alk stability question

[CindyKz]

Hello,

I began supplementing my alk using Reef Fusion 2 and a dosing pump about a month ago. Everything was fine initially, I started low and gradually increased until I got to my goal of stable around 8.5 at 6 ml/day. I was testing alk most nights with spot checks of Ca and Mg. I use Reef Crystals which is higher in Ca it seems, my Ca does drop but not enough to need to supplement it yet.

I noticed that about once a week, usually later in the week, my alk would take this precipitous drop and I'll have to hand - dose along with the RF2 delivered by my pump. This doesn't happen every single week. I'll hand-dose, one night maybe 2, then it will be time for a water change. Then the cycle may or may not repeat the following week. Below is typical. Where you see the alk jump up are nights that I corrected it by hand in addition to letting the pump continue. During this particular week I increased it to 8 ml/day also,which is where it remains.

26 Mar (following a 10% water change) 78.2 1.026 NO3 5 alk 8.624 Mg 1440 Ca 460
27 Mar alk 8.512
29 Mar alk 7.952
30 Mar alk 8.736
31 Mar alk 8.176
1Apr (0645) alk 8.624
1Apr (evening, after 10% water change) 77.8 1.025 No3 2.5 Alk 9.5 Mg 1520 Ca 470

What would cause this? How do I address it? I am going on vacation next week, my daughter will be tank sitting and I can't have her testing and dosing. Not to mention I'm anxious to get this pump dialed in once and for all.

Forgot to say, this is a 75 gal mixed reef with softies, LPS and just a few beginner SPS. 4 fish. The usual inverts. It has been up since September. Everything seems to be doing very well, I can actually see growth on many of the corals which I'm pretty excited about.

TIA for any helpful input,

Cindy

 

[Randy Holmes-Farley Verified Community Expert]

It is not normal for a reef tank to change the alk demand day to day unless something happens that impacts it. Most people find it can be matched with dosing pumps so that fluctuations are not significant.

I have to say, I can't really see sudden jumps from the data you give.

Reasons for jumps might include testing error, which is a lot more common than many folks think.

The water change with reef crystals will also give a small alk boost.

 

[CindyKz]

It is not normal for a reef tank to change the alk demand day to day unless something happens that impacts it. Most people find it can be matched with dosing pumps so that fluctuations are not significant.

I have to say, I can't really see sudden jumps from the data you give.

Reasons for jumps might include testing error, which is a lot more common than many folks think.

The water change with reef crystals will also give a small alk boost.

Hi Randy, thank you for the reply. My concern is actually about occasional drops, not jumps, but I am sure your comment regarding testing error applies to both. I did double check in all cases. Do you think the above alk levels are acceptable with a dosing pump in use? Remember I hand dosed on 3/29 and 3/31. Your comment about not seeing any jumps makes me wonder if I'm overthinking things, and maybe testing too much when I should be watching trends.

Your help is appreciated, thank you!!

 

[CindyKz]

It is not normal for a reef tank to change the alk demand day to day unless something happens that impacts it. Most people find it can be matched with dosing pumps so that fluctuations are not significant.

I have to say, I can't really see sudden jumps from the data you give.

Reasons for jumps might include testing error, which is a lot more common than many folks think.

The water change with reef crystals will also give a small alk boost.

Hi Randy, thank you for the reply. My concern is actually about occasional drops, not jumps, but I am sure your comment regarding testing error applies to both. I did double check in all cases. Do you think the above alk levels are acceptable with a dosing pump in use? Remember I hand dosed on 3/29 and 3/31. Your comment about not seeing any jumps makes me wonder if I'm overthinking things, and maybe testing too much when I should be watching trends.

Your help is appreciated, thank you!!

 

[CindyKz]

It is not normal for a reef tank to change the alk demand day to day unless something happens that impacts it. Most people find it can be matched with dosing pumps so that fluctuations are not significant.

I have to say, I can't really see sudden jumps from the data you give.

Reasons for jumps might include testing error, which is a lot more common than many folks think.

The water change with reef crystals will also give a small alk boost.

Hi Randy, thank you for the reply. My concern is actually about occasional drops, not jumps, but I am sure your comment regarding testing error applies to both. I did double check in all cases. Do you think the above alk levels are acceptable with a dosing pump in use? Remember I hand dosed on 3/29 and 3/31. Your comment about not seeing any jumps makes me wonder if I'm overthinking things, and maybe testing too much when I should be watching trends.

Your help is appreciated, thank you!!