Another test question for alk,calcium and mag

Hausser · Jan 19, 2016

So I have been trying to get my alk to 9.0 and stay as stable as possible, in the past I only hand dosed but recently I purchased a eshopps doser. I set it up to dose 50ml and to spread that amount 12 times a day. So yesterday I tested my water in morning with light off around 10:00am and then again at 5:00pm when lights have been on for a while, lights turn on at 2:00, so the 10:00am test showed my alk at 9.8 and the 2:00pm test showed 7.4. So my questions I have is should I test my alk with lights on or off and my second question is is it normal to have a 2.4 swing in DKH. In the past I only tested with lights on at 5:00pm. My doser doses every two hours starting at 12:00am. Tomorrow I am going to do the same test to see if I am getting the same swing in DKH. I understand that photosensithis happens when lights are on and that corals probably use more alk with lights on then off. Any help would be appreciated.

Randy Holmes-Farley · Jan 19, 2016

While there may be some difference tank to tank, the trend seems to show more consumption of alkalinity during the day.

FWIW, it is not photosynthesis that uses alkalinity, but calcification, so there's no a priori reason it needs to be during the day, but it seems to be..

It is certainly normal for alk to be depleted by 0.5 - 4 dKH per day, so it will swing by that much if you dose once a day.

So if you want to stabilize it more, you might want to dose from 2 pm to lights out.

Hausser · Jan 19, 2016

Thanks, I have been thinking about changing my dosing to try and keep it as stable as possible. I am one of those that want to keep my parameters as stables as possible. Doing this test also made me think that if I was one that wanted to keep my ALK at higher than 9 say 10 then it possibly could hit 12 or higher at night. My statement about photosynthesis was more towards that during the photosynthesis processes maybe the corals use more of nutrients than when lights are off. My doser is set to dose roughly 4 ml every two hours.

Randy Holmes-Farley · Jan 19, 2016

Here's a paper that shows that calcification during the day is 2.6 times faster than at night. They showed it by calcium uptake:

http://jeb.biologists.org/content/209/17/3413.long

Sabellafella · Jan 19, 2016

Yea i set my doser to run from 6 in the morning to 4 in the afternoon delievering 70% of my daily dose, then the other 30 from 8 till 12 at night. I was getting swings with my dosing pump and this seemed to do the trick

Roberto CRC · Jan 19, 2016

This subject interests me because these days I am about to put to work my dosing pump.

So how is the correct way to dosing Kh and Ca, day or night? and what percent of the dose in the day and the night?

Hausser · Jan 19, 2016

One thing to remember is dosing when lights on raises the PH.

Hausser · Jan 19, 2016

I that it was a great subject and I didn't realize I would have a large swing. I have asked multiple people including my LFS and no one could answer my question. I am glad that Randy can answer my question. I have thought about testing my water every hour for a day or two to see what my ALK does in a 24 hour period so I can dose my tank to keep my parameters in check. My next experiment will be calcium since I cannot keep my calcium above 360 using evs bionic calcium.

wcharon · Jan 19, 2016

Thats what i was going to say. Dosing ALK will raise PH which is where the PH is the highest. In my case i am getting PH up to 8.5 before lights out and 8.0 in the morning so i set my Doser on 11 intervals from 6am to 4pm to see what happens. I am also using full strength of KALK thru ATO for evaporation so that also affects.

I measure around 5pm when i get from work and i am targeting ALK of 8.0.

Randy am i OK with my route???? Also as the OP I want stable parameters because will experiment with SPS.

Randy Holmes-Farley · Jan 20, 2016

wcharon said:
Thats what i was going to say. Dosing ALK will raise PH which is where the PH is the highest. In my case i am getting PH up to 8.5 before lights out and 8.0 in the morning so i set my Doser on 11 intervals from 6am to 4pm to see what happens. I am also using full strength of KALK thru ATO for evaporation so that also affects.

I measure around 5pm when i get from work and i am targeting ALK of 8.0.

Randy am i OK with my route???? Also as the OP I want stable parameters because will experiment with SPS.

That sounds like a fine plan.