How soon after dosing lanthanum chloride can I test PO4?

[Daniel@R2R]

If I dose lanthanum chloride to lower PO4, how long do I need to wait before retesting?

 

[Gablami]

It works very quickly. When I dosed while I was treating rocks in a Rubbermaid, I would see the cloudy precipitate develop within seconds. I would say the answer depends on your system’s circulation. Once you dose, and the water circulates to equilibrate the level throughout the system, you can test.

 

[flampton]

I would look at it the next day. You need to factor in the equilibration between substrate and water.

 

[csb123]

I would test in a day, for no scientific reason. But I feel that the precipitate may skew the results. I also put the sample thru a coffee filter.

 

[pdxmonkeyboy]

Fwiw. I test an hout after dosing and can see the final result. I am at about 4x turnover through the system per hour.

If you have lots of phos leaching i have found it helpful to test soon after as it only takes about 12 hours for the phos in the water to start rising from inputs from rock.

 

[Daniel@R2R]

Thanks guys! I'm working on correcting a phosphate issue. To be safe, I'll test 24 hours after dosing which should tell me how big a dose I might need as a follow up.

 

[piranhaman00]

Thanks guys! I'm working on correcting a phosphate issue. To be safe, I'll test 24 hours after dosing which should tell me how big a dose I might need as a follow up.

Join us on this thread for newbie LaCl dosing

Did I unlock all the phosphate from 100#s of live rock?

No that’s not right at all. I wouldNT worry too much, there has been many reports of gross overdosing phosphate with little issue do a water change. Hopefully a 28% water change will suffice for tonight then another 28% water change tomorrow . Maybe a water change everyday until the po4 goes down?

www.reef2reef.com

 

[Larry L]

I would look at it the next day. You need to factor in the equilibration between substrate and water.

Agree - the levels in the water might drop fairly quickly, but then if you have a buildup in rocks or substrate, that will cause more phosphate to leach out into the water.

 

[pdxmonkeyboy]

Not to belabor the point, but i would test soon after and 24 hours later. At least the first time you dose. It is POWERFUL stuff. You don't want to be stripping too much out of the water at once.

Chemistry dictates that the lower you zap the water the higher the concentration gradient between rock/water will be and the more rapidly the water will absorb phos.

Just be cautious, i am cerain you will be, but i have started STN with over zelous LC.

 

[Daniel@R2R]

Not to belabor the point, but i would test soon after and 24 hours later. At least the first time you dose. It is POWERFUL stuff. You don't want to be stripping too much out of the water at once.

Chemistry dictates that the lower you zap the water the higher the concentration gradient between rock/water will be and the more rapidly the water will absorb phos.

Just be cautious, i am cerain you will be, but i have started STN with over zelous LC.

Yeah. I'm also staying picky about what I use. I am trusting Phosphate RX (and would also trust Phosban-L) but won't be using ANYTHING that isn't made for aquarium use.

 

[Sleeping Giant]

S

Agree - the levels in the water might drop fairly quickly, but then if you have a buildup in rocks or substrate, that will cause more phosphate to leach out into the water.

I if the tank is treated, it could release more phosphate?

 

[Daniel@R2R]

S

I if the tank is treated, it could release more phosphate?

Yep. If it is bound to your rocks/substrate.

 

[Sleeping Giant]

Yep. If it is bound to your rocks/substrate.

So I would need to dose again? I did 2 days ago and my phosphate was still high, used phosphate Rx, half dose.

 

[Daniel@R2R]

So I would need to dose again? I did 2 days ago and my phosphate was still high, used phosphate Rx, half dose.

My suggestion (what I'm doing) is check your PO4 and then dose accordingly (don't lower more than 1 ppm per day). Next day repeat the process (or next time you dose).