Two-Part Precipitation No Matter What I Try

[Trenton Henderson]

Alright, I’ve got a bit of background to cover, so hang in there! I just want to provide everything I can!

Current Tank Parameters:
Salinity: 1.025 sg
Ca: 410 ppm
Alk: 7.85
Mg: 1350 ppm
pH: 8.2-8.3
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: near 0 ppm (have an API test kit)
Phosphate: near 0 ppm (have an API test kit)

For reference, the tank was started up and began its cycle in late September to early October 2022. The tank has 2 small oscillaris clownfish and a royal gramma with several hermit crabs, snails, and a skunk cleaner shrimp. The royal gramma was the latest addition (1 week ago). Most importantly, I have no coral, just a new bloom of coralline algae!

This is my third saltwater tank, the first one, however, that I intended to make a reef tank. Because of this, I began testing calcium, alkalinity, and magnesium to get a handle on things. I began to notice, as I anticipated, that the cycle was producing acids that were diminishing my alkalinity. I went and grabbed a gallon mix of BRS sodium bicarbonate to help raise it. I got it on par and noted that I was losing about 0.5 dKH per day. From there, I kept the dose at a constant level and it stabilized at 9 dKH (as desired).

During this time, coralline algae had begun to grow because I had dosed both purple and pink coralline algae in a bottle. This spiked my interest in testing for calcium and magnesium as well. Doing so, I found that my calcium was quite low (340-350 ppm) and so was magnesium (1275 ppm).

From here, I decided to replenish the elements with BRS two-part mixes (calcium chloride, soda ash, and magnesium mix). This was the beginning of precipitation central; at least that’s what I believe it to be, as there is no way that the amount of coralline I have growing plus acids from bacteria are depleting my alkalinity and calcium as they are.

For reference, I would like my alkalinity at 9 dKH and my calcium at 440 ppm. My levels would rose appropriately and then depleted by the next morning (when I test). It seems it precipitates over the course of the day and does so by about 1 dKH and approximately 10 ppm of calcium.

Knowing that sodium carbonate can precipitate worse than sodium bicarbonate, I switched back to sodium bicarbonate, but I still seem to get this precipitation effect. I did take Randy’s advice and stop dosing for a few days and let it fall then tried to bring it back up with no avail.

Also, within this span, I tried to do a water change after doing this no dosing for a few days technique with new water (25%) at levels of Alk = 9.0 dKH, Ca = 430-440 ppm, and Mg = 1400 ppm. The next morning, I tested, and my parameters had actually further dropped (likely precipitation with the massive amount of new calcium and alkalinity).

I can’t figure out for the life of me how to get this stuff to stay up. I know overdosing can cause this issue, but I’ve tried to address it. Any suggestions for a newbie to two part? And, as an aside, how long does a new tank generally impact alkalinity? I’m sure it varies, but I wanted to know your experience!

I don’t feel like, as a person with currently no corals, parameters should drop as they have, but I would like to keep my coralline growing, so parameters where they should be is important! I have pictures of the tank, precipitation, and coralline attached!

Thanks in advance!

 

[blaxsun]

While I'm not using 2-part per say exactly, I do dose alkalinity on one doser and calcium+magnesium on the other doser. These are staggered at 2-hour intervals to keep separate. I find that if I overdose calcium I do end up with precipitate, so I tend to err on the low side with my dosing.

 

[TokenReefer]

How much coralline do you have growing?

 

[Trenton Henderson]

blaxsun, I do believe that it might be a pacing of dose situation too and have considered dosing pumps.

And TokenReefer, I thought photos uploaded with the post, but I’m attaching them here.

 

[TokenReefer]

Could it just be detritus on the pump? So you're losing one full dkh a day? Wish I knew corralline consumption rate but that seems high for what I see imo

 

[Trenton Henderson]

It could be. I don’t see much of anything on my heaters. I know coralline consumes an elevated quantity of magnesium, but not really for the other elements. Especially when the coralline is still so small.

 

[homer1475]

The pump picture is ditritus, not precip. And 1DKH a day is totally normal in a new tank growing coralline.

Unless yo have a white crust on pumps, and heaters, or sand hardening in areas(typical precipitation events) , your using the elements.

Not sure what the big mystery here is?

 

[TokenReefer]

Welp guess it's normal then. Sorry lol. Never tracked alk before I had coral fwiw

 

[Trenton Henderson]

I’ve just never tracked this stuff before and it simply seemed rather high, especially for the small quantity of coralline in there!

Thanks for the pointers!

 

[Trenton Henderson]

So here is an update:

I tested again this morning after dosing only the amount of sodium bicarbonate to bring up my alkalinity 1 dKH from 7.85 to 8.85 and no calcium. Today my alkalinity read 8.45, showing around a 0.5 dKH reduction over the course of the day, and not 1 with the addition of calcium. Calcium, on the other hand, dropped from 410 ppm to 400-405 ppm. Is that a sign of precipitation, or is that just coralline consumption?

It seems that, with no calcium chloride addition within the same day, I do not have as severe of parameter drop offs. I topped off my alkalinity back to 9 this morning. Should I add calcium later in the day in a small quantity? Perhaps dripping it in?

Thanks again everyone!

 

[Randy Holmes-Farley]

So here is an update:

I tested again this morning after dosing only the amount of sodium bicarbonate to bring up my alkalinity 1 dKH from 7.85 to 8.85 and no calcium. Today my alkalinity read 8.45, showing around a 0.5 dKH reduction over the course of the day, and not 1 with the addition of calcium. Calcium, on the other hand, dropped from 410 ppm to 400-405 ppm. Is that a sign of precipitation, or is that just coralline consumption?

It seems that, with no calcium chloride addition within the same day, I do not have as severe of parameter drop offs. I topped off my alkalinity back to 9 this morning. Should I add calcium later in the day in a small quantity? Perhaps dripping it in?

Thanks again everyone!

Normal.

The difference between calcium dosing and not on a single day is just random test error.

 

[Trenton Henderson]

Normal.

The difference between calcium dosing and not on a single day is just random test error.

So why might it be that when I dose both, I see over twice the drop in alkalinity over 24 hours? Is that a product of the quantity/rate at which I dose?

 

[Randy Holmes-Farley]

So why might it be that when I dose both, I see over twice the drop in alkalinity over 24 hours? Is that a product of the quantity/rate at which I dose?

Test error, assuming you did not dose them simultaneously and close together spatially so the concentrated clouds of supplement mixed together before they mixed in.

There's no difference in alk consumption between calcium at 400 ppm and calcium at 410 ppm.

 

[Trenton Henderson]

Test error, assuming you did not dose them simultaneously and close together spatially so the concentrated clouds of supplement mixed together before they mixed in.

There's no difference in alk consumption between calcium at 400 ppm and calcium at 410 ppm.

I dose them a good bit apart, but it seems only the alkalinity drops significantly (1 dKH) when calcium is dosed in tandem, but not when alkalinity is dosed alone. Calcium changes minimally (to test error as you say).

 

[Randy Holmes-Farley]

I dose them a good bit apart, but it seems only the alkalinity drops significantly (1 dKH) when calcium is dosed in tandem, but not when alkalinity is dosed alone. Calcium changes minimally (to test error as you say).

Calcium testing is not precise enough to reliably detect the balanced amount to 1 dKH of alkalinity, since it is only about 7 ppm, and I really do not think the correlation that you note will hold up on multiple repeated tests.

 

[Trenton Henderson]

Calcium testing is not precise enough to reliably detect the balanced amount to 1 dKH of alkalinity, since it is only about 7 ppm, and I really do not think the correlation that you note will hold up on multiple repeated tests.

So are you of the opinion that both the calcium and alkalinity differences in seeing are by testing error? I understand that for calcium, as the relative change is minimal to the entire concentration of calcium, but alkalinity being 0.5 dKH less one day and 1.0 another seems like it would be more accurate by the test. I could be wrong, and you are the professional here, so I’m just trying to ensure what I’m hearing. My ultimate question still remains (unless I’m not reading between the lines): why is it that sometimes my alkalinity drops by 0.5 and others a full 1.0 dKH? I would think this would be consistent, no?

 

[Randy Holmes-Farley]

So are you of the opinion that both the calcium and alkalinity differences in seeing are by testing error? I understand that for calcium, as the relative change is minimal to the entire concentration of calcium, but alkalinity being 0.5 dKH less one day and 1.0 another seems like it would be more accurate by the test. I could be wrong, and you are the professional here, so I’m just trying to ensure what I’m hearing. My ultimate question still remains (unless I’m not reading between the lines): why is it that sometimes my alkalinity drops by 0.5 and others a full 1.0 dKH? I would think this would be consistent, no?

Since I have read thousands of threads on two part dosing over the past 30 years (really, thousands), and I've never before heard anyone claim that the alk consumption depended on whether they happened to dose calcium the same day, coupled with the lack of any meaningful chemical mechanism for it to happen, makes me very confident that it is not something that you would observe on repeated testing.

Why exactly you observed it, I do not know, but remember that a change in alk is a combination of two tests, and if each is good to +/- 0.3 dKH (like the Hanna alk checker claims to be), then one can easily see a difference of 0.5 dKH between tests of one alk drop compared to another alk drop.

 

[Trenton Henderson]

Since I have read thousands of threads on two part dosing over the past 30 years (really, thousands), and I've never before heard anyone claim that the alk consumption depended on whether they happened to dose calcium the same day, coupled with the lack of any meaningful chemical mechanism for it to happen, makes me very confident that it is not something that you would observe on repeated testing.

Why exactly you observed it, I do not know, but remember that a change in alk is a combination of two tests, and if each is good to +/- 0.3 dKH (like the Hanna alk checker claims to be), then one can easily see a difference of 0.5 dKH between tests of one alk drop compared to another alk drop.

Okay great! This makes good sense to me! Thanks for helping me understand! I appreciate the time!