Backyard Aquaponics
A place to discuss aquaponics

Is it possible that with so much water for the amount of fish that the nitrogen is too diluted for rapid plant growth?

I am looking at adding some more grow space for my system. What I am thinking is to add a 320 gallon water trough with gravel. I would like to put in a sump system but I cant dig a hole in my yard to get the sump low enough. What I am thinking might work instead is to have a barrel connected next to the grow bed with a sump pump in it. when the water gets high enough in the grow bed the over sized pump will pump all the water back into the FT which is large enough to handle the increased amount of water. A small continuous pump would then slowly fill the grow bed back up. Has this been tried? My only fear is that the sump pump may fail from cycling so often and then the small pump may pump out the FT. I would not put the small pump very deep in the FT so that I wouldn't loose all my water and fish. I could also block up the new grow bed so that if it over flows it would just over flow back into the FT. What do you guys think?

Welcome aboard, Machineman!

Small continuous pumps tend to clog, but it can work. Timers help. Is there any way to raise the fishtank? Or can you pump up to growbed and drain back to fishtank (no sump), possibly?

From your readings you clearly do not have enough fish doing their thing and, at our current temps, they won't do much for a while. Adding the Maxicrop (even with added N, since your N is so low) should be fine. Chappo's suggestion of foliar spraying is a good one, of course, but it does complicate the beautiful simplicity of the concept of AP.

If you were to add urea, be aware that it (or some other N fertilizers) will gradually turn into ammonia before being converted into 'ites and safe 'ates, so don't risk going over 1ppm! For 1600gal that would be about 10grams of urea, then wait a week before adding more (or simply test to make sure the spike is declining) as it takes a few days or more before all decomposing.

No need to add more growbeds yet, but when the fish start to grow you might want as much as 4'x20'. And if you have a friend with some composting earthworms toss ten (or a hundred) into the growbed to prevent clogging.

Have fun!

Or might you have a sump/growbed like so, but with wider containers? Total height is only about 26". The pump runs 24/7, but is in clean water:

Re dilution of N: with lots of water you get the benefit of slow fluctuations in O2, various forms of N, and temperature and those all make it much easier on the fish and are a lifesaver if power goes out and you have no backup. On the other hand, it will take a while for 'ates to build up to where the plants are happy, but some folks have great success with undetectable levels of 'ates (<3ppm?). You may be having trouble with low nutes: plant color will tell you. I'd be happy to show you a pic of my plants for size/color comparison purposes: the beets and chard are still quite small and have been growing for a month, but have put on some good growth with the last week of sunshine. The rats have eaten the broccoli.

I am starting to add to my system. With the rising temps I am in need of way more GBs. I am starting with 2 55gal drums cut around the middle with a sump. This will almost double my current GBs. I found this great drain tube for the auto siphons. It is a 3/4" conduit connector I figure I can put a 3/4" hose on it and straight to the sump. It only comes in 1/2" and 3/4" but I have a small pump and this should be large enough.

Ive got 4 new grow beds almost ready. Just need gravel and maybe a larger pump. I have 1/2" autosiphons with 2 half drums as a sump. The siphons drain too fast for the current pump so I need a new one.

I have a few more pics of my system. I couldent get a good pic of the cats this it the best I got. You can see the watercress in the top of my filter. I cut it all down and what you see it about 3 weeks growth.

Those black grow beds next to the pool look like you are flooding them too deep. Generally it is best not to have water over top of the gravel unless you are growing water/bog plants.

yeah, you are right. They were good but the table has settled and now I need more gravel. I dont grow much on flooded side. Thanks

Darn shifting sands.

I've noticed in grow beds that even gravel will settle over time.

Took some pics of my system. Look at the difference between the watercress in the last photos I posted Mar 5. I also transplanted some of my chard and broccoli from my floating beds to my new barrels.

more pics

Drop your flood level in the black tubs... generally we suggest only flooding to about 1" below the media surface...

Otherwise algae may form... preventing oxygen from being drawn down through the media and oxygenating the plant roots...

Im shutting down the black GBs because of that reason.