Dosing Potassium Nitrate vs Calcium Nitrate
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Randy Holmes-Farley
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SauceyReef
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On another more recent thread I made you were telling me Calcium Nitrate would help decrease rising phosphate levels. Could it just be your opinion changed to this over the course of 5 years?
Sorry to dig this thread back up it just seems pretty relevant still. I am currently using Calcium Nitrate, and wondering if a blend would be more helpful as my last ICP test came a little high on Calcium, and a little low on Potassium. Would adding Potassium Nitrate help lower the calcium, and increase potassium in my tank? I know what sounds silly, but I guess Potassium Nitrate is different than Potassium.
Randy Holmes-Farley
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Dosing nitrate can accelerate the uptake of phosphAte, but Only if nitrate is very low to start and is limiting the growth of something, such as a coral or macroalgae.
SauceyReef
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Got it! That is the case with my tank. Very low nitrate, very high phosphate, so you reccomended dosing Calcium Nitrate. Can dosing calcium nitrate in turn increase calcium levels? Same with potassium nitrate, and potassium? I know this may sound like a dumb question, but chemistry is always proving to myself I know nothing about it lol.
Randy Holmes-Farley
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Calcium nitrate dosing will slowly supplement calcium and alk in a balanced fashion, such as happens with kalkwasser or All for Reef. The calcium rise is about 1/3 of the nitrate added.
SauceyReef
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I use all for reef, and I think with the combination of all for reef and calcium nitrate I am seeing elevated levels of calcium. With a slightly deficiency in potassium which is not in All for Reef I think it will be beneficial to switch to potassium Nitrate, right? Will help level things out.
Randy Holmes-Farley
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If potassium is deficient, it is fine to dose it. Just bear in mind that it adds 0.6 ppm of potassium for each 1 ppm of nitrate, so if you add 5 ppm of nitrate a day for a month, potassium will rise by nearly 100 ppm (a 25% increase).
SauceyReef
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Bringing this thread back. 2024 and I am still curious which Nitrate is best to dose. Last I asked I was recommended dosing calcium nitrate, and against potassium nitrate. Thing is I am having to dose a lot lately to keep up with stable nutrient levels, and I am worried about my calcium creping up (it occasionally happens).
Wondering if a mix would be best for me in this situation. What do ya'll think? Regardless I think this is a great topic to continue discussing.
Wondering if a mix would be best for me in this situation. What do ya'll think? Regardless I think this is a great topic to continue discussing.
Randy Holmes-Farley
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Potassium nitrate is always a poor choice unless you are closely monitoring potassium. If you add 3 ppm of nitrate a day for a month, you’d add 59 ppm of nitrate. Few reefs, if any, consume that much potassium.
My current best recommendation for dosing N is ammonium bicarbonate, but ammonium chloride, calcium nitrate and sodium nitrate are also suitable.
SauceyReef
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Do you think it would be valuable for me to try all three in this situation?
I am reading your thread about ammonium bicarbonate you started in 2023 - great stuff as usual! https://www.reef2reef.com/threads/diy-ammonia-dosing-for-low-nitrate-systems.987087/
Randy Holmes-Farley
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Trying different nitrate solutions is unnecessary since we know the effect on the other ions. Ammonia vs nitrate is a useful tank observation comparison.
SauceyReef
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To refine my question - in my nanos could dosing Calcium Nitrate daily cause excess Calcium buildup even with weekly water changes? If the answer is yes; would it not be wise to use Calcium Nitrate, Sodium Nitrate, and Ammonia bicarbonate altogether to reduce the effect of excess calcium.
Randy Holmes-Farley
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Calcium nitrate is a balanced alk and calcium addition method. If demand is very low, alk will rise before calcium is any concern. Alk comes from consuming nitrate in any dosed form.
I dose potassium nitrate as I have a very large mangrove in my sump and it does seem to use the excess potassium. I perform monthly ICP tests and potassium is in line so I havn't seen the need to switch to calcium nitrate. I have always run a lot of macro algae in my tanks and very few fish so have always dosed it. In my new build where I’m still deciding on a refugium I would probably go with calcium nitrate if I need nitrate dosing. I actually feel the only reason I’m dosing it in my current system is because of the mangrove so removing nitrates will probably be more of the goal in my new system which will be fish heavy.
