Backyard Aquaponics
http://backyardaquaponics.com/forum/

Nitrate & protein (in fish food)
http://backyardaquaponics.com/forum/viewtopic.php?f=1&t=30541
Page 1 of 1

Author:  7341 [ Jun 11th, '19, 16:53 ]
Post subject:  Nitrate & protein (in fish food)

I saw a video not too long ago with someone saying;

"if your growbed is full & the Nitrates are still going up,don't stop feeding the fish because other essential nutrients will start lacking,get a lower protein food for the fish & Nitrate will reduce"

Can anyone confirm if that's true?

I would have thought it would make a slight difference but nothing significant.

Author:  danny [ Jun 11th, '19, 22:26 ]
Post subject:  Re: Nitrate & protein (in fish food)

That's right; the amount of ammonia released from the fish is determined by the rate of protein catabolism; which is higher when protein is being used as an energy source. It depends which fish you have, but lipid and carbohydrate are cheaper forms of energy, and feeds proportionately higher in these energy sources will lead to a reduced rate of protein catabolism, less ammonia, less nitrate.

Having said that, my philosophy would be to feed the fish the appropriate aquaculture feed, attempt to achieve the lowest FCR (feed conversion ratio) and then top up water with potassium, iron, calcium etc to try and get the best balance for plants.

A more logical solution to high nitrates is surely more plants, or a lower feeding rate/less fish.

On a related note; pumping feed through fish in order to achieve good plant growth is not a sustainable use of resources, as you are essentially using feed as a fertilizer. The feed used should be aimed at raising maximum possible amount of fish in order to be environmental sustainable, then the max amount of plants on the waste nutrients.

Author:  montecarlo [ Jun 12th, '19, 04:29 ]
Post subject:  Re: Nitrate & protein (in fish food)

danny wrote:
Having said that, my philosophy would be to feed the fish the appropriate aquaculture feed, attempt to achieve the lowest FCR (feed conversion ratio) and then top up water with potassium, iron, calcium etc to try and get the best balance for plants.


Can you expound upon this? When you say FCR, do you mean conversion to fish mass or plant food?

Author:  danny [ Jun 12th, '19, 08:42 ]
Post subject:  Re: Nitrate & protein (in fish food)

I mean to fish.

Using fish feed to produce plants is not a sustainable use of resources, there are much more sustainable fertilizers for growing plants than fish feed, which is industrially processed and contains wild fish etc. So the fish feed should be used to produce as much fish as possible, which also means trying to produces the least possible amount of fish waste (people might be tempted to do the opposite in AP, just thinking of the veg), but there is always some, and thats where growing the plants enhances the sustainability of growing the fish; as a valuable by-product.

Author:  7341 [ Jun 12th, '19, 12:51 ]
Post subject:  Re: Nitrate & protein (in fish food)

Thanks a lot!
It's hard to believe a lot of things you see on the internet,I didn't know if it was a wind up :lol:.

My Nitrate sits between 20 & 40 ppm but the growbed isn't full at the moment.I've gone with "least fish as possible" route.

Author:  danny [ Jun 12th, '19, 16:08 ]
Post subject:  Re: Nitrate & protein (in fish food)

What kind of fish have you got?

Author:  7341 [ Jul 7th, '19, 23:36 ]
Post subject:  Re: Nitrate & protein (in fish food)

danny wrote:
What kind of fish have you got?

Sorry danny,I was meant to reply the last time I was on here but forgot.

I only have one (system) indoors with gold fish now,I can't afford to keep the heat going for the Nile Tilapia all year round & I wasn't aloud to keep my green house which was where the 1500L system was.

Page 1 of 1 All times are UTC + 8 hours
Powered by phpBB® Forum Software © phpBB Group
https://www.phpbb.com/