Ever wondered how much phosphate is in frozen food?
Well I have and decided to test for just how much is present.
I may need some input on the maths/calculations but this should illustrate just how much 'free' phosphates are present in gamma frozen fish food.
The experiment
I started the test by measuring out 200ml of RO water - ro water has undetectable phosphate and zero TDS.
Next up the food selection - i like gamma blister packs and so do my fish and corals!
Take four cubes and add to your stock (sounds like a Delia Smith recipe)
Nice looking stock there - drink anyone?
I let this settle and then extracted as clear a sample as possible from the 'stock' and assembled the Hanna checker.
Counting down.....
And the final result is 2.5 ppm of phosphate (maximum reading for Hanna)
I also tested using the seachem kit for comparison. I think this shows its over 3 ppm but not much over!
Analysing the results:
So there is at least 3 ppm of phosphate in 200 ml of water using four cubes. Therefore by defrosting your frozen cubes, you can eliminate the 'free phosphates'. What do you mean 'free phosphates'? Well these are the phosphates that are trapped during the flash freezing process but can be removed by rinsing the food in RO water. Obviously all
food contains yet more phosphate but I am not measuring this today!
So how does this effect my tank? Well every time you add four cubes directly to the tank, you are adding phosphate...
Edit: lots of discussion around the benefits of adding the whole cube but I am not convinced the juices contain enough beneficial elements to outweigh the negatives, especially wi the larger prey such as mysis. You can simply defrost your cubes, let them settle and carefully pour away much of the excess liquid or even use a rotifer sieve if you you like!
The maths bit:
200 ml = 3ppm
l litre = 0.6 ppm
500 litre = 0.0012 ppm
Each time you add 4 cubes to a 500 litre system, you increase the phos by 0.001 ppm. Not much to worry about? Yes and no. In just one month (assuming you feed 4 cubes a day) the phosphate levels are set to increase by 0.03 ppm which is almost certainly pushing your tank into unwanted high levels given you are probably already running at 0.03 or higher?
Obviously you can counteract these effects by using phos remover but hopefully I have illustrated its always worth a
wash before mealtimes!
Cheers
Adam