I recently attempted to clean my sand bed and found the upper 1/2" or so has solidified (calcified?). I checked my levels today and found my Alk reading 16 (really high) and my Cal level to be 150. 150 seems to be waylow although I used two different text kits and found similar values. It's been a crazy busy summer so I'm not sure how long this has been building up to these levels. The tank looks fine, some of the corals are loosing some color but I believe that is more due to low Nitrate levels (3 ppm) and PO4 (1 ppb). I've been dosing BRS two part and Mg (current level is 1400 ppm). The only other thing I've noticed recently is my Ph is in the 8.5 range. I'm going to stop the part 1 dosing, and do a pretty major water change, my question would be should I increase the Calcium dosing or would that just increase the precipitation issue?
High Alk, odd low Calcium levels
- Thread starter reefruss
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chipmunkofdoom2
Always Making Something
+1. Ca below 150 ppm smells a lot like testing error. So does Alk = 16 dKh. What test kits do you use? Are they expired?
I used both salifert and red sea. The salifert is on the older side but the red sea was purchased recently. They gave similar readings. I find the calcification of my sand bed telling. I'm not sure why it happened or if it's a function of too high of Alk and too much Calcium. My calcium reading were higher than normal (>500) in the past but my Alk was always in the 9 range. I've stopped all part 1 dosing and I'm mixing fresh water to do a significant water change. Other than that I don't know of a way to change things significantly.
I tested my freshly mixed water and I got fairly normal results (Alk 8.8, Cal 375) so it's safe to assume it's not the test kit (or the tester). I did a 20% water change today and my values went to Alk 14.2 and Cal 175. Still a ways off normal but closer. I did notice that my zoas didn't like the major change, but I suspect they'll be fine by tomorrow. I can understand how my Alk got so high but I'm still perplexed how the Calcium levels got so low. I don't have a lot of stony corals to consume that much calcium so I have to believe it was lowered by precipitation. I would like to know the chemical means for this to occur.
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When Alk increases, so does CA consumption, whether it be by your corals or precipitation. In your case, the CA precipitated onto your sand bed. Are you sure your Magnesium is at 1400? Usually, CA precipitation increases when the magnesium is low. Magnesium helps prevent precipitation. I try to keep my magnesium level around 1450. But 1400 is good. You need to balance your parameters and adjust how much you are dosing. I try to keep my Alk at 8 to 8.5, Calcium around 400, and Magnesium around 1450. I have a 55 gallon mixed reef and dose 90ml/day of each (Alk and CA........BRS 2 part solution). How much are you dosing of each?
Bulk Reef Supply’s website has some good videos on how to properly dose. Their dosing calculator is VERY helpful
Bulk Reef Supply’s website has some good videos on how to properly dose. Their dosing calculator is VERY helpful
The magnesium level was measured at the same time as the high Alk and low Ca levels were detected. I currently am not dosing part 1 until the Alk levels are back in a normal range, I was dosing 48 ml per day. I am also currently dosing 48 ml of part 2, Ca, a day and I have a larger system than you, I'll bump up the Ca dosing for awhile until things are back in a a normal range. I also dose mg but not very much, I honestly don't remember how much at this point. Thanks for the info on the BRS calculator, I'll check it out.
