Two part dosing

davemercier

New member
Hello fellow Saltwater lovers! I am hoping to get some advice on starting up two part dosing in my reef aquarium. I have a 72 bowfront with 100 lbs of oolitic sand, about 120 lbs of liverock, a skimmer, sump set up refugium style with chaeto and mangroves. My PH is always 7.8 out of my RODI system. I maintain my water temperature at 80 degrees. I have plenty of flow, good lighting, and am just now at one year running the tank. It's a mixed reef tank with a good variety of corals with about 35% of them being SPS. So far, without dosing and just bi weekly 25% water changes, my magnesium, alkalinity, and calcium levels are in the ranges that most folks seem to agree are good for coral growth. I expect this is due to my corals still being smaller or just frags begining to grow. I went ahead and bought two dosing pumps and the chemicals to do the two part method, but i'm wondering if i start dosing, if i'll be adding too much of something like say calcium which then will precipitate out of the water or who knows what all may happen? I've seen it advised, to start with the agnesium first, but i'm not sure of anything, and i want to get off on the right foot here, and not damage everything i've spent this past year trying to make this into something beautiful. I'm trying to figure out if i need to wait on the dosing until i maybe see my levels of calcium, Mag, or alkalinity drop, i would assume from the corals depleting one or more of them as they grow, which they are doing. Any and all help here from those willing will me most welcome. I will be very grateful, as i know one thing for sure, and that is how truly priceless sage advice is from good people like i read about in these forums. Thanks so very much!
 

Psirex

New member
What are your current levels at?

Mg
Calc
DKH

How often do you test?
what are the levels at BEFORE you do a water change?
What are they at AFTER?

Actual numbers would be better to go by.
 

downbeach

New member
I would probably do fewer water changes, twice a week @ 25% is really a lot of salt mix. I think twice a month would be good.
Your testing, and what you test with will be important here. So, a good calibrated refractometer is important. A good kit for measuring your Ca, Mg and Alk, Salifert or the new Red Sea Pro kits would be good choices.
First thing would be to get your parameters where they need to be; say Ca @ 420, Alk @ 8 dKH, and Mg @ 1350. Once they are at a level you select, start to measure how much your system uses over a period of time. This will give you your current base line to determine how much to dose depending on which two part you are using.
 

davemercier

New member
I'm sorry, i thought that biweekly meant every two weeks. I change 25% of the tanks water twice a month. I tested my mag, calcium, and alkalinity three times in one day and got almost identical results each time with the mag at 1300to 1340, the calcium between 470 and 500, and the alkalinity at 8 dkh all three times. Aside from that i haven't done any testing of these three parameters as i believed the test results i got were what i have consistently at least for a while.
 

downbeach

New member
If your readings stay within those parameters, between your WC's then you aren't ready to start dosing anything yet. The levels that are contained in your salt mix is providing enough to meet your current demand. You might just start adding some kalk to your top off water (1tsp. per gallon) and that will help to maintain your levels between your WC's, and help with the pH a bit.
I would test the Ca and Alk at least weekly to see what the levels are.
 

davemercier

New member
Ok, i'll start monitoring my levels more and see if they are that good consistently for a while. Thanks very much for your help evryone!
 
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