I'm dosing trisodium phosphate to get my phosphates off zero ( testing with hanna HI736) I realize I will likely have to dose daily for an undetermined time until I see a rise in value 24hrs later, and then start adjusting dosage . How long after initial dose can I test it? And say if it has already depleted in a couple hours can I dose again right then ? I dosed enough to raise it to .15 today because I dosed enough yesterday for a .03 rise and it was 0 again today.
Dosing phosphates,
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Hanna ULR HI736
ru4serious
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No carbon, no gfo , dinos starting to rear their ugly head as nitrates are low and phosphates 0, dosing , for nitrates, phosphates, phyto and pods. I've been dosing nitrates for about 5 days they are between 5-12 on nyos test kit. I just tested for phosphates again after dosing enough a few hours ago to bring them up to .15 and they are .015 (6ppb) I test again tomorrow
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Phosphates are weird.
I had the same problem and had to keep dumping capfuls of seachem phosphate in my mixed reef and they just kept going into a blackhole. No algae.
Finally they stayed pegged at .05 and didn't dive over night. Whatever feeds on phosphate seems to hit a saturation point and then stops.
My phosphate still falls, but it takes a couple weeks to go from .05 to. 03 and require another dose.
I had the same problem and had to keep dumping capfuls of seachem phosphate in my mixed reef and they just kept going into a blackhole. No algae.
Finally they stayed pegged at .05 and didn't dive over night. Whatever feeds on phosphate seems to hit a saturation point and then stops.
My phosphate still falls, but it takes a couple weeks to go from .05 to. 03 and require another dose.
Oregon Grown Reef
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From what I've researched, phosphate will be absorbed into the rock for a very long time before it finally is at it's saturation point. I'm currently just starting to dose phosphates. They still haven't changed from 0.
Take phosphate dosing slowly though. You don't want to dump in a bunch because you have a zero reading and then wind up with a massive spike. It will eventually reach the point you're dosing it for. The corals are still using some of the phosphate that's available, it's just that the rock depletes it quickly as well.
Take phosphate dosing slowly though. You don't want to dump in a bunch because you have a zero reading and then wind up with a massive spike. It will eventually reach the point you're dosing it for. The corals are still using some of the phosphate that's available, it's just that the rock depletes it quickly as well.
fuelman
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depending on a few factors, like if you started with all dry rock & the tank is only a few months old. it will take quite bit to get off zero. as mentioned the rock will soak it up fast up to a saturation point, then your level will start to rise quickly. so just keep dosing & testing daily till it starts to rise, then you'll need to back off the dose amount at that point to get it dialed in on your target number. my 240g is just shy of 2 yrs old & i still need to dose po4 a few times a week.
For the chemists out there. Is there a way to calculate how much phosphorus/phosphate dry limestone(essentially) can absorb?
It would be interesting to see this as a presoak step before the tank is up and running for culturing dry rock and dealing with all this fun.
It would be interesting to see this as a presoak step before the tank is up and running for culturing dry rock and dealing with all this fun.
Randy Holmes-Farley
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No, not for any normal person.
You'd need to know the accessible surface area, or run a small scale experiment in advance (which some have, the number is really high).
In one case, it took over 50 ppm phosphate to maintain about 0.16 ppm on 5 pounds rock in 5 gallons of seawater water (IIRC).
Would the rock ever get to a saturation point. Where it could then be added to the tank without leaching back into the water? It would be interesting to have a very high phosphate concentration mix and do a dip for some number of days to absorb an amount of phosphate. But reduce the amount it would absorb without significant leaching too.
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Yes and no and no.
"Saturation" depends on the phosphate in the water. The higher the phosphate in the water, the more binds at saturation.
Is there an upper limit? Certainly, but likely at far higher phosphate than you'd want in a reef aquarium.
But ALL of the phosphate can come back off again if the phosphate in the water drops below the point where it is in equilibrium with the amount on the surface.
It is in constant flux. Like a pond evaporating when it is dry, and expanding when it is raining.
"Saturation" depends on the phosphate in the water. The higher the phosphate in the water, the more binds at saturation.
Is there an upper limit? Certainly, but likely at far higher phosphate than you'd want in a reef aquarium.
But ALL of the phosphate can come back off again if the phosphate in the water drops below the point where it is in equilibrium with the amount on the surface.
It is in constant flux. Like a pond evaporating when it is dry, and expanding when it is raining.
