Alkalinity will not balance

[wicz101]

So I feel like I may be missing something in the 2 part dosing process. I have recently been working on setting up 2 part dosing with a Jabeo automatic doser. I started the process of getting ALK, Ca and Mg up into the top parts of the safe ranges.
Alk- 10.5(salifert)
Ca-455 (redsea)
Mg-1400 (redsea)

I then waited 7 days and retested to see the drop, So I could figure out how much it used of each in a week, then I would know how much I needed to replace per day. The results are:

Alk- 6.4 (salifert)
Ca- 445 (redsea)
Mg- 1400(redsea)

I thought the drop was pretty high for the alk but I tested multiple times on both the pre and post, to get an average. Next over the course of a weekend I dosed the tank up to alk 8.1 and ran the doser at the number I calculated for the weekly drop, of course being afraid of overdosing the alk, I dose on the low end.

Fast forward 2 day and I retest and the alk jumps up to 10.5. I then cut my alk dosing numbers in half and retest the 24hrs later and I get 8.4.

Any thought on what is go on, thought I had a good understanding of this process and all the test kit are new/doser is calibrated/ no water changes. Am I really having that large of a drop in alk in a 24hr window in a light/very medium stocked reef tank?????

 

[thegrun]

While in a heavily stocked hard coral tank or one with strong coraline algae growth a 1.5dKh drop per day in alkalinity is not unusual, a 2.1 drop in a lightly stocked tank does seem very high. Are you adding the calcium and alkalinity at the same time, if so I would dose at separate times to limit the likely precipitation. I dose 24 tames a day, alkalinity on the hour and calcium on the half hour. Also it is important that the additives are dosed into a high water flow area or you will get calcium precipitation.

 

[hkgar]

Did you do any water changes during thsi period? The amount of Ca and Alk in the change water and the amount of change, will influence the levels.

 

[wicz101]

While in a heavily stocked hard coral tank or one with strong coraline algae growth a 1.5dKh drop per day in alkalinity is not unusual, a 2.1 drop in a lightly stocked tank does seem very high. Are you adding the calcium and alkalinity at the same time, if so I would dose at separate times to limit the likely precipitation. I dose 24 tames a day, alkalinity on the hour and calcium on the half hour. Also it is important that the additives are dosed into a high water flow area or you will get calcium precipitation.

I sperate my dosing the same way. I do have strong coralline algae growth. I have a basement sump w/ sperate rock and refuge tanks that both drain in my return. I dose into the refuge tank w/ powered for circulation as it is the longs distance of travel back to the DT.

 

[wicz101]

Did you do any water changes during thsi period? The amount of Ca and Alk in the change water and the amount of change, will influence the levels.

Nope

 

[thegrun]

I would just keep searching for the correct dosage, making slight adjustments each week until you get it dialed in. Some of the swings may be attributed simply to the inaccuracies of our test kits; try to be very consistent in your water quantity measurements during testing. It usually takes me a couple of months to get the dosing 100% dialed in and even then as coral growth changes slight adjustments are still necessary on occasion. Look for any signs of overdosing with will show up in either calcium precipitation on your glass, excessive build up on your impellers or sand clumping.

 

[wicz101]

figures crossed, but it seems that tank and dosing have started to balance out. For a little short of 2 week the are steadily at:

Alk-8.7
Ca-415
Mg-1400

as always patience, patience and more patience.

 

[thegrun]

Another thing to consider is that dosing pumps rarely dose the exact amount they are rated for and variances from one pump to another often lead to the necessity to adjust the dosing duration.