Jump to content

Hello from Souhern China

Recommended Posts

The Miracle gro if diluted right should come out to ppm of 252-84-168  Which should be much higher then  fish poo

They start with 24-8-16 for some reason. And that is just a standard fert we all know of.  They suggest a mix of 0.504 grams to a liter.  I will go over my numbers when I get back and see what else is here.

Share this post

Link to post
Share on other sites



First, you're not drinking the water from the system are you?  The data you're looking at as far as what you're calling "N" is actually talking about nitrates in drinking water.  This would only apply to aquaponics if you are drinking the water from the system.  There is no risk of excess "N" in your vegetables because the plants absorb the nitrates and use the nitrogen to make proteins, which are the plant material.  This is how plants grow.  This is the same process they use when they grow in soil.  I would recommend getting some books about the subject because I'm concerned you may have a very serious misunderstanding about how the whole process works.


Second, most aquaponics systems attempt to remove solids because the grow beds do a terrible job of filtration.  Without filtration, as you said, the fish poo goes right back to the fish tank.  We don't want the fish poo in the fish tank because it's bad for the fish.  iAVs uses a sand bed, which is excellent filtration, so it doesn't need the solids to be removed beforehand.  A mineralization tank is used in many systems to give the bacteria time to break the fish poo down into the nutrient salts that the plants can absorb directly.  Then the "clear" water can go to the plants and back to the fish tank.  These nutrient salts, like nitrates and phosphates, can be tolerated by the fish in reasonable concentrations, but the ammonia and nitrite produced during the decomposition process would be toxic.  iAVs doesn't require this because the solids are caught by the sand, and the mineralization process happens there within the sand, so that the water flowing out the bottom of the sand bed will only carry nutrients which have been fully mineralized.  This is why there is an article on the iAVs website called "Aquaponics' Biggest Mistake" which points out the problem with replacing sand with gravel.


Third, giving plants too much chemical fertilizer is not like putting them on growth hormones.  Plants can only absorb so much in a given environment, and even in optimum conditions, there are still limits to what the plant will do.  True hydroponics tries to optimize growth by providing exactly as much as the plant can use of the exact nutrients it needs.  Aquaponics and soil growing are far less precise.  Mostly, we look for deficiencies and try to correct them by adding something.  Farmers test their soil and know approximately what their crop will need based on research done by universities.  Then they add what is likely to be short.  When you add too much, the extra is washed away by rain before it can be used by the plants.  The issue of plants being damaged by excess fertilizer use is more often encountered when salts have had time to build up without being used or washed away, but this doesn't generally make the vegetables toxic, it just makes them not grow well and possibly die.


In any aquaponics system, these salts will build up in the water if you don't have enough plants to absorb them or if you have too much of a certain nutrient for the plants you grow.  If it's the nitrates getting too high, grow more greens;  if it's phosphates, try tomatoes or peppers.  Just remember:  Don't drink the system water.  It' good for the plants, and it's not bad for the fish, but it is not for human consumption.

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...