Dosing vs feeding for more nutrients

[cocoReefer]

Howdy, hope all is swell.
Should i start dosing PO4 and NO3?

Want to start a discussion on the pros/cons and opinions on dosing PO4/NO3 or feeding more.
Ideas about high input and high output. Will dosing change other chemistry like ph? Being able to measure and accurately monitor dosed nutes vs harder to measure foods. Types of foods and dosing routines. Tell us what you do.
Anecdotes and evidence. All that jazz.

I have been upping the feeding in my system over the last year. Around 6-10 cubes of frozen food and a nori sheet daily in my 125 setup. Also alternate days of phyto and zoo planktons, along with alternating days of 2 brands of aminos. So, fish are all fat, corals look good and im looking at the next step, but ive never dipped my toes into bottles of PO4/NO3

I measure PO4 and NO3 at the lowest end of my tests consistently. Like, zeros across the board always.

Thanks

 

[arking_mark]

Following.

Generally speaking:
1. Dry food has higher PO4
2. Frozen food has higher NO3
3. Dosing NO3 will increase Alk as its consumed
4. Dosing is probably better for stability

 

[MNFish]

Before Adding I would look at maybe subtracting filtration, for example if you are running a skimmer try running it a few hours less... maybe change filter socks less or not run as many...
If you are feeding that much and nitrates are still super low you might be just filtering too efficiently.

 

[Randy Holmes-Farley]

The advantage of dosing sodium nitrate and/or sodium phosphate is control: exactly how much of what do you want, and avoidance of perhaps unwanted effects of foods, such as consumption of O2, yellowing of water from accumulating organics, cyano consuming organics, etc.

The advantage of feeding more is primarily that it is easy.

Most folks do not realize that dosing nitrate adds alkalinity, so that effect needs to be accounted for.

Dosing with other chemicals can cause other issues. Using potassium nitrate can slowly elevated potassium, and dosing with "stump remover" or other products of unknown purity (even hobby brands of unknown purity) risks impurities.

 

[arking_mark]

The advantage of dosing sodium nitrate and/or sodium phosphate is control: exactly how much of what do you want, and avoidance of perhaps unwanted effects of foods, such as consumption of O2, yellowing of water from accumulating organics, cyano consuming organics, etc.

The advantage of feeding more is primarily that it is easy.

Most folks do not realize that dosing nitrate adds alkalinity, so that effect needs to be accounted for.

Dosing with other chemicals can cause other issues. Using potassium nitrate can slowly elevated potassium, and dosing with "stump remover" or other products of unknown purity (even hobby brands of unknown purity) risks impurities.

Just curious on imbalance to Sodium levels with Sodium based products. Would that ever become a problem?

 

[Randy Holmes-Farley]

Just curious on imbalance to Sodium levels with Sodium based products. Would that ever become a problem?

Not really.

Let's work through dosing KNO3 and NaNO3 for a year at 2 ppm nitrate per day, without water changes, but with a correction to maintain the salinity.

The daily dose is:

0.74 ppm sodium
1.25 ppm potassium

Over 1 year, that is

270 ppm sodium
458 ppm potassium

Assume the seawater is 35,000 ppm total ions at the start, with 10,800 ppm sodium and 400 ppm potassium

in a simplistic assessment, the final total ion weight is:

35,270 for the sodium case
35,458 for the potassium case

Correcting these back to 35,000 by dilution lowers the amount added to:

270 x (35000/35270) = 268 ppm sodium
458 x (35,000/35458) = 452 ppm potassium

So after a year of dosing without water changes we have:

sodium: 10,800 to 11,068 ppm, or a rise of 2.5% (well within the range experienced by new salt mixes)
potassium: 400 to 852 ppm, or a rise of 113% (way outside of the range of variability of new salt mixes)

 

[MNFish]

What I do is when I feed return pump skimmer and circulating pumps get turned off, then after 5 minutes circulating pumps turn on, then after 15 return pump, than at 30 skimmer..... This not only helps to ensure the food is eaten but gives some time to increase nutrients. I also use an algae scrapper but dialed that in as well to allow more nutrients to stay in the water. I think sometimes people have such efficient methods for exporting nutrients that they get stuck in a cycle of adding more but cannot exceed their level of export and too often people focus on the import and not export...

 

[cocoReefer]

What I do is when I feed return pump skimmer and circulating pumps get turned off, then after 5 minutes circulating pumps turn on, then after 15 return pump, than at 30 skimmer..... This not only helps to ensure the food is eaten but gives some time to increase nutrients. I also use an algae scrapper but dialed that in as well to allow more nutrients to stay in the water. I think sometimes people have such efficient methods for exporting nutrients that they get stuck in a cycle of adding more but cannot exceed their level of export and too often people focus on the import and not export...

Well i have adjusted using that method.
My return stays off for 20-30 minutes and my skimmer off for 30 minutes at feeding/amino/phyoto/zoo dosing. Seems to be elevating my numbers the tiny bit i wanted.
Also get more feeding response from corals.

 

[cocoReefer]

@Randy Holmes-Farley
Ive seen you write about your fondness for sponges and other fauna in your tanks. Does NO3/PO4 dosing affect those animals too?