2 Part Dosing Question

ddrueckh · Dec 29, 2015

Is it better to dose alk (2 Part Soda Ash) just at night or over the entire 24 hour period? Thanks.

redfishbluefish · Dec 29, 2015

I can only comment on what I saw with my tank when I use to manually dose (one dose a day) versus having my controller dose using pumps with small doses over the day....with both alk and calc. The manual dose tank look OK, but when I went to dosing over the day, it seems like stuff grew quicker and looked better. I think stability is the key. Dose a little over the entire day keeps parameters within a tight range. Single dose a day causes a swing up, that then comes down over the next 24 hours. JMTC.

twilliard · Dec 29, 2015

24 hours is the best imo.
As said its about stability

Zane · Dec 29, 2015

i don't know if its better or not, but I dose each part every other hour throughout the day, so the doser runs every hour, and the 3rd pump for mag runs twice a day.

zzzdiver · Dec 29, 2015

I do 16 times in 24 hrs

twilliard · Dec 29, 2015

I drip 2.5 ml an hour with the system I use

Randy Holmes-Farley · Dec 29, 2015

It is better at night from as pH perspective.

It is better during the day to most stabilize alk since some people find the most demand for alk is during the day.

Dosing 24/7 seems a reasonable compromise, but either way is probably OK.

ddrueckh · Dec 29, 2015

Thanks for all the replies. I will go with alk every hour and calcium on each half hour. For those who dose mag, is there a certain amount that can be calculated based on alk/calcium usage?

redfishbluefish · Dec 30, 2015

ddrueckh said:
........ For those who dose mag, is there a certain amount that can be calculated based on alk/calcium usage?

There are too many variables to give a definitive answer. These variables include the brand of salt your are using, the brand of two part (concentrations are not all the same from brand to brand), the frequency of water changes, the volume of water changes, and the corals and how they incorporate magnesium, and maybe more.

However, I believe you can get a ballpark number, especially if your using Randy's recipes (same as BRS), and specifically with recipe 1, in the example, for every 4 gallons or either alk or calc, use 0.64 gallons of mag. Now I believe this was calculated stoichiometrically, but should still put you in the ballpark.

Bottom line, you're going to have to test!

Now Randy, jump in here and whip me with a wet noodle if I'm way off base.

Downbeach · Dec 30, 2015

I started using kalk in my ATO (starting with 1 tsp/gal and going to 2 tsp/gal.) when it became apparent that my WC's were not enough to keep up with my growing demand. As time went on, and my needs increased I had to start doing the Alk part, which I was doing manually once a day in the evening, WC's were enough to keep up with my Ca and Mg needs at this time. In time I had to start dosing the Ca part as well, but the WC's were keeping up with the Mg use. As I needed to increase the amount to Ca and Alk I was using, it became apparent that I needed to automate the process, so I started to use dosing pumps, to include the kalk, which I scheduled to dose throughout the night. Ultimately I found it best to dose all three(Ca, Alk and kalk) over a 24 hour period. With my WC schedule(~ 15% every 2 weeks), I never had to dose Mg.

Randy Holmes-Farley · Dec 30, 2015

ddrueckh said:
Thanks for all the replies. I will go with alk every hour and calcium on each half hour. For those who dose mag, is there a certain amount that can be calculated based on alk/calcium usage?

There is, and I would use it as detailed in my recipe since it also keeps the chloride/sulfate balance correct and is not just for magnesium. Are you using the BRS two part (which is my recipe)? It is designed to keep magnesium approximately where it is when you start using it, but as folks note, in the long term mag may rise or fall since some corals use more magnesium relative to calcium than others. Water changes, however, will probably mess with magnesium ore than these differences.

I discuss the recipe here:

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-02/rhf/index.php

ddrueckh · Dec 30, 2015

I am using BRS two part. Thanks for the link and answering my questions, Randy! Thanks to all the others who offer helpful advice and suggestions as well.

Dave