Backyard Aquaponics
A place to discuss aquaponics

Why keep adding Ammonia?

I’m guessing my pump is a bit large. I updated my Gb water lines to 1-1/4” from the 2”, but still the FT keeps flowing up to the top of the SLO. I got it going juuuust about to the top of the slo, but that dumps too much into the first Gb which could be a nutrient problem once things get going. Thinking I need to divert some of the water from the pump to slow the fill?

Also thinking about expansion already which could fix the problem too. Thinking of pvc tubes that use 2” net pots, but seems like I’ll need to make that instead of buy it. Any recommendations for a pvc system off this setup? Figure it’ll need to be a T off the water line from sump, then drain into sump (or ft) as it is now. With so much pump power, hopefully shouldn’t be a problem to pump water to 7ft height, then drain to 3ft, with a pvc snake between. Only drawback I see here is it gets post Gb water, not ft water.

If fish don't arrive for several days or more, the bacteria needs to keep feeding to stay healthy and be ready for the fish.

Looking very nice! If you have too much or unbalanced flow, you can reduce the pipe size at the problem GB or extend the pipe to deliver water at the far side; add a couple 90's, etc. There are many different solutions. Maybe cap off the current outlet for the 1st GB which is right at the FT outlet, and move it down where it is right next to the 2nd GB.

I got some vinyl gutters and got the nft setup going. They’re rectangular, and there’s just a thin film along the bottom. All seems to work well so far. Venturi is a bit small, but I bored it out a bit to make it flow more. Water into the grow beds seems sufficient. For now I’ll keep adding the fish emulsion, growing plants and making it look a little nicer. All input is welcomed!

Been adding the Fish Emulsion (but not for the last week). Below are the water specs:

PH - 7.6
Ammonia - 4ppm
Nitrite - 0ppm
Nitrate - 60ppm

Looks like I need to stop with the emulsion til either nitrate or ammonia drop. Still no fish

Hi mate, definitely stop adding the emulsion until the ammonia level hits 0. Have you seen nitrites?

No nitrites just yet.. It’s only been about 2 weeks, but it’s been fairly warm. I’m guessing about 2-4 more weeks for cycling. I’ve got some plants going, and about to get some red wigglers in the beds.

The nitrates must be from the fish emulsion then, nitrogen cycle; NH3 => nitrites => nitrates.
The warm weather will aid the cycling, you should start seeing the nitrites soon.

Currently debating how many fish to start with.. Likely going with 30-50 largemouth bass.

950L FT water
1175L media (900L wet)
400-500L sump if it matters

I'm struggling to figure out my FT water pump rate and if it's truly once per hour. I have a T going to my NFT, and the Venturi bottlenecking the flow into FT. I'm guessing I'll need to test it by pumping into a bucket, and multiplying accordingly.

Ratio's I've been seeing are

3kg fish per 100L wet media - .5kg bass per 16.6L - 900L/16.6L - 54 fish
20-25L Wet media per 500g fish - 900L/20 and 900L/25 - 36-45 fish

I don't think the NFT has anything to do with this ratio, as there's no media to filter. But it should use up some nutrients. Am I right thinking it's just GB volume that dictates fish ratio? How many fish do you recommend based on these details?

You are correct, there is no bio filtration from the NFT. FT water and wet media are the important things. I typically limit my system to 1 lb fish per 5 gallons water in the FT, and with a 1:1 ratio to wet media you should be okay. I think 50 bass is a good starting point, but you should harvest a few when they approach 1 lb each if you haven't lost any along the way.

I'm not experienced with bass, but with any fish you add will have ammonia and nitrite spikes early on. Watch out for that and be very careful not to overfeed them based on your water parameters. Just because the system is cycled does not mean it will immediately handle 50 fish being fed 3x per day. Research the ammonia toxicity charts that show how it varies based on pH and temperature. High pH and high temp make ammonia more toxic for fish. Not a problem if it remains below 0.5.

I strongly urge you to add 10-20ppm (1-2ppt) chloride salt in your system. This is low enough to not harm your plants or fish but will protect the fish from damage to their gills if you have a nitrite spike. Also many freshwater pathogens do not tolerate salt well, so it helps with disease too. In my experience the most common is Ich which is somewhat salt tolerant, but others can take hold too.

With salt, make sure it does not have any additives. Table salt has anti-caking and iodine added, many water softener salts have anti-rust and anti-caking, etc. Good salts to use are potassium chloride, calcium chloride, sodium chloride. Pool salt, aquarium salt and water softener salt are good sources as long as you get it with no additives. Home Depot sells Solar Salt and Potassium water softener salts that I use. I actually use a blend of NaCl, KCl and MgSO4 (epsom salt) in my system to supplement potassium and magnesium. and minimize sodium.

Calculation is 1 gallon = 8.34 lbs. 8.34 x .001 = .00834 lbs per gallon. .00834 x 900 = 7.5 lbs for 1ppt. Be sure to calculate total water (FT + sump).

Always dissolve the salt in a bucket and add only the liquid brine. Be aware that water evaporates but the salt remains. Only water exchanges will reduce the salt content, and evaporation will increase it.

Early on I had some bad experiences with nitrite poisoning and Ich. I lost 30 catfish to nitrite poisoning (about $100 at the time). A bit later I had an Ich outbreak from introducing some new catfish without quarantine. I had to move all my fish to a quarantine tank with 6-7ppt salt and maintain the water at 90° for 10 days. That killed off the Ich.

Since I had purchased catfish from a source before, I thought they would be healthy. But from then on I quarantine all fish before adding them into my system.

Ich is a parasite that needs fish to complete it's life cycle. So by removing the fish for 10 days it is eradicated in the AP system. And by killing it off on the fish with the salt, the fish are parasite free when they go back into the system. The elevated temp accelerates the life cycle and assures that all parasites are killed within the 10 days.

Wrapped the FT and GBs in wood (at least the fronts). Still working on covering the backs, and supporting the GBs a little better.

I probably added too many plants too soon, and I’m seeing nutrient deficiencies on the plants. I don’t want to keep adding the fish emulsion, adding to the ammonia that’s not decreasing, but would love to add some nutrients that are fish safe and contain no ammonia. Any suggestions? Definitely lacking Iron, and possibly zinc and magnesium.

I’d like to add the salt, but I’m a bit confused on the formula. Are you saying for my 900L fish tank, to add 7lbs of salt? That seems a bit much. Also, the brine you’re talking about is the liquid on top, not the solid salt on bottom, right?

Wow, looking really nice!

A 900l tank is 237 gallons. 237 x 8.34 x .001 = 1.976 lbs of salt for 1 ppt, or 1 lb 15-1/2 ozs. Use a scale. you should invest in a refractometer to measure salt if you will be using it. I am a firm believer that salt absolutely helps prevent many fish diseases.

Those tanks look great, well done.
The easiest way to add salt is to follow the rest of the world and go metric. 1000 litres: 1 kg salt will give you 1ppt
Not sure why you want to add salt atm though? Giving the fish a salt bath prior to adding to the system and buying the fish from a reputable seller will dramatically reduce the chance of fish parasites.
What are you using to check the water parameters?
You can add seasol, the seaweed emulsion, as a nutrient supplement as it will not affect your ammonia levels. It will discolour your water though.