Backyard Aquaponics
A place to discuss aquaponics

What can I add to my fish tank while I have no fish in my 300 gal system.

If you're not going to be without fish for long there might be enough residual nutrients to keep the system running. Usually this works best for older systems. Blood and Bone is another option that some use. Gordon (Gunagulla) and Gabe have both had success with this. The amount I have in my notes;

You'll have to take a look to see what size system Gordon has but I believe he uses 100-200g Blood and Bone, along with a similar amount of Seasol, every couple of weeks. The NPK analysis varies on Blood and Bone (all three should be present - 9.9%N, 3.7%P, 7.4%K is an example that was used in one case). Use some caution if fish are in the system. There haven't been any issues that I know of but it's possible that ammonia could spike as the organic nitrogen is converted from it's initial state.

People have also used aged urine but don't do this if you're on medication.

I'm sure other things would work too.

Edit: This thread gives you the area Blood and Bone was applied to with the dosage listed above and is where I got part of the information - http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=22138

People have also had reasonable to good results with a seaweed extract.

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Meds free Pee works well.. a nightly visit..

Worm Farm Juice...

Chook Poo tea ..
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Nothing quite like the thrill you get from taunting fate by using warm-blooded animal poop. It's like a lottery! Maybe this time you'll get salmonella. Maybe next time.

I am referring to the commercial and fully processed product..

I was advised that it was sterilized. In its processing..
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Scotty is spot on and I can only add that yes there has been many documented systems ran without fish for many months without input, but this may depend on system age. I'm not sure.

Temperature would be my only concern. If snow or extreme low temps are expected then it's very possible the bacteria colony would die off. Although, I wonder if some bacteria may hybernate and then recover? Sorry, typing and thinking at the same time.

P.s. Scotty, you take notes? Man you got it bad. I love it!!

Yes it's true Sad, I know