Figuring out my daily dosing requirements. Have I got this right?

[legrunt]

So I've reached a point in my tank's journey where I am starting to need to dose magnesium and calcium. Previously, I've already been dosing alkalinity and doing more and more water changes. I used to do up to 30% weekly, but I'm trying to cut that down to 10% weekly or bi-weekly, and therefore will need to supplement more.

So, here's what I'm thinking of doing.
Test for my parameters on day 1. Dose nothing for the rest of the week. Test again on day 7, check what the drops are in all three are, throw them in an online calculator to get them back to where it was on day 1, get all 3 amounts and divide by 7 for the daily dosing needs.

Anything I'm missing?

I got the brightwell additives, btw. Alkalin8.3, calcion and magnesion... Anything to keep in mind, like dosing them at least x amount of minutes/hours apart or something?

 

[andrewey]

Depending on the drop, you might want to test more frequently than once a week to get your starting daily alkalinity dose as rates of calcification will decline as the week goes on and skew your results (as the alkalinity decreases, the rate of calcification, measured here as the decrease in alkalinity, will slow). Therefore, you are more likely to underestimate your alkalinity dosing needs if the interval is long enough. For example, if your alkalinity were 7.5 and your daily consumption was 1 dkh/day, you might end the week at 6dkh and erroneously believe your daily dose should be ~0.2dkh/day. You would eventually catch that mistake the next week when you tested and need to recalculate


Additionally, you probably won't want to test your Magnesium twice during that week. The rate of consumption is very low, think a few ppm per day- you might not pick that up with your Magnesium test kit unless you extended the time frame out. Most people dose their magnesium pretty infrequently compared with alkalinity or calcium (although you could always dose daily if you were inclined). I would get a baseline measurement (e.g. 1320) and dose to the level you desire. From there, you can estimate when your Mag will drop 50-100ppm and estimate when the next time you'll have to test is. That will give you a much smoother line to base your dosing around.

Obviously, you'll want to spread out your calcium and alkalinity doses to avoid precipitation. For those that dose twice a day, it's common to dose one in the AM and one in the PM. If you are using a doser, it's still good practice to separate each dose at different hours.

 

[Nick Steele]

If your sure you need to do I’d say take measurements daily for a week or two to get a baseline going. Like above you can skew results by waiting too long.

 

[legrunt]

Good points! Thanks!

 

[legrunt]

Hi guys. So here's what happened over the course of 6 days.

The only thing i was dosing was my alkalin, on a doser. But i reduced the amount to 4ml a day.
My alk dropped from 9.7 to 7.8. i think I'm going to try to maintain it to around 8. So I'm increasing my dose to 6ml a day.

My cal went from 426 to 433. Not sure how it could have gone up, but maybe due to test kit tolerances. (Hanna 758 checker). So I'm going to assume the calcium consumption is very low.

My mag on the other hand, went from 1330 to 1290. According to http://reef.diesyst.com/chemcalc/chemcalc.html
I needed to dose 28ml to get back to 1330.
28 over 6 days results in around 5ml a day. So logically, should set a doser head for mag?

Does it seem strange to set up a doser head for alk and mag but not cal?

 

[Nick Steele]

Most supplements recommend dosing in equal portions. I would go testing error with calc since Hanna is known for that.

Also depending on what you are dosing with the calcium part with have the required magnesium in it so no need for extra dosing for magnesium would be needed depending on what you are dosing with.

I’m not familiar with Brightwell to tell you Specifics maybe someone else is.

 

[legrunt]

I tested my 3 chem parameters this morning.
Alk is still dropping. Was 7.8, now it's 7.6. i guess i need to up the dosage?

Cal was 427. Not too bad. I'll test in a few days to determine the dosing.

My mag, on the other hand... Jumped to 1500!
I ran out of my nyos test kit, so i broke out a brand new one. Nyos also, everything looks the same, but i tested 3 times to rule out human error, and all three times i had to use the full 1ml to get the colour change! The previous test kit read at 1290, so i dosed mag to get 1330 based on the calculator.

Can anyone advice?

 

[legrunt]

I tested my 3 chem parameters this morning.
Alk is still dropping. Was 7.8, now it's 7.6. i guess i need to up the dosage?

Cal was 427. Not too bad. I'll test in a few days to determine the dosing.

My mag, on the other hand... Jumped to 1500!
I ran out of my nyos test kit, so i broke out a brand new one. Nyos also, everything looks the same, but i tested 3 times to rule out human error, and all three times i had to use the full 1ml to get the colour change! The previous test kit read at 1290, so i dosed mag to get 1330 based on the calculator.

Can anyone advice?