Backyard Aquaponics
A place to discuss aquaponics

Okay simple enough question

I understand if you overstock a tank with fish then you really have to micro manage ammonia waste and nitrites and so forth so a bit more demanding than if you understock a fish tank.

But with it being overstocked the nitrates are surely going to be higher and better for your plants

Scenario example

60 Fish, 1000Litres, nitrates would be probably say around 20, so really good for the plants, now lets do the same 60 fish in 10'000 litres of water the nitrates would be maybe 1. Is there an assumption or consensus out there which is the better situation

Thanks

Stocking density is related to ammonia production... and subsequent "nitrification"...

Both through feed levels... oxygen demand... and the amount of bio-filtration

Raising your density... without providing additional oxygenation and/or bio-filtration cpacity....

Will result in MACRO-management.... poor water quality... possibly clogged growbeds over time.... or fish fatalities

For the sake of a few more plants??? ... IMO... Don't do it.... unless you completely understand ALL the variables involved....

And frankly, if you wish to take that path for additional vegetable growth....

Just add extra growbeds... hence extra bio-filtration capacity...

Your plants will utilise the nitrates as they need them.... and it's not uncommon in a mature and balanced system to see readings (ammonia, nitrite, nitrate).... Of 0,0,0 ....

A system with elevated nitrate readings just indicates that it probably isn't planted out to capacity...

Actually that is a very valid point, I was going along the path that the greater the stocking density then greater the nutrient concentration the plants have to access, but realistically as you point out any measurable amounts eg 1 or above of nitrate simply indicates that there is an abundance not being fully utilised

Good thinking

I've had really high nitrates lately as we just came out of the hot humid season when the fish were eating lots but only a few types of plants wanted to grow well. Higher nitrates don't necessarily mean better plants. Remember some plants actually give issues with too much nitrogen.

There are some types of plants that are greedy and tend to use up nitrogen quickly but that won't really help you if your system is over stocked and under filtered. Duckweed and a few water plants are about the only thing I might recommend to help short term while you increase the filtration on a system since duckweed can use ammonia directly, however, it will also use dissolved oxygen over night and it doesn't do anything to help with solids.