solid waste question

[knvernon]

I have a setup on my balcony, using a 75 gallon fish tank, with 28 3-4" bluegill in it, and directly above it I built a 6' wide x 2' long x 12” deep wood grow bed, lined with a pond liner, using a bell siphon to siphon down, with no sump.

Its been running for about 4 weeks with massive plant growth, but im noticing there is a decnt amount of solid waste build up on the bottom of the fish tank.

My question is, what do you guys do with your solid waste? Is it okay to suck the waste from the bottom of the tank up into the grow bed?

[Oliver]

My guess is that you don't have a high enough flow into your submersible pump, which should be in the bottom of your fish tank. Not all of that water should necessarily go to your grow beds, as some of it can return to the fish tank directly, under pressure, helping to keep your fish tank water circulating as well as feeding your grow beds. Jetting water into your fish tank requires ample pump pressure and a reduced pipe size allowing for a high velocity of pump water to be squirted into the tank at about a 45 degree angle. This will circulate the water and help with aeration, which is especially important if your air pump fails.

As we just learned, it is important to keep the water pump and air pump on separate electrical circuits, and we have the dead fish to prove it. We were gone for the whole day and didn't check the system early in the morning before we left and got back late that night. The circuit breaker had tripped the night before taking down both the air and water pumps. This was a stupid mistake on my part as I had checked the power being used by the pump earlier that afternoon, as I had a request for those numbers. When I plugged the pump back into the extension cord I let it drop beside the fish tank instead of placing it back on the lower shelf of the grow bed. During the next fish feeding some water was splashed on the connection and the breaker tripped. Due to the system monitoring, I have a very good idea when it happened, as the feeder did its thing at 5 PM and at 5:11 PM the control valves were not responding. I need to set some alarms.

After returning home the next night, some 30 hours later, I went into the grow room to make some measurements on a grow light size and found the whole system down and 19 dead fish.

The electrician was here today to put in some wire for the solar we are installing but I diverted him to adding plugs on the other circuit in the room so I could plug in the two pumps separately.

Didn't mean to hijack the thread but it seemed like a good time to share that experience.

Oliver

[knvernon]

I've got my air pump with two 8" bubble stones, and my submersible pump on two seperate outlets, and my pump is rated for 295 gph. Ive been timing my cycles once a week since I've started it, and I can get 4 cycles every 1hour and 3 mins.

That's a good cycling time right?

But if I understand what you're saying correctly, my pump isnt strong enough? Which is why the solid waste is settling?

I have the pump set up as an inline pump, and when i clean the tank i fashioned a hose attachment that i just slide on and suck up the waste - which was really my original question, is that okay? Or could that turn out bad for the pump/growbed/plants etc?

[Oliver]

I am unclear on how you are capturing your fish waste solids during normal operation. If you have an external pump, be pulling the water from the center bottom of the tank would be ideal. This requires keeping your tank water in circulation by returning some of the water from the pump back into the tank in such a way that it circulates the water. Your pump size should be adequate as long as that rating is at the height of the grow bed above the fish tank water level. Some pump's flows are rated at zero pressure and some are rated at one meter of head and some don't say.

The other thing I'm not clear on is the shape of your fish tank. I am assuming it is either oval or round. Oval is adequate to allow for circulating water. We use a 29 gallon rectangular aquarium for our indoor aquaponics system and it does not accumulate solids. It has ample jet back from the 360 GPH submersible pump located at one end, and along with the flood and drain from the 25 gallon grow bed, it keeps the water stirred up enough the keep the solids suspended for the pump to grab them.

The numbers you give for your water pump look good for the size of system you are running, but it is the configuration that I do not have a good picture of in order to fully evaluate what is going on. The number of air stones doesn't mean nearly as much as the amount of air your air pump is delivering through them.

Four times an hour is adequate cycling times.

Pictures would be of help.

Oliver

[knvernon]

Okay, I have a 75 gallon, glass rectangular aquarium.
In it is a submersible pump, set up as an inline, with the tube ran to the middle of the tank.
I didnt install a "T" to allow for splash back, because I don't throttle the pump. It simply runs at full force.
My original question was just, is it okay to clean the excess waste off the bottom of the tank by taking the pumps inlet tube and sucking up all of the waste? In turn sending all of the waste into the growbed.

Now i understand the point of everything is to have the bacteria utilize the waste to ultimately create the nitrates for the plants, but I was reading your posts on , oliver, on system setup, design, fish/water ratios etc, and was learning about the heterotrophic bacteria, which is where I was confused, and the original reason why I am asking this question.
Because in your posts you say

" This brings us to the solid fish waste. The good news is that nature provides. In this case nature provides us with another type of bacteria known as heterotrophic bacteria. Heterotrophic bacteria live in the water and attach themselves to any dead organic matter like uneaten fish food, dead plant roots or solid fish waste. Through a process called mineralization, the heterotrophic bacteria convert these leftovers into their component parts, which become nutrients for the plants."

Does this mean I should leave the waste to further build heterotrophic bacteria in the tank or suck the waste up anyways?

I will post pictures once I get the chance

[davidstcldfl]

Hi knvernon, Figuring your blue gill are healthy and eating well, plus you have 28 - 3 to 4 inch blue gill in a 75 gallon tank...the tank won't be 'poo free'. I would expect to see some floating around the bottom of the tank, all the time.

I'm guessing your tank is going down about half way, before the bell siphon kicks in. (?) The water returning to the fish tank should be stirring the FT's water pretty well.

You might/should get more velocity on the siphon's return, if you use an Affnan style bell siphon design. At least that's what I've experianced.

Oliver already mentioned moving your pump into the fish tank. I agree, I think it may/should do a better job of picking up the solids.
I'd normally agree to add a spray bar too. But you said your 'just' getting 4 cycles per hour with your pump.

On the discharge line comming off the pump...try stepping it up to a larger size.
For example, if I have a pump with a 1/2 inch discharge...I'll make the line a 3/4 inch. This lowers the pressure, but you'll get a little more water volume moved....which means you'll get more solids moved per day.
If your using tube, you can use a hose barb coupling, that has 2 different sizes on it.

Hope to see some pictures soon...

[knvernon]

I decided to take out 5 bluegill and put them into my indoor aquarium for now, all of the fish are eating aquaorganic fish food, if anyone has had any testaments about it I'd love to hear them. It was expensive, especially because I bought the 50 lb bag, but I definitely think it was worth it for organic fish food. Now everyone in my house eats organic lol

My pump is submersible pump - it IS in my fish tank, in the corner - BUT, it is set up as inline, meaning I have attached a tube that runs to the MIDDLE of the tank.

My question is very very simple, is it okay to clean the tank by sucking all the poop directly into the growbed?

My water drains from full to about 2/3 full

[davidstcldfl]

The plants are looking nice, and the grow bed looks well built. Nice strong legs to hold all the weight...

My question is very very simple, is it okay to clean the tank by sucking all the poop directly into the growbed?

'Yes'
Give it a try and let us know how well it works...

[JCO]

I'm with David. So did you try it and if so what was the results. Let us know and photos please and try to rotate the this time