Dosing Question

Longnose Hawkfish · Jun 20, 2015

I use the BRS two part dosing in my mixed reef and I have been getting an annoying pattern. Right now I am trying to determine a pattern to my tank but I can not figure out alk for the the life of me. Let's say my numbers are Ca 405 ppm and KH is 7 dKH. I want Ca 440 and KH I want at 8 dKH. I do the recommended dosing according to the brs calculator and split up my dose in three days. On third day i test my water and calcium will be perfect but my alk goes down to like 6 dKH. It happens every time I does Ca and alk, but when I just dose alk the numbers go up fine. I does Ca at 10 am, Alk at noon, and then Ca again at 6 pm for the three days. I am getting a pattern of dosing Ca causing a rapid loss in Alk. What should I do to stop this trend when I dose? Thanks!

Randy Holmes-Farley · Jun 20, 2015

I don't think it really has to do with the calcium dosing, even if it correlated with it.

FWIW, if you take 3 days to boost alk from 7 to 8 dKH (which, IMO, is unnecessarily slow), you should expect it will be lower on day 3 because of the 3 days of demand that didn't get accounted for.

Rather than chasing the calculator numbers up and down with every dose, I'd just pick a dose that you give every day. Then very slowly adjust it up or down to maintain alk where you want it. I might start at 1 dKH per day if you numbers you quote are close to reality.

Longnose Hawkfish · Jun 20, 2015

Ok thanks for the help. So, I should check my numbers and then randomly dose an amount that appears to be sufficient and then test numbers again and adjust from there?

NanaReefer · Jun 20, 2015

Look for possible precipitation of your calcium. A white build up on heater and pumps.

Longnose Hawkfish · Jun 20, 2015

Would calcium precipitation cause a loss in calcium not alk?

s2nhle · Jun 20, 2015

also try to dose the alk at night and cal during the day.

Downbeach · Jun 21, 2015

Make sure your Mg is between 1200 - 1400 ppm. Use this calculator, fill in the blanks for your system, select Randy's recipe #1 (soda ash) from the drop down menu's to get the required dosage. You can increase your alk up to 1.4dKH (25ppm) per day, your Ca up to 50 ppm per day. Once you are at your desired numbers, start to monitor/record for a few days to develop a trend line. To get your daily dose, divide the amount used by the number of days you tested. There's a little trial and error here since it's a little difficult to get the actual net water volume of a system, so some minor adjusting may be necessary.

Randy Holmes-Farley · Jun 21, 2015

Longnose Hawkfish said:
Ok thanks for the help. So, I should check my numbers and then randomly dose an amount that appears to be sufficient and then test numbers again and adjust from there?

Yes. Trial and error is the best way to get to a maintenance dose.

Longnose Hawkfish · Jun 21, 2015

My mag is like 1460 ppm. And ok cool, I will test today

KlynnUK · Jul 17, 2015

I tried to read my parameters without dosing to measure drops on these elements for week or two .. then refered to calculator and raised them slowly over couple of days but took me months to get it right and fine tune it.
This might not be an answer but it could have been reading,mg,or anything.. nice tank there..