# how much prime to use during water change



## Left C

I've do it two different ways. After draining with a Python, I add the amount of Prime for the whole aquarium and then add my water. I may be able to get by with less Prime, but this works for me. I'm amazed at how fast Prime really works.

When I use buckets, pitchers, etc. I add two drops per gallon from a 50 mL Prime bottle that has a flip up cap made to dispense drops. When the bottle gets empty, I refill it.


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## Phish

okay well I dont have a drop dispenser thing so um, how full should I fill the cap on the 250ml lol


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## rich815

Left C said:


> I've do it two different ways. After draining with a Python, I add the amount of Prime for the whole aquarium and then add my water. I may be able to get by with less Prime, but this works for me. I'm amazed at how fast Prime really works.


This is exactly how I do it too. The instructions for amounts are on the bottle but I use two capfuls into my 72 gal that is 50% down, then add the water to the top. 

I'd do about 1/2 capful for your 20 gal and 1/4 capful for your 10 gal.


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## Phish

okay cool and that is total right, not per bucket of water I use?


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## belladee

Left C said:


> I've do it two different ways. After draining with a Python, I add the amount of Prime for the whole aquarium and then add my water. I may be able to get by with less Prime, but this works for me. I'm amazed at how fast Prime really works.
> 
> When I use buckets, pictures, etc. I add two drops per gallon from a 50 mL Prime bottle that has a flip up cap made to dispense drops. When the bottle gets empty, I refill it.


Wait.. so you add the amount required for the whole tank? So if you have a 70gallon tank and add back 10 gallons, you add enough for 70 gallons?

I just prime what I add back. Like if I add 10 gallons of water back I add 1ml of prime. should I be adding more?


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## Left C

belladee said:


> Wait.. so you add the amount required for the whole tank? So if you have a 70gallon tank and add back 10 gallons, you add enough for 70 gallons?
> 
> I just prime what I add back. Like if I add 10 gallons of water back I add 1ml of prime. should I be adding more?


Seachem mentions two different ways to do it in their instructions, but you have to "clear the smoke and read between the lines" to understand what they are saying and implying.

From: http://www.seachem.com/Products/product_pages/Prime.html This is also written on the 100, 250 and 500 mL bottles of Prime.
"Directions: Use 1 capful (5 mL) for each 200 L (50 gallons*) of new water. ... For smaller doses, please note each cap thread is approx. 1 mL. May be added to aquarium directly, but better if added to new water first. If adding directly to aquarium, base dose on aquarium volume. ..."

Do you see that they mention two different ways to add Prime?

Also, the threads in the cap extend about half of the way up. 1 thread is 1 mL which is enough to add to 10g of water. 1 thread is about 20 drops from the 50 mL bottle. 

Most of the time when I top up an aquarium, I use a pitcher or bucket to hold my tap water. I add the amount of Prime for the pitcher or bucket by the drops. When I do large water changes with my Python, this is when I add enough Prime to treat the whole aquarium.

I really like those little 50 mL bottles and just squirt out 2 drops per gallon. It is easier than trying to measure out 1 mL by the threads. You can get them at Pet Smart.

When I do my large water changes, that is when I dose an whole aquarium's worth of Prime.

Something that isn't mentioned is how much Prime is too much. Like, what is the LD50 for Prime? I don't know. That is why I use two different methods. I know that at times I double dosed Prime and I didn't have any problems at all.


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## Left C

Phish said:


> okay cool and that is total right, not per bucket of water I use?


That is the total.


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## Hoppy

I always dose Prime for the total aquarium volume, and add it as I start refilling after a 50% change. My reasoning is that Seachem believes it takes a minimum concentration of Prime in the water to make it effective, however much chlorine or chloramine is in that water. I think this may actually be true, because obviously there could be a pretty big variation in how much is in the tap water, but they specify a single dosage amount, without concern for how much is in the tap water. I recall reading a forum response from Seachem where they said not to be concerned about overdosing as long as you are close to the bottle instruction amount.


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## michu

Oh for goodness sakes... i am a complete idiot. All this time i have been carrying buckets for a 150 gallon tank, 4 gallons at a time and pouring because I was afraid to add the prime first. LOL My life just got a whole bunch easier... time to break out the python.


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## belladee

I called the company that makes prime.

they said just dose the water you are adding, not the volume of the tank. You can dose the column of the tank but it is not necessary and they said you can add it before, during or after just do it at the time of the water change.

Editing one month later: I now see on their own site they say if you are adding the water to the tank directly dose according to tank volume! So the lady I talked to was mistaken...or we had a misunderstanding


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## Rod Hay

Phish said:


> okay well I dont have a drop dispenser thing so um, how full should I fill the cap on the 250ml lol


You _really_ need to get one then! Because Prime is so concentrated, I have found it dangerous when dealing with very small tanks. I have killed WCMM in a 5g tank - twice.:redface: (It took the second round to make the connection. I still really, really regret this. So sorry little fish!) I highly recommend understanding the correct dosage and using a proper measuring devise. No guestimates.



Left C said:


> Most of the time when I top up an aquarium, I use a pitcher or bucket to hold my tap water. I add the amount of Prime for the pitcher or bucket by the drops. When I do large water changes with my Python, this is when I add enough Prime to treat the whole aquarium.
> 
> I really like those little 50 mL bottles and just squirt out 2 drops per gallon. It is easier than trying to measure out 1 mL by the threads. You can get them at Pet Smart.
> 
> When I do my large water changes, that is when I dose an whole aquarium's worth of Prime.


This is EXACTLY how I use Prime in my tanks. GMTA!


Left C said:


> Something that isn't mentioned is how much Prime is too much. Like, what is the LD50 for Prime? I don't know.


Important point. A double dose maybe okay for most fish, but a triple dose - lethal for some. And, a double dose just treating water you're topping off, or adding back 10% or 20% by buckets; is entirely different from tripling a 50% waterchange adding back to the full volume of the tank!



Hoppy said:


> I recall reading a forum response from Seachem where they said not to be concerned about overdosing *as long as you are close to the bottle instruction amount.*


I highlighted this for emphasis. Again, close to the amount instructed.

Seachem has a sub-forum on the other planted aquarium website. Here is where the discussion ran about overdosing Prime:
http://www.aquaticplantcentral.com/forumapc/seachem/15305-prime-overdose.html

Hoppy, you actually posted during this discussion!




belladee said:


> I called the company that makes prime.
> 
> they said just dose the water you are adding, not the volume of the tank. You can dose the colume of the tank but it is not necessary and they said you can add it before, during or after just do it at the time of the water change.


I forsee you have now started a controversy!!!! Are you quite sure you undestood them; and they you???


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## Hoppy

This question comes up very often. And, that's because the logic involved isn't very clear. What is clear is that Prime doesn't have to be dosed extremely accurately in order to not harm the fish/shrimp. Seachem clearly said that 5 times the recommended dosage is as high as you should ever go, but following the 1 ml per 10 gallon recommended dosage is the best way to do it. I think LeftC had the best answer - either dose the container of change water at 1 ml per 10 gallons before adding it to the tank, or dose the partly filled tank at the 1 ml per 10 gallons full tank capacity as you refill the tank. If you are doing a 50% water change you will be initially dosing the tank at twice the recommended dosage, which Seachem clearly said is not going to do any harm. But, if it is an 80% water change, then dosing the tank as you add the change water would put you at a 5X dosage initially, which might be iffy. The obvious fix for that is to dose half the Prime initially, then dose the second half as the tank gets closer to being full. And, dosing nano tanks requires nano dosing techniques.


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## belladee

Hoppy said:


> - either dose the container of change water at 1 ml per 10 gallons before adding it to the tank, or dose the partly filled tank at the 1 ml per 10 gallons full tank capacity as you refill the tank.


I just dont get this. I want to understand... If you take 10 gallons out of a 70 gallon tank and then add back 10 gallons to the tank directly (with a python) WHY not just dose the 1ml? WHY dose 7ml? Why retreat the rest of the tank water?


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## kid creole

belladee said:


> I just dont get this. I want to understand... If you take 10 gallons out of a 70 gallon tank and then add back 10 gallons to the tank directly (with a python) WHY not just dose the 1ml? WHY dose 7ml? Why retreat the rest of the tank water?


It doesn't make sense. I just treat the water that I took out. If I took 10 gallons out of 70, I might be inclined to not add any at all. Back when I had a 29, if I ran out of Amquel (which I used at the time, instead of Prime), I would just change 5 gallons at a time a couple of times in a week. I slowly transitioned to no Amquel by doing larger and larger water changes. 

I knew a breader that used to not treat his water at all. He had everything you can thing of, Angels, Discus, Africans, GBRs--all kinds of fish of varying types. He used to do 90% water changes on every tank, thousands of gallons every day, and Prime was cost prohibitive.

Today, I does Prime for what I remove. It doesn't make sense to me to do anything else, unless you have more money than you know what to do with. If that's the case, let me tell you about a charity I have been working with. It's called the Human Fund. Write me a check, and I will see that it is put to good use. 

A lot of it is determined by how much of what there is in your water, and it's an expensive and possibly cruel experiment, which is why with my current tank, in a new area, I use Prime.


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## Hoppy

belladee said:


> I just dont get this. I want to understand... If you take 10 gallons out of a 70 gallon tank and then add back 10 gallons to the tank directly (with a python) WHY not just dose the 1ml? WHY dose 7ml? Why retreat the rest of the tank water?


I agree completely that it doesn't make sense. But, as I understand what Seachem tells us, that is what they recommend. My guess is that at a very low concentration, say 1 ml in a 50 gallon tank, there isn't enough prime to do the job. My further guess is that it takes the 1 ml per 10 gallons for Prime to be effective, even for low chloramine concentration in the water.

Almost all of my water changes are done by dripping new water constantly into the tank, and letting the excess overflow out to a drain. This is usually about 4-5 gallons a day in a 45 gallon tank. I don't use any Prime for that, instead running the dripping flow through a whole house type carbon impregnated filter. Some times I add a couple of gallons of new water with a bucket, to help skimming of the water surface after an inadvertent over feeding. That water I don't dose with Prime or run through the filter. But, when I do 50% or greater water changes, I always use Prime at 1 ml per 10 gallons - 4 ml for my tank. That may be more than necessary, but it is still a minute amount to dose, so I continue to do it.


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## Stevie D

Don't try and be scientist and save a couple pennies here and there... there is good reason to do what they recommend. I can tell you for a fact, Seachem has more knowledge than you so don't apply your own rules. 

Hoppy said it best... if there isn't enough in the water, it's useless and you mine as well not use any at all if you want to save money. Prime is one of the most cost effective and cheapest product for an aquarium period! You may be only adding back 10 gallons to a 70 gallon, but how is the prime suppose to get rid of the chlorine in 70 gallons of water with a 10 gallon dose??? 

Chances are if you don't have a lot of chlorine you'd be fine anyway, but if you did why put your fish through that stress?? Chloramines are not removed by letting water sit, so if you do water changes every week and don't remove all of them, they can add up and damage your fish..... DON"T BE CHEAP WITH PRIME... it could kill.

Stevie D


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