Need help from experienced 2 part users

Okay... So I started using 2 part a few weeks ago to maintain my Ca, Alk and Mg. I am confused by the results thus far

Once I had my Ca, Alk and Mg parameters where I wanted them (440, 9 and 1400 respectively) I started dosing equal amounts of Ca and Alk and a comparitively small dose of Mg each day (35 ml Ca, 35 ml Alk and 5 ml Mg) on a 65g tank. I tested all three parameters every few days expecting the levels to more or less remain constant (or close) relative to one another. This is not what occured however...

Alk & pH (biggest problem areas )

• Within a couple of days, Alk dropped rather quickly from 9 to 6-7 range and pH has dropped from a very stable 8.2-8.3 to a range between 7.7-8.0
• I tried dosing at this level after lights-out. More or less the same results.
• After 7-10 days of this, I decided to increase the Alk dose to 37.5 ml/day and saw a slight improvement - but only slight.
• I tried splitting this dose - 1/2 at noon and the other 1/2 at midnight. Again, more or less the same results. Maybe a bit better.
• A few days later - I decided to increase the Alk dose again to 40 ml/day, splitting the dose - 1/2 at noon and the other 1/2 at midnight. Things improved more significantly. Alk is now 8-9 and pH is 7.9-8.1 range

Ca

• Ca has gone the opposite direction
• Started dosing 35 ml/day. Tests revealed slowly increasing levels from 440 to 460 within about 7 days
• 7 to 10 days later... Ca increased from 460 to 480. I reduced the Ca dose to 32.5 ml/day
• Another 3 to 4 days later - Ca has increased to 520 (too high! )
• I am going to forgo dosing for a week so that things can drop back down to the 420-440 range and then resume daily dosing at 25 ml/day

Mg

• Started at 1400. Dosing 5 ml/day
• Dropped to 1300 within 10 days. I manually brought it back up to 1400 again. increased daily dose to 7ml/day to try to maintain this level.
• Increased to 1480 within another 10 days.
• I guess I will split the difference now and dose 6 ml/day. Hard to believe that 1 ml would make that much of a difference...

I am confused... Isn't the whole idea of 2 part to dose the Ca and Alk at the same levels?? Is it normal to be dosing vastly different amounts like this?

One thing I should point out that I suspect is impacting the Alk & pH levels... I use a sulfur denitrator which contains sulfur (to remove nitrate - byproduct is acid) plus aragonite (to help neutralize the acid). The resultant effluent has a pH of around 7.3 - so I aerate it with an airstone before returning it to the sump. The aeration process moves the effluent's pH from 7.3 to around 7.6.

Am I doing something wrong with this whole 2 part business?

Any advise would be appreciated.


Z

 

ZZipper
So here is what I have learned.

Adding CA and MG needs to ONLY be done according to you livestock consumption. Do you have a tank full of Corals that are consuming CA and MG ? Once you reached you target, I suspect you should have stopped and checked after a week or two to see what happened. Unless you are really stocked, these two wont drop that quick.

Now the ALK is a different story. This is where it is unstable. For me, when I got to 10, if I add 120ml every wed and sat, I can keep it pretty stable. But if I dont it will drop to 8.

The trick to all of these is finding your zones. Hold off on the CA and MG but keep testing and keep an eye on it. Find out what the correct additions of ALK is, use the calculator on line at BRS dont just guess. DONT forget to know your actual water colume not just your tank size.



Cheers

 

You will need to use a few high doses of alk to get the alk "balanced" with the calcium. High calcium will push low alk even lower. I think this is what you are experiencing. I would stop dosing calcium for a few days. Then take on the alk head on. Plug in your alk paramaterers and your desired into the "reef supplements" calculator. It will tell you how much to dose, dose half of that the first day. The second day take another reading, if its exactly at the halfway point between what your alk was the day before and your desired alk, dose again with the same amount. If not plug in your numbers to the calculator again and dose whatever amount it tells you. The next day do another test and see where you stand with both alk and calcium. My reccomendation for you is to either raise your desired alk to 10 or 11, or drop your desired calcium to 420. 440 and 9 is not a prefect balance. I think the ratio is 40ppm to 1dkh, don't quote me there though. Once you get them perfect again, if alk starts falling off again I would start looking towards your sulfur denitrator again.
This is a good article explaining some things that can make a balanced supplementation scheme unbalanced. When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com

 

My Two Part from BRS says to use 1 gallon of Alk and Ca before dosing the Mg (at which point I should dose 20oz Mg).

Which is different from your daily Mg dosing...

 

I started using the exact same ratio (1 gallon of Alk and Ca to 20oz Mg) - I just calculated it down to a daily dose instead of waiting to exhaust the entire 1 gallon of Alk and Ca. I am glad I've taken this approach... Based on what I am experiencing, I will be running out of Alk before I run out of Ca... Which would have confused the heck outta me. Should I dose when the Alk runs out? Or when the Ca runs out?

Z

 

Awesome article!
Thanks!

Z

 

My directions also say to dose mag at the end..however I think that is too much mag to dump in at once. I dose my mag in thirds....my mag is staying well at 1200 or so...

 

I found the same thing. Dosing equal parts was making my calcium go too high (500 ppm) and my Alkalinity was staying too low. I pretty much have stopped dosing calcium for now. I use coralife salt that has a calcium level of about 520 ppm or so. Just doing water changes every two weeks is keeping my calcium in the right range.