Alkalinity Consumption Changes Weekly

[JAMSOURY]

I have 55 gallon water volume in my mixed reef and I’m dosing brs 2 part. I’m testing daily because of the fluctuations. I currently dose about 12ml of alk a day. But for the last few weeks, every time I think I get my dosage correct, my alk reads low and I have to raise my dosage by 1ml each week. So initially I was only dosing 9ml and I’m up to 12ml in three weeks. Any idea of what can be consuming it so fast that I have to raise it constantly?

Salinity 1.026
Alk 8.0
Ca 430
Mg 1300
Nitrate 10
Phosph 0.09

Thanks!

 

[gatorbait01]

Do you have sps? Maybe it's the corals actually growing and consuming more alk. I have a 36 gallon sps tank using brs 2 part and went from no consumption to ~50ml a day as my corals grew.

 

[ReeferReefer]

What corals do you have?

 

[JAMSOURY]

I have about 10 small sps frags all less than 1”. I also got zoas, a few small frags of acans, and an anemone. I understand that sps can consume a lot but is it weird that i would have to increase it weekly? Or eventually does it become stable?

 

[JAMSOURY]

Do you have sps? Maybe it's the corals actually growing and consuming more alk. I have a 36 gallon sps tank using brs 2 part and went from no consumption to ~50ml a day as my corals grew.

Whoa that’s a big difference. Were they frags of already colonies/mini colonies?

 

[reefwiser]

As corals grow so does their demands. You can also check you your alk readings by having a friend on a LFS check you Alk reading with their test.

 

[Ron Reefman]

Your dosing such small quantities I'd consider doing it less often for awhile, like every few days, and see how it goes. I have a 40g cube that is full of zoas and anemones (which don't use much alk or Ca if any at all) and only a few small sps and lps mini colonies. I test weekly and my alk goes from 9.5 down to 7.5 and I dose 125 to 175ml of swimming pool soda ash per Randy Holmes Farley's formula each week based on the testing. I dose all of that alk by dribbling it into the tank in front of a wavemaker. I do it in 3 or 4 segments spread out over 5 to 10 minutes while I'm doing other things around the tank. I've found bumping the alk from 7.5 to 9.5 once a week has had no ill effects on anything in the tank.

Your situation could be due to the growth of the stony corals. Maybe the alk you are dosing is becoming less effective over time due to settling? (that's a wild butt guess). In any event, I wouldn't worry about it as long as the corals look healthy and are growing.