Phosphate remover math help

[USMA36]

i am looking at trying Brightwell Aquarics Phosphat-E. The bottle says 1 ml will remove 1ppm of phosphate from 4 gallons. I have a 100 gallon tank with .1 phosphate. If I add 1.25ml 1 time that should drop my phosphate to .05. Is my math correct? What’s the best way to add this? And how often should I add it?

 

[Flippers4pups]

i am looking at trying Brightwell Aquarics Phosphat-E. The bottle says 1 ml will remove 1ppm of phosphate from 4 gallons. I have a 100 gallon tank with .1 phosphate. If I add 1.25ml 1 time that should drop my phosphate to .05. Is my math correct? What’s the best way to add this? And how often should I add it?

Unfortunately I have no experience with this product. Maybe the #reefsquad knows?

 

[Fudsey]

It's like lathium isn't it? @jsker uses that, maybe he would know.

 

[Oscaror]

i am looking at trying Brightwell Aquarics Phosphat-E. The bottle says 1 ml will remove 1ppm of phosphate from 4 gallons. I have a 100 gallon tank with .1 phosphate. If I add 1.25ml 1 time that should drop my phosphate to .05. Is my math correct? What’s the best way to add this? And how often should I add it?

How is it that I get a 90% in calculus but THIS is what gets me?

 

[Oscaror]

Okay nevermind it didn't get me I figured it out and yes your math is correct

ppm reduced = z
gallons = y
ml dosed = x

The function has 2 variables which is why it was so tricky, but the function would be

When you plug in 1.25ml as x and 100 gallons in as y you get:

Subtract 0.05 from o.1 (your current phosphates) and you get 0.05ppm as you originally calculated

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, phosphate calculations are essentially useless. If you are at 1 ppm in a reef tank and replace 100% of the water with zero phosphate water, you may end up with a high phosphate value again because a large amount of phospahte can come off the rock and sand, and the opposite effect works when dosing it.

 

[USMA36]

FWIW, phosphate calculations are essentially useless. If you are at 1 ppm in a reef tank and replace 100% of the water with zero phosphate water, you may end up with a high phosphate value again because a large amount of phospahte can come off the rock and sand, and the opposite effect works when dosing it.

Are you saying the math used above to determine dosage of Lanthium Chloride (Brightwell Aquatics Phosphat-E) will not be accurate?

 

[Oscaror]

Are you saying the math used above to determine dosage of Lanthium Chloride (Brightwell Aquatics Phosphat-E) will not be accurate?

What makes me wonder then is why they include the information 1ml in 4 gallons reduces 1ppm if it's pointless to calculate anyways

 

[CNDReef]

I think what Randy meant is that it’ll take out 1 ppm but it’ll Leach from the rock back into the water column until it’s balanced out again so you’ll end up with a higher number than you thought you were going to get.

 

[Randy Holmes-Farley Verified Community Expert]

Are you saying the math used above to determine dosage of Lanthium Chloride (Brightwell Aquatics Phosphat-E) will not be accurate?

It is almost certainly inaccurate regardless (even if done correctly, it assumes no other sink for lanthanum than lanthanum phosphate), but it is intended (if that is the correct word for misuse of chemistry) for lowering phosphate in water only, not where most of the phosphate is bound to rock and sand that acts as a big buffer.

 

[Randy Holmes-Farley Verified Community Expert]

I think what Randy meant is that it’ll take out 1 ppm but it’ll Leach from the rock back into the water column until it’s balanced out again so you’ll end up with a higher number than you thought you were going to get.

yes, that's the most obvious issue.

 

[rkpetersen]

Even though your phosphate drop will almost certainly be less than calculated, you should still be pretty careful with dosing lanthanum directly into your DT. You are looking at attempting to generate a pretty small desired drop in phosphate level with a relatively aggressive technique. Use less than recommended, measure the result the next day, and use again if necessary. I'd also try to avoid allowing the precipitate to circulate as much as possible, as some fish are reportedly sensitive to it. Dripping it drop by drop directly into a 1 micron mesh filter sock in the sump seems to work for some.

Another way to think of the math: 25 ml will drop the phosphate in 100 gallons by 1 ppm. You want a drop of 1/20th of that. 25/20 = 1.25 ml.