Should I test fro ALK at the same time each day?

cracker · Feb 27, 2018

Hello,I have been looking for my tanks daily use of ALk & dosing accordingly. Ok, Tested five days every night about 8pm. I was also dosing 10 mls in the morn & 10 late afternoon . I took an average of the readings & came up with 7.6. I'm shooting for 8.0 so I will start dosing 12 mls ,twice a day.
My question should a do my daily alk tests at differing time in the day or is it ok to test at the same evening time ? Thanks
I use Ocean's blend 2 prt & test with a Hanna Checker.

Mrx7899 · Feb 27, 2018

I test at the same time

Randy Holmes-Farley · Feb 27, 2018

It is not critical to measure at the same time of day, since alk only steadily declines, but it is important to measure at the same or at least an understood time in relation to when you dose (which is most easily satisfied by the same time of day measurement if you dose at a fixed time(s) of day).

Remember that the alk will be appreciably lower right before a dose, and higher right after. If you want to aim for 8 dKH, does that mean 8 is the minimum, or the average, or the maximum? Only you can decide exactly what you want to accomplish with dosing.

cracker · Feb 27, 2018

Thanks Randy,! I'm wanting 8.0 as an average with .5 swing in either direction.

anthonys51 · Feb 27, 2018

Randy is alk only consumed by corals when the lights are on. I have a calcium reactor. Was wonder if I tested in the morning my alk would be higher than at night since the corals didn’t consume alk during the night. It does lights have nothing to do with alk consumption

Randy Holmes-Farley · Feb 27, 2018

anthonys51 said:
Randy is alk only consumed by corals when the lights are on. I have a calcium reactor. Was wonder if I tested in the morning my alk would be higher than at night since the corals didn’t consume alk during the night. It does lights have nothing to do with alk consumption

Alk demand often appears higher when lights are on, according to a number of folks with automatic measurements through the day and night, some who see nearly all the demand during the day, and some who just see more then. But that may be because pH is higher then, as opposed to lights actually being on.

It's an interesting question as to exactly why, since both abiotic precipitation and coral calcification will be higher at higher pH, but the coral calcification may also happen partly because of light. Sop there are three possible reasons, and at the moment, no adequate data to distinguish them. of course, it may vary by tank as well, since the relative amount of coral calcification and abiotic precipitation will vary a lot.

cracker · Mar 2, 2018

so 20 mls a day, I got an average of 7.6 after another 5 days dosing 24 mls of prt's 1 & 2, twice a day I got,an average of 7.8 . so now I'm going for 30 mls ,twice a day. I believe this will over shoot my goal of 8.0 . We shall see ! This really is interesting & a lot of fun ! I assume You "Tank of the month" folks have been here before, Make room causeI'm moving in !