API tap water conditioner


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Apr 2, 2021
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So after reading very conflicting things about Prime I thought I'd give API a go, mainly because of the plant fertiliser drama. I've never had an issue with Prime and I've always added ferts with the new water...but from what I've read this is pointless as the Prime makes the ferts useless? I was always told to treat for the whole tank regardless of how much water I change out but again, conflicting thoughts about that too.

My water is treated with Chlorine and not Chloramine, the directions on the bottle say to dose 1ml for every 76l of aquarium water to detoxify chlorine...my tank is 240 litres and I do about 50% a week....but I've never measured specifically because I siphon straight out the window onto the grass.

So my question is, do I treat the whole tank or just the new water? What do you guys do?
Do you refill with a hose or a bucket?

I emailed API to ask and this is what they said
"If pre-mixing water, you are able to just add only the amount for the exchange.
However, when adding water directly to the tank from a hose, you will need to dose the amount for the entire aquarium gallons. This ensures that the product is adequately mixed throughout, for proper and immediate dechlorination. To keep your fishes safe."

I use a bucket so I dose each bucketful at the dose rate for the volume of water in the bucket
Thank you, I use a hose 👍🏻 from my calculations then, am I right in thinking the dose is 3.17ml for 240l? I have a syringe so I can do 3.2ml. My ADHD brain doesn't always see what's obvious so I'd appreciate some confirmation 😁
yeah, I have a 75g and i use api and i don't want to waste it so I get around 4- 5 gallon water buckets and put in a ml for each of them.
It worked well for me, I feel like it's more simple and straightforward than all those fancy conditioners like Seachem prime and API stresscoat
First your question about Prime and plant fertilizers. Prime like most conditioners detoxifies chlorine, chloramine and heavy metals; Prime also does more with ammonia, nitrite and nitrate but that is another issue. Heavy Metals include four plant nutrients, namely iron, copper, manganese and zinc. But the problem is how Prime detoxifies compared to API's Tap Water Conditioner. There is a chemical in Prime that supposedly does the heavy metal bit, and I cannot remember the name (Seachem will tell you if asked) but this chemical prevents the uptake of these nutrients by plants. That raises the question of using a fertilizer like Flourish Comprehensive or any other which will obviously contain these heavy metals (at safe levels) in conjunction with Prime. I asked Seachem about this a feew years back, and they wrote back and stated very clearly that the handling of these heavy metals by Prime prevents plants from assimilating them for 36-48 hours. Prime loses all effectiveness after this period. They advised not dosing Flourish because Prime would affect it negatively. There is also an oxygen issue tied in with this, I can't remember details.

The API does not contain this chemical, and the heavy metals although somehow detoxified can still be taken up by plants. So it is safe to add Flourish (or another similar comprehensive supplement) right after the water change to benefit the plants. This is important for more than one reason. One reason being that a water change usually adds more dissolved CO2 (in the tap water), this is what causes the bubbles. This CO2 will benefit the plants. Ensuring the other nutrients are also replenished will benefit the plants even more.

As for how much...you only need to condition the fresh tap water being added. There is no reliable evidence that anyone has ever provided to prove it has to be more when the water is being added directly to the tank. Manufacturers would be happy to sell twice as much if they can convince you otherwise, but there is no evidence. I never had issues doing this.

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