Erasmus_Crowley
New member
I was hoping to consult the minds here on the forums, as chemistry is not my forte, about an idea I've been playing with.
I have a very lush refugium with chaeto and caulerpa. Lately, the growth of my chaeto has stalled, and my caulerpa started turning white. I tried dosing iron, with no visible improvement. I have a nitrate test kit, but no PO4 kit yet. My nitrates have been at a solid zero for a long time now (months). I have a low bioload and I feed sparingly. One cube of food lasts me a week or more, for example. I'm convinced that I still have some PO4 issues in my rocks and sand despite solving the nitrate issue because I recently fought (and defeated) a red slime problem, and now I'm fighting a wiry turf algae that is really hard to get off my rocks.
A while ago, after reading some interesting threads here, I decided to wait for the display lights to go out and dose some potassium nitrate into my sump, in the hopes that my fuge algae will then start to soak up the remaining phosphates. That seems to be a success. I dose a few ppm of nitrate at night, and it's back to zero in the morning. It feels like I can see my caulerpa growing as I watch it, it's sprouting new shoots and leaves so fast.
However, I have a few lingering concerns in my mind.
For one, I believe that potassium gets consumed by macroalgae at a much slower rate than nitrate. So over time, I'm afraid that my potassium levels are going to creep upwards. Which means I'll have to get a potassium test kit, and do water changes to bring it back down, which is annoying, as I generally don't do water changes at all.
The other issue is that as nitrates are consumed, they might slowly increase the alkalinity of the water and throw off the alk/calc balance. Calcium chloride would fix that, but in turn it would increase the chloride in the water, throwing off the sodium/chloride balance.
So I started thinking about calcium nitrate instead of potassium nitrate for the nitrate source, because the consumed nitrate would become alkalinity for the coral and the calcium would balance it out, essentially making it similar to kalkwasser, with the added step of having to be processed a bit by the macroalgae.
Would any chemistry gurus be able to tell me if there is a certain ratio of potassium nitrate to calcium nitrate that would match the needs of the macroalgae for potassium per nitrate, while also balancing the calcium and (nitrate derived) alkalinity to match kalkwasser?
If there are any other issues that I'm missing, I'd love to hear about those as well.
I'll just preemptively say, I do realize that Phosguard or and/or GFO would be easier than all this, but I really enjoy my refugium, so I would prefer this route.
Thanks for reading all that. Sorry for the wall of text.
I have a very lush refugium with chaeto and caulerpa. Lately, the growth of my chaeto has stalled, and my caulerpa started turning white. I tried dosing iron, with no visible improvement. I have a nitrate test kit, but no PO4 kit yet. My nitrates have been at a solid zero for a long time now (months). I have a low bioload and I feed sparingly. One cube of food lasts me a week or more, for example. I'm convinced that I still have some PO4 issues in my rocks and sand despite solving the nitrate issue because I recently fought (and defeated) a red slime problem, and now I'm fighting a wiry turf algae that is really hard to get off my rocks.
A while ago, after reading some interesting threads here, I decided to wait for the display lights to go out and dose some potassium nitrate into my sump, in the hopes that my fuge algae will then start to soak up the remaining phosphates. That seems to be a success. I dose a few ppm of nitrate at night, and it's back to zero in the morning. It feels like I can see my caulerpa growing as I watch it, it's sprouting new shoots and leaves so fast.
However, I have a few lingering concerns in my mind.
For one, I believe that potassium gets consumed by macroalgae at a much slower rate than nitrate. So over time, I'm afraid that my potassium levels are going to creep upwards. Which means I'll have to get a potassium test kit, and do water changes to bring it back down, which is annoying, as I generally don't do water changes at all.
The other issue is that as nitrates are consumed, they might slowly increase the alkalinity of the water and throw off the alk/calc balance. Calcium chloride would fix that, but in turn it would increase the chloride in the water, throwing off the sodium/chloride balance.
So I started thinking about calcium nitrate instead of potassium nitrate for the nitrate source, because the consumed nitrate would become alkalinity for the coral and the calcium would balance it out, essentially making it similar to kalkwasser, with the added step of having to be processed a bit by the macroalgae.
Would any chemistry gurus be able to tell me if there is a certain ratio of potassium nitrate to calcium nitrate that would match the needs of the macroalgae for potassium per nitrate, while also balancing the calcium and (nitrate derived) alkalinity to match kalkwasser?
If there are any other issues that I'm missing, I'd love to hear about those as well.
I'll just preemptively say, I do realize that Phosguard or and/or GFO would be easier than all this, but I really enjoy my refugium, so I would prefer this route.
Thanks for reading all that. Sorry for the wall of text.
