Dosing Nitrate to reduce Phosphate

[coralreefdoc]

This is chemistry 101...

Apparently not ...

 

[ReefKeeper64]

Thanks for all the great feedback on this thread. Here is what I ordered:
Atlantis Hydroponics Calcium Nitrate, 5 lb

http://www.amazon.com/gp/product/B0013LQJKU/ref=osome x_ya_os_product

I'd like to make a 1 liter bottle of Calcium Nitrate solution of a strength that will raise 100 gallons of water by 1ppm for each 1ml that is dosed. For example, if I want to raise the Nitrate level of 100 gallons of water from 0ppm to 5ppm, I could just add 5ml of Calcium Nitrate solution.

How many tablespoons (or teaspoons) should I add to 1 liter of RO water to get to the proper ratio?

 

[disc1]

First of all, 100gallons. Let's call it 380 Liters. Makes the math easier.

You want 1mL to raise 380L by 1ppm. So 1mL must have 380mg of nitrate in it.

The calcium Nitrate tetrahydrate is 52.5% nitrate by weight.

So to get 380mg of nitrate you have 380 / 0.525 = 723.8mg of calcium nitrate tetrahydrate. If it is that much for 1mL, then for 1L it would be 1000x that or 723.8g.

Not sure what that runs into in volume measurements. It is probably somewhere around 2 or 3 or 4 cups. I would weigh it out.

 

[ReefKeeper64]

First of all, 100gallons. Let's call it 380 Liters. Makes the math easier.

You want 1mL to raise 380L by 1ppm. So 1mL must have 380mg of nitrate in it.

The calcium Nitrate tetrahydrate is 52.5% nitrate by weight.

So to get 380mg of nitrate you have 380 / 0.525 = 723.8mg of calcium nitrate tetrahydrate. If it is that much for 1mL, then for 1L it would be 1000x that or 723.8g.

Not sure what that runs into in volume measurements. It is probably somewhere around 2 or 3 or 4 cups. I would weigh it out.

Disc1, Thanks for figuring in this out. I'll take your advice and weigh out 723 grams and make the 1 liter of solution. I'll start dosing slow with 1ml of solution and work my way up each day. Thanks for the advice!

 

[JPMagyar]

I want to thank all the contributors to this thread as I have found it most fascinating, in particular this was the first time I had heard of the "Redfield Ratio" which in itself is most interesting,

BUT

here's my 2 cents:

If you want a beautiful reef, then this discussion is unnecessary. The most beautiful reefs to date did not dose nitrate to reduce their phosphate, and I see no point in trying to formulate such a process as it merely serves to complicate the issue. Live Rock, skimming, good lighting, and good husbandry are all that is necessary to produce a tank like mine. It's not that I don't enjoy the science and the chemistry; it's just that I want to emphasize that this is a hobby where people want to keep nice reefs and to do that the "KISS" principle is most important.


Joe :beer:

 

[ReefKeeper64]

Joe, Your tank is an inspiration to us all. How are you able to frequently feed those anthias without phosphate issues? The goal is to feed more but keep the phosphate at 0-2. I absolutely do everything you recommend already.

 

[ormet]

Live Rock, skimming, good lighting, and good husbandry are all that is necessary to produce a tank like mine.

And if we want a tank like Denadai's (i do) we can even remove the Live rock. Different strokes and all but its nice to know that one can acheive amazing results like yours with minimal fuss.

Good husbandry is a matter of definition though.

 

[arkuranel]

Yes, we have 72 gram water, 40 gram calcium, and 124 gram nitrate out of a total of 236 grams. Disc1, Thank you for correcting –you are welcome.

Anyway, now we exactly know that if we dissolve 236 grams of calciumnitrate tetrahydrate in 1 liter we would have 124 grams of nitrate. So, if we dissolve 100 grams in 1 liter than we will have 52,50 grams of nitrate ( 52,5 %).

To raise the NO3 content of 380 liters by 1 mg/l than from above solution how much we should dose?

1- So we need 1 mg/l x 380/0,525 = 723,8 mg or 0,7238 grams.
2- We have a stock solution of 1 liter with 52,50 grams of NO3 inside.
3- There: 0,7238 x 1000/52,50 = 13,78 ml.

To underline: When you like to raise your NO3 concentration by 1 mg/l of your 380 liters (100 gallon) tank, than you would dose 13,78 ml from your stock solution made with 100 grams of calciumnitrate tetrahydrate dissolved in 1 liter of RO water.

Any contribution is welcome once more.

However, once more, I would suggest starting with 1 drop to see the results to avoid something wrong…

 

[arkuranel]

And yes, if you dissolve 723,8 grams in 1 liter RO and dose 1 ml from this stock solution to your 380 liter tank, than you will increase your NO3 content by 1 ppm. It is the same with above calculation.

But to dose every day?? I would not do that.

 

[herring_fish]

Ok I have quickly read the entire thread. I was attracted by the title as it has been suggested as a possible answer to my problem. Some of the arguments were thoroughly explored and I am afraid that asking my question might get them started again. Could we please restrict advice to opinions on the mechanics of my problem?

You see, I have a well designed dump bucket styled algal turf scrubber. It had been working well for me for many years. Now many could successfully argue that many parts of my system are not best or even advisable but that is what I like so I would just like input on my specific problem as it relates to the title of the thread.

My scrubber stopped working and I have the symptoms that have been described in the premise. I had a good working, well balance system (at least according to my tastes) but anticipated a large increase in feeding for NPS corals so I decided to run some experiments. I added a very slow flow 55 gallon sump for my 130 display tank a added a deep sand bed but filled the rest of the tank a special coral rubble. This provided too much habitat for bacteria. At the same time I used vodka at a very low level.

Right away, my algae stopped growing, both in the tank and calcareous algae on the rock but my water parameters stayed the same despite very heavy feeding. After more than a year, I started to see pH level rise to fairly high levels.

My water flow rate and turbulence in the bucket is still great so I tried adding iron, iodine and improving the lighting. I read about phosphate limitation so I bought some Phosguard and dropped my pH levels but the scrubber didn't re-start. Then I took the sump off line.

I bought some stump remover and slowly started adding it, a little more each day but was too busy too methodically proceed in a way that I thought was safe so I stopped dosing. My clean rock got a slight coating of something brownish but didn't start any hair algae. After I stopped the fish cleaned the rock back up for me. I still have a nice crop of white hair bacteria on the bottom side of a few or the rocks.

I am getting less busy and will re-start dosing again soon so I would like to get some input on salving this problem that I caused. Are there any other additives that my algae might be missing? Are there any others that are dosing that might have some anecdotal advice from their experience?

 

[mhucasey]

I made a stock solution of Calcium nitrate using 26 grams of calcium nitrate in 1/2L water. My system volume is 106 gallons. Based on the calculator I used, that would mean that 50mL solution would raise nitrate by 3.4ppm in my tank.
I used this solution for spot dosing whenever the nitrate would bottom out to raise the value, with the intent of maintaining nitrate at 2-3ppm. My testing seems to confirm that this is accurate.

After getting comfortable with it, i now have made a vinegar solution with the calcium nitrate that works out to raising the nitrate value of the system by .5ppm for every 50 ml added. This is used for my daily vinegar dosing - my system uses ~36 ml per day.

My nitrates have stayed at 2.5 ppm with this approach, and my phosphates are steady at 0.05 ppm.

I have tried adding larger amounts, to bump nitrates to 5ppm while adding extra carbon, and got a very rapid drop of phosphates, but also saw some cyano a couple of days later when the extra bacteria created by the dose(and that were not skimmed) died off.

I prefer keeping the value stable, as the coral colors are better and the bounce-back cyano is minimized.

And, by the way, I am obsessive with tank maintenance, but i have a lot of fish and I like to keep them fed...

 

[wonderz]

After getting comfortable with it, i now have made a vinegar solution with the calcium nitrate that works out to raising the nitrate value of the system by .5ppm for every 50 ml added. This is used for my daily vinegar dosing - my system uses ~36 ml per day.

Nice corals. Just a quick question. Doesn't vinegar dosing and nitrate dosing cancel each other out? Since vinegar creates bacteria that mainly consumes nitrates.

 

[mhucasey]

Nice corals. Just a quick question. Doesn't vinegar dosing and nitrate dosing cancel each other out? Since vinegar creates bacteria that mainly consumes nitrates.

Thanks
You need carbon, Nitrogen, and phosphorus to create the bacteria. They are in a ratio, not equal amounts. Most people use the Redfield ratio in which ocean plankton was found to have a ratio of the elements of C:N = 106:16:1. I'm sure that the bacterial ratio is slightly different but the concept still applies.

The problem that I'm attempting to address is that fish food is heavy with phosphates, and so over time the phosphates get out of balance with the carbon and nitrogen. I would see the nitrates go to undetectable but the phosphate would climb.

Keeping a bit of nitrate present in the system means the system will be either carbon or phosphate limited. I then add carbon to force the system to be Phosphate limited. The phosphates are taken up with the Nitrates and exported via skimmer.

As a side benefit, I've noticed that keeping a couple of ppm of Nitrate in the system has resulted(anecdotally) in richer coral colors, so its a win win.

 

[wonderz]

Thanks
You need carbon, Nitrogen, and phosphorus to create the bacteria. They are in a ratio, not equal amounts. Most people use the Redfield ratio in which ocean plankton was found to have a ratio of the elements of C:N = 106:16:1. I'm sure that the bacterial ratio is slightly different but the concept still applies.

The problem that I'm attempting to address is that fish food is heavy with phosphates, and so over time the phosphates get out of balance with the carbon and nitrogen. I would see the nitrates go to undetectable but the phosphate would climb.

Keeping a bit of nitrate present in the system means the system will be either carbon or phosphate limited. I then add carbon to force the system to be Phosphate limited. The phosphates are taken up with the Nitrates and exported via skimmer.

As a side benefit, I've noticed that keeping a couple of ppm of Nitrate in the system has resulted(anecdotally) in richer coral colors, so its a win win.

Thanks for explanation. I only tried a little bit of carbon dosing, but wasn't sure that it would be effective in dealing with phosphate.

 

[Big E]

The problem that I'm attempting to address is that fish food is heavy with phosphates, and so over time the phosphates get out of balance with the carbon and nitrogen. I would see the nitrates go to undetectable but the phosphate would climb.

The reason your phosphates climbed is because you're dosing too much vinegar and the balance gets out of whack....nitrtates too low. All you had to do was lower your vinegar dosing and the phosphates will drop. You keep your nutrient.......food entering the tank the same.

This was addressed before by others mentioning reducing water changes or other export methods, but since the vinegar is what caused the imbalance it's easier just to reduce dosing.

At first it was hard for me to wrap my brain around the idea of reducing what was initially used to lower phosphates and nitrates, but that's how it works. Even the old vodka directions say to cut dosing in half when you get to desired levels.

I've been dosing vinegar for 15 months and only dose 8mls a day for a 90g system. I use carbon passive for clarity and a skimmer along with 10% weekly water changes. This makes it very easy for me to control things.

Took this shot a few days ago.......

[/IMG]

 

[mhucasey]

The reason your phosphates climbed is because you're dosing too much vinegar and the balance gets out of whack....nitrtates too low. All you had to do was lower your vinegar dosing and the phosphates will drop. You keep your nutrient.......food entering the tank the same.

This was addressed before by others mentioning reducing water changes or other export methods, but since the vinegar is what caused the imbalance it's easier just to reduce dosing.

At first it was hard for me to wrap my brain around the idea of reducing what was initially used to lower phosphates and nitrates, but that's how it works. Even the old vodka directions say to cut dosing in half when you get to desired levels.

I've been dosing vinegar for 15 months and only dose 8mls a day for a 90g system. I use carbon passive for clarity and a skimmer along with 10% weekly water changes. This makes it very easy for me to control things.

Your reef looks beautiful, and things are doing well in there. I think comparing your qty of vinegar to mine is not applicable though. The two tanks are not comparable, so its an apples to oranges comparison. I can almost guarantee I have a much higher bioload in my tank to start.

I used the dosing instructions when I started adding vinegar, and brought the amount up gradually until algae didn't grow on the glass at all(cleaning the glass every 3 or four days, mostly whitish bacterial haze) and I started seeing the white bacteria on the underside of rocks, pipes, etc. At that point I was dosing 55mL per day. I cut that back to 30 ml(almost 50% reduction), and then have tweaked the amount a bit up and down to where I am at now. If I drop the amount down I end up with green algae on the glass that needs to be cleaned at least once a day to see the tank. Where I am at seems to be a nice balancing point.

 

[coralreefdoc]

Thanks
You need carbon, Nitrogen, and phosphorus to create the bacteria. They are in a ratio, not equal amounts. Most people use the Redfield ratio in which ocean plankton was found to have a ratio of the elements of C:N = 106:16:1. I'm sure that the bacterial ratio is slightly different but the concept still applies.

The problem that I'm attempting to address is that fish food is heavy with phosphates, and so over time the phosphates get out of balance with the carbon and nitrogen. I would see the nitrates go to undetectable but the phosphate would climb.

Keeping a bit of nitrate present in the system means the system will be either carbon or phosphate limited. I then add carbon to force the system to be Phosphate limited. The phosphates are taken up with the Nitrates and exported via skimmer.

As a side benefit, I've noticed that keeping a couple of ppm of Nitrate in the system has resulted(anecdotally) in richer coral colors, so its a win win.

Finally, someone who gets it and doesn't let anecdotal evidence determine their position/opinion(s) relative to this advanced topic :thumbsup:

Exactly what Ive stated in the origins of this thread, but without the legitimate/rightful dose of caution. Very few ReefKeepers should be attempting this advanced practice ...

swcc. While I understand your position(s), despite how biased/trivial the information/facts theyre based off are, you should read above in order to better understand this phenomena/practice. You'll undoubtably learn something, if youre not close-minded

 

[ReefKeeper64]

I wanted to share an update with everyone. Like I mentioned earlier, I dose carbon using bio-pellets, use a large skimmer, Nitrates are always 0 but phosphates are a constant battle requiring lots of GFO. PO4 readings range from 0.08 to 0.25. Note that last weeks PO4 test measured 0.25.

I started dosing Calcium Nitrate yesterday. I didn't have a way to measure granules in grams so I started with a swag 1/2 teaspoon of the granules diluted in a 1/2 liter of bottled water. In small increments, I was able to gradually raise the Nitrates to 5ppm but it took all 500ml of the watered down solution to get there.

By this morning the nitrates had dropped back down to 2.5ppm thanks to the bio pellets so I added another 1/2 tsp of Calcium Nitrate and the nitrates rose to 20ppm. I expect that by tomorrow, the nitrate level wiill have dropped a bit and soon I'll have dialed in the amount needed per day. P04 is still high at 0.23 but I'm pleased with the process so far.

mhucasey, Thanks for sharing your processes. Judging by the vibrant pictures of your tank and your P04 numbers, the nitrate adds are working very well for you.

Chris

 

[2hands]

I wanted to share an update with everyone. Like I mentioned earlier, I dose carbon using bio-pellets, use a large skimmer, Nitrates are always 0 but phosphates are a constant battle requiring lots of GFO. PO4 readings range from 0.08 to 0.25. Note that last weeks PO4 test measured 0.25.

I started dosing Calcium Nitrate yesterday. I didn't have a way to measure granules in grams so I started with a swag 1/2 teaspoon of the granules diluted in a 1/2 liter of bottled water. In small increments, I was able to gradually raise the Nitrates to 5ppm but it took all 500ml of the watered down solution to get there.

By this morning the nitrates had dropped back down to 2.5ppm thanks to the bio pellets so I added another 1/2 tsp of Calcium Nitrate and the nitrates rose to 20ppm. I expect that by tomorrow, the nitrate level wiill have dropped a bit and soon I'll have dialed in the amount needed per day. P04 is still high at 0.23 but I'm pleased with the process so far.

mhucasey, Thanks for sharing your processes. Judging by the vibrant pictures of your tank and your P04 numbers, the nitrate adds are working very well for you.

Chris

you may want to slow down on your nitrate addition. if you dose too much nitrate at a single time you can get a bacteria bloom since you have surplus of carbon with the bio-pellets.

please share the details of your experiment over the next few weeks.

 

[mhucasey]

I will second being careful when adding the nitrate, as a bloom of bacteria that is too robust can be bad as well. Im very interested to see what happens in your system - since you are using the biopellets you should have plenty of carbon for the bacteria growth.

Please keep us in the loop as to what you find