having trouble getting baseline for two part

[wildwilly1]

i currently have a 120 peninsula tank.running reef octopus 200 elite skimmer,gfo and carbon in reactors, started dosing brs twopart. what is the best way to figure out how to set up auto doser. how much I will need to dose daily of each calc,alk and mag. I do have all the test to check levels just having trouble on how to set up amount of daily dosing for auto doser. last night calc was 450 alk was 9.0 magnesium was 1200 so I only dosed mag solution manualy. what is the best way to figure out what I will need thx

 

[redfishbluefish]

There are two ways that I'm aware of for figuring out your daily demand for alk and calc.

METHOD 1: Test alk and calc levels. Do not dose for three days. Test again and you've determined your consumption. Use a tank calculator to determine how much you need to dose daily to maintain the numbers you wish.

METHOD 2: Make an educated guess what you think your tank might need. If it where me with a 120 gallon tank, I'd pick 50 mls. Start dosing 50 mls per day and measure alk and calc levels every day. adjust up or down as needed to maintain the levels you wish. As you get a feel for the demands of your tank, you can reduce the frequency of testing. I only test about every month or so with my tank.

 

[wildwilly1]

thx a lot that's .I tested last night so I will test again Thursday night and see what I have used. then I will just divide that by 3 and that gives me my daily dose per day correct. also calcium should be dosed throughout day and then alk dosed at night is that right . what about magnesium when should I dose it thx

 

[redfishbluefish]

I know some dose alk at night to help keep pH up when lights are out. I'm not convinced it's critical or has a positive impact. I think what's more important is keeping as stable an alk level as you can. Accordingly, in my opinion, dosing throughout the day and night is better. The only thing you'll want to do is either separate the dosing of alk and calc by about five minutes or dose them at the same time, but as far apart as you can get the two dosing points (say one in your sump, the other in the DT). Alk and Calc dosed in close proximity at the same time will cause for immediate precipitation of calcium carbonate.

As far as MAG, the demand is fairly low and with some salts and frequent water changes, you might not need to dose, or only dose infrequently. I dose manually and can't even tell you the last time I dosed....maybe a year ago.

 

[wildwilly1]

thx so I will should prob set up doser to do calc and alk throughout a 24hr period about 30 mins apart that should work right say dose calc at 12 alk at 12:30 then calc at 1:00 and so on right?

 

[redfishbluefish]

Sounds like a great plan!

 

[Downbeach]

I like to start by making sure my SG is accurate, since this is where you'll be adding much of those elements to begin with, and keeping a regular WC schedule of both volume and frequency will help offset any squewing that may occur. I preferred a SG of 1.026 and measured with a properly calibrated refractometer using a 35 ppt solution. With that established, use whatever two part you need, individually or collectivley to get to the numbers you like, i.e. Ca @ 420ppm, Alk @ 8dKH, Mg @ 1300, etc. I would then measure and record your readings for a few days to a week to determine how much you're using. Use this calculator, fill in the blanks for your system, select Randy's recipe #1(soda ash) from the drop down menu's to get your dosage. Divide that by the number of days you tested/recorded to get your daily dose. Then, as Paul said, using your timers/controller to spread the dosing out over the day.

 

[wildwilly1]

my sg is 1.025 steady waterchanges every sunday 10% . I have my system set up pretty sweet for water changes in the back of my cabinet I have two 28 gallon containers top holds rodi plumbed to rodi filters with float switch with automatic shutoff so stays full . bottom container is for mixing saltwater. I have a pump in my sump that is plumbed to outside of house with ball valves to open and close. saltwter mixing tank is also plumbed to sump.so for a waterchange I open valve pump out old saltwater to outside home . turn off then I open valve from mixing container then pump new saltwater in exact same amount each week approx. 15 gallons . takes about 10 minutes very easy. set it up so I could do this very easy with no lifting or rolling trash can around works great . I have a digital marine salinity meter also so sg is easy to test also. just got to dial in my 2part dosing . thx

 

[Randy Holmes-Farley Verified Community Expert]

thx a lot that's .I tested last night so I will test again Thursday night and see what I have used. then I will just divide that by 3 and that gives me my daily dose per day correct. also calcium should be dosed throughout day and then alk dosed at night is that right . what about magnesium when should I dose it thx

Not exactly, but that number will give a starting dose you need. It will likely need tweaking because the demand was changing as the alkalinity declined through those 3 days.

For example, it takes substantially more calcium and alkalinity to maintain 8 dKH than 6 dKH.

FWIW, there are many control freak reefers who tweak calcium and alkalinity independently, but equal parts dosing based on the alkalinity demand is almost always adequate and appropriate.

 

[wildwilly1]

I guess I need this dumbied down for me haha randy . so should I just start with 50 ml a day each cal,alk andmag and after 3 days test and adjust as needed

 

[Randy Holmes-Farley Verified Community Expert]

The magnesium amount is much lower than the other two.

Take your measurement for the alk decline and start dosing calcium and alk based on the calculator to get a baseline going. Then tweak both up and down together to get alk where you want it.

Only adjust calcium independently if you feel strongly that it is already higher than you want it to be. If it is lower, make a one time manual addition to correct it.

Magnesium is dosed at about 1/6th of the alk and calcium volume, assuming you are using the equivalent of my Recipe #1, which is what BRS uses. If you are using something else the nag ratio to alk may be different.

 

[wildwilly1]

ok got you my calc and alk test fine yesterday mag was low so I dosed it according to brs calc. so I should test again Thursday see what tank has used divide by 3 days and start dosing that amount daily right