Backyard Aquaponics
A place to discuss aquaponics

I thought I would say hi. This is my first time on an Internet chat forum and I don't know much about computers. My son signed me up and talked me into starting an aquaponics system. He is actually typing this for me. So if I type anything out of the ordinary that is why. Im a complete newbie to aquaponics and the Internet. Hopefully a picture of my system loaded. It's a chift pist with 250 gallon fish tank and 200 gallon sump. I currently have 2 dozen fathead minnows trying to start my bacteria.

I hope to learn more about what is the best ph,nitrite and nitrate levels need to be for the best growth of my 50 catfish (will be stocking catfish Saturday) Current readings are. Ph 7.5, nitrates 20, nitrite 0.5, carbonate 40, general hardness 30. This was tested with a strip.

Thanks

Hi Oaktree, welcome to the forum. Layout looks great, Very nice neat setup . Are you going to be increasing the number of grow beds or increasing the filtration capacity of the system. I'm thinking 50 catfish is quite a few for a system that size (I haven't calculated it out based on what I see at this point though). Watch your Nitrites and Ammonia with the catfish. Salting to 1ppt with salt will help mitigate the effects of the Nitrites -

Salting
Nitrite issues - 1ppt = 1KG per 1000L or 1gm per L

Let us know if you need help - this post slipped through the cracks but usually we're pretty good about replies.

If you don't have one I recommend you get a way to test for ammonia and nitrites if you don't already have one.

If you have high ammonia / nitrite / nitrate levels you can make a filter (of which there are multiple types) to try and bring them out of the system. Once you get plants in ideally you want your pH between 6.5-7, there's a picture around the internet that shows the absorption rates of different minerals and such at different pH levels:



In an ideal system your ammonia and nitrite should be 0, and your nitrate levels should be >20 at all times and <300 or so, based off what I've read / researched.

Hi Oaktree,

Great looking setup you have there, I love the way you have your bearers on the concrete blocks, great support, some people don't like the idea of using the blocks on their end but if you have the weight evenly distributed it's fine.

A full IBC sump is always a great asset it's all looking good.

Have to agree that 50 cats in that will get to a tough spot before long. Very clean looking setup.

I have lost 7 of 48 catfish so far. The most recent today. I added 1 lb of salt 4 days ago. See test results and drain upgrade/experiment in pics. Is the fish loss normal. We just started daily testing on 2nd.

Water is very clear. I fed less than a handful of food today.

Lost? Did they die? If so what did the 'corpse' look like? Anything specific?

With small fish they might have swap up your SLO, is there netting on the bottom of it?

They simply died in the tank. Looked like normal dead fish.

Hard to tell from the pictures. Do you have an air supply of some type providing air to the system? I don't see a lot of surface movement in the fish tank but you may have turned off the flow and air to see the fish.

Good looking system. Sometimes you lose fish especially when adding them to a system. You already salted and tested the water. I usually sit back and let the system do what it was designed to do at this point. I find messing with it too much usually doesn't end well.


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I would say with channel cats it's not that uncommon. Looks like you were running pretty high nitrites for awhile which some fish handle better than others. The salt should help but you may lose some additional fish from damage that already occurred. I'm not certain if additional aeration at this stage will help but it would probably be worth trying.

http://www.aces.edu/dept/fisheries/aquaculture/documents/BrownBlood.pdf

As for air supply, we have a spray bar in fish tank. Fish death pic from today.

Sorry to see your still loosing some. This is one of the reasons I'm a bluegill fan, they seem almost indestructible - unfortunately they grow slowly and the feed conversion isn't great either. Once it warms up where you are those catfish will grow pretty fast provided you can keep the ammonia and nitrites under control

I couldn't use that many fish in an IBC. I moved to an above ground pool bought used cheap since I also removed it and used the IBCs as baffle filters draining the sludge out of the bottom and use it as fertilizer.

Basically with the initial 50 catfish you're at or slightly above the maximum stocking density for that system if you harvest the fish at one pound. It's not a good idea to stock a new system at the maximum levels. Now that you've lost some your stocking levels are still pretty high and you might consider adding some additional grow beds, another IBC tank and additional aeration. There's a chance you'll get by with what you have till they about 1 pound and they won't all grow at the same rate so you may be able to harvest some early and take the pressure off.