no alk use for 3 days?

DFW · May 10, 2015

I have been testing alkalinity every evening for several months, so I am familiar with how much this system uses. But the last 3 days have been unusual in that testing shows basically no alkalinity being used. This makes me think that something might be wrong. I've been using the same test kit for 2 weeks. Lighting, and flow have been consistent. Magnesium, and temperature have been consistent. Does anyone have any ideas about what could be happening? Thanks!

Randy Holmes-Farley · May 11, 2015

How much does it usually drop?

What is the alkalinity?

DFW · May 11, 2015

Randy Holmes-Farley said:
How much does it usually drop?

What is the alkalinity?

It averages using 37 ml of your alkalinity recipe # 1 each day over the last 35 days. That includes the 3 days where it only showed using about 15 ml for the 3 day period. I am keeping alkalinity around 9 dKH right now. I am still manually dosing, so each evening when I test, I add the amount to my dripper that is indicated on this calculator to get it back to 9.2 dKH, mix it with 1 1/4 gallons of ro/di water, and drip it over night like I was doing for years with lime water.

'Reef Chemistry Calculator FV'

Randy Holmes-Farley · May 11, 2015

So taht's probably soemthing like 0.5 dKH per day, but the demand willd rop as the alk drops.

not sure why you saw no demand for a few days, but I wouldn't worry about it. It may be partly random variation in the testing.

I'd really only worry if you kept dosing the same as always and the alk continually climbed, and you had to keep backing off on the dose. That would be a clearer sign that calcification was slowing more and more.

Elevated phosphate might slow calcification, as might other stressors, such as nitrate, temperature or lighting changes, etc.

DFW · May 11, 2015

Randy Holmes-Farley said:
So taht's probably soemthing like 0.5 dKH per day, but the demand willd rop as the alk drops.

not sure why you saw no demand for a few days, but I wouldn't worry about it. It may be partly random variation in the testing.

I'd really only worry if you kept dosing the same as always and the alk continually climbed, and you had to keep backing off on the dose. That would be a clearer sign that calcification was slowing more and more.

Elevated phosphate might slow calcification, as might other stressors, such as nitrate, temperature or lighting changes, etc.

Thanks! There is no algae problems, so I don't think phosphate, or nitrates are elevated. I have been trying an experiment where I just run the royal blue LEDs on the weekends. But this period of little alk use was during the week. I have always seen less use on these weekends, and even the first day - Monday - that the t5s are back on have sometimes shown less use as well. Magnesium is elevated to around 1900 to deal with bryopsis.