then at 8.2 it turns off..

So if I set my PH monitor to come on at 8.3 it will turn off at 8.5 ... is this good? Will the PH not rise super high by the time my lights turn off in the evening?

[Billybeau1]

Also if you want to get the whole gallon in at night, just decrease the amount of lime you mix per gallon. Say try one tsp instead of two per gallon.

[chadm]

but it takes 1 gal of Saturated lime water to make up the daily usage tho.

[Billybeau1]

O.K. then if you are worried about maintaining your levels then use 1 tsp per gallon and dose twice as long.

[Randy Holmes-Farley]

First, I wouldn't assume that if the pH gets to 8.5 during the addition, that it will drop all the way back to 8.0. The daily low will likely rise.

Second, I do not think that reasonable pH swings themselves are any concern. I do not believe that organisms adapt to pH changes on a diurnal basis. Their internal pH is tightly controlled and much lower than the seawater. So whether it is 8.0 or 8.5 through the course of a day is unimportant, IMO.

With respect to pH swings, I am much more concerned that the daily highs and lows do not pass out of the optimal range for organisms. So trying to keep it to 8.2 to 8.5 is optimal, IMO. Below 8.2, calcification becomes more difficult. Down to 8.0 is likely OK. Below 8.0 is rather undesirable, IMO.

[Randy Holmes-Farley]

When it comes to my PH controller it does not have a "on" - "off" position. Basicly it has approx a 2 pt differential .. so I set it to 8.0 and it comes on then at 8.2 it turns off..

Then I'd stop using the pH controller. Very few people actually use controllers with the limewater. I have a pH controller that I use only to measure pH, and I use limewater, but I do not control the limewater by pH.