How much prime for water changes

FishKing5

Aimara
MFK Member
Oct 24, 2013
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Simple question. Should you dose the volume of your whole tank during a water change with prime or dose for just the amount of new water you're putting in if you're doing water changes straight from your tap to the tank. I've heard a few mixed reviews. I do a lot of water changes and have been dosing for the entire volume of my tank every time which sucks since they're a 125 gallon and a 90 gallon growout tanks that get several water changes per week so this prime bill is adding up.
 
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skjl47

Goliath Tigerfish
MFK Member
May 16, 2011
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Hello; I bought a small bottle of Prime a while back. It was not cheap. Did some searching and found that Safe is the same stuff as Prime but in powder form. I did the math and discovered the Safe is much cheaper to use by a lot. I do not recall the exact numbers but the difference is significant.
There is a factor to be considered but not a big issue to my way of thinking. That being the Safe is only stable and useful for around a month once mixed in water. Stable for years in the dry powder form in a the container.
One member was having an issue of how to measure portions of Safe for one water change (WC). My suggestion being to estimate the amount of water used in WC's for a month and premix enough safe in a jug for one month.

good luck
 

RD.

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May 9, 2007
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Jcb1125

Feeder Fish
MFK Member
Jun 27, 2016
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For smaller tanks I dose the whole volume, at work where we have a thousand gallon system, I dose the volume of the water change, Ive noted no negative effects, not saying that you should do that. For a cheaper alternative, if you only have chlorine, look into sodium thiosulfate.
 

Phoenixsg

Gambusia
MFK Member
Jan 22, 2014
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I usually dose per litre replaced,

5÷200= 0.025

Then

0.025 × # of litres to treat.

That's my method based on the figures Seachem advise anyways.

Hope its helpful
 

Bandit87

Candiru
MFK Member
Mar 22, 2016
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I dose what I feel like.. lmao usually pretty close to full volume. Its expensive.. So, if full volume would be 3 caps, I just do two. Lol 50 percents once a week.
 
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