Alk consumption too high?

[BlueDevil]

Hello. I recently set up a new 125 gallon tank (140 total water volume). The tank is about 2 months old now. To get my dosing correct for the dosers, I have left them off and have been manually checking daily levels until I can figure out what to set the dosers at. I am a little surprised/concerned at how much alk is being consumed by my tank. As far as coral load is concerned, I have a very light load. I only have four 1" sized SPS frags, a torch with four heads, three small acans, a scoly and some small zoa colonies. I also have a 4" maxima clam. I am using Randy's Recipe 1 for alk and ca.

I thought I had the daily drop in alk figured out at 0.7dkh but after turning my dosers on at that level, dosing 70ml each per day, my alk dropped to 7.5dkh within the first 24 hrs. I am targetting 8.0 and 42 for alk and ca. At this rate, it appears that I would need in excess of 100ml per day to account for 1dkh or greater in alk consumption, which seems rather high for the coral load in my tank. I started with dry rock so there is no coralline as yet that might explain high alk consumption.

All this while, ca doesn't seem to be dropping at the same rate.

Is it normal for my tank to be consuming this much alk? I have sifted my fingers through the sand and do not see any clumps resulting from potential precipitation, not do I see any residue on pumps, powerheads etc...

I thought I might get some opinions before I continue bumping up my dosing. Thank you!

Edit: I maintain Mg at 1350. Using Tropic Marin Pro salt for changes and doing ~15 gal changes every other week.

 

[Randy Holmes-Farley]

Rising nitrate (are you measuring?) will deplete alkalinity, as will calcium carbonate precipitation.

What exactly are you dosing?

 

[BlueDevil]

Rising nitrate (are you measuring?) will deplete alkalinity, as will calcium carbonate precipitation.

What exactly are you dosing?

Yes, I am measuring all the parameters at least weekly, other than alk and ca which I measure daily. My nitrates are typically undetected, so I dose (LoudWolf) sodium nitrate solution to try to maintain them at 1. PO4 on the last test was 0.01. I do run a carbon/GFO reactor if that matters. I also dose monthly correction doses for trace elements including boron, barium, nickel, strontium, potassium, fluoride and daily drops of iodine.

For the alk and ca I use baking soda (recipe 1) and BRS calcium chloride (also recipe 1)

 

[Randy Holmes-Farley]

Does the sand seem to be clumping/hardening?

Any apparent excessive precipitation on pumps or heaters?

 

[BlueDevil]

Does the sand seem to be clumping/hardening?

Any apparent excessive precipitation on pumps or heaters?

Nope. I ran my fingers through the entire sand bed and could not find any clumps. All the equipment is also free of precipitation. Everything is new in the tank so it is very easy to spot any areas of precipitation. That is what has been me puzzled!

 

[Randy Holmes-Farley]

Nope. I ran my fingers through the entire sand bed and could not find any clumps. All the equipment is also free of precipitation. Everything is new in the tank so it is very easy to spot any areas of precipitation. That is what has been me puzzled!

It's not that high, so I'd just keep on unless and until it appears there is an issue.

 

[BlueDevil]

It's not that high, so I'd just keep on unless and until it appears there is an issue.

Will do. Guess I'll keep an eye on the precipitation and until I don't see any will gradually raise the daily dosage levels until I get to where I need to be. Many thanks, Randy!