Processing fish solids in small aquarium aquaponics

[David Palmer]

I've been doing a lot of reading on aquaponics, though most of what I can find is about much larger operations. I'm wondering if some of the same problems apply to smaller aquariums and how people have solved them given limited space.

For an aquarium setup, how do you get rid of fish solids?

I'm using a fountain pump to cycle water through the grow bed. The pump, however, has a small filter that would prevent solids from gumming up the pump. This leaves solids to pile up in the pea gravel.

Here's what I'm thinking are viable options:

1. Put red worms in the pea gravel and make sure the water is well aerated (read that worms take in oxygen through their skin; works fine in water if lots of dissolved oxygen)

2. Get a pump that does not require a filter and add worms to the grow bed (which ones? how to keep cost low?)

3. Purchase an aquarium vacuum and clean the pea gravel manually (least favored method).

4. Add worms to the grow bed. Maybe the solids will decompose enough to go through the fountain pump and end up in the grow bed and the worms will get it.

Note that I have a 26 gallon tank with one 5" goldfish. I'm considering moving to raising koi from fingerlings and selling them when they get to 6-8", or about 0.25 lbs.

What has worked well for you?

[WaterFish22]

For an aquarium setup, how do you get rid of fish solids?

Underwater gravel filter, Reverse flow Power Head Underwater gravel filter, H.O.T Magnum, and 350 Canister Filter, plus my other home made filters on the tank. (You probably don't need all of them but that is just what I use.)

From my experience:

1. Goldfish will not grow as much if they are in a smaller tank there entire life.

2. Smaller tanks have more problems with ammonium, nitrates, and other fish diseases. 

3. Larger tanks that are under stocked take less time to maintain if setup right with a good filter

So small tanks will work but in my mind they are not ideal for keeping fish, if you want to try and save space

try stacking tanks on top of each other. (That's what I'm planing on doing for my setup, since I want more gallons but I don't want to take up the whole basement doing it either.)

[John Cubit]

David,

I am running an aquarium setup. It has been outstanding.  My current issue is with water flow and timing causing rot on certain plants but I have kept the set simple.

I have a 20 gallon aquarium with 475 gph statuary pump.  It has no filter and is made by Tetra.  They do have a filter attachment but it is extra (not included).  I have 4 comet gold fish that were about an inch long 3 months ago and are all over 4" now.  Ammonia etc have all remained consistent once system was fully cycled.

I did not use any gravel or media in the tank.  Bare glass.  The only item added was 3  PVC pipes tied together for the fish to hide and use for nesting.

95% of my solids are pumped to the grow bed.  I vacuum with a hand siphon under the pump, corners and under the shelter once every two weeks and those solids go to a modified milk 1 gallon milk jug.  Takes all of a minute to do.  I dump what was siphoned in to the grow bed and the worms take care of those solids.

I wash the pump once a month and there is minimal buildup, usually around the impeller, another minute task.  The fish will grow.  I have had friends get comets up to 9" in a 20 gallon tank before ponding them.  I have to admit after raising fish as pets for a long time this is the cleanest tank I have seen.  There is a light build up of algae on the walls but you can't notice it unless you touch it and the water is slightly tinted goldish brown, very faint.  I feed them plenty 2x's a day and always toss some chopped celery or cuttings from grow bed chopped up to add to their diets.  My Nitrates have remained steady at 40ppm after it finished cycling, the highest I have seen the ammonia go was .25 usually the morning after cleaning the pump.  pH stays at 7.8 and the temp is constant at 72.  Nitrites stay right at 0.  I also would recommend no direct sunlight and if you use an aquarium light go with one that will control algae as sunlight can enhance the growth of algae.

[David Palmer]

Yes, I understand about the 26 gallon tank.  When my wife rescued the fish, it was in a 10 gallon tank.  The 26 gallon tank upgrade seemed like a good idea at the time.  Once I got the grow bed attached, my attitude towards the fish has changed a lot.  He's no longer smelly and an annoying maintenance problem.  He's now a partner in growing basil.

What I'd prefer is something like Malthus.  But first I need see how this all works with what I have and put together a plan for the larger system.  I really don't want to be cleaning filters (ug).

Maybe I could replace the gravel with sand?  Then the pump can pick up the solids easier... ?

WaterFish22 said:

From my experience:

1. Goldfish will not grow as much if they are in a smaller tank there entire life.

2. Smaller tanks have more problems with ammonium, nitrates, and other fish diseases. 

3. Larger tanks that are under stocked take less time to maintain if setup right with a good filter

[David Palmer]

Why do you need a 475 gph pump?  That should move the entire 20 gallons of FT water in 2.5 minutes. It is encouraging that this is working for you.

I'm estimating that my pump is about 75 gph.  It was in my junk pile of electronics scavenged from an old fountain.  I run it for 30 minutes to flood before switching to a 30 minute drain.

I think I'd prefer sand over bare glass.  Same result, but sand just looks nicer.  The hand siphon every couple weeks sounds better than changing filters. 

I have a friend with a large pond.  He's asking about my goldfish, but we agreed to wait until spring so the poor thing doesn't freeze.  He needs to find a solution to his blue heron problem though...

John Cubit said:

David,

...

I have a 20 gallon aquarium with 475 gph statuary pump.  It has no filter and is made by Tetra.  They do have a filter attachment but it is extra (not included).  I have 4 comet gold fish that were about an inch long 3 months ago and are all over 4" now.  Ammonia etc have all remained consistent once system was fully cycled.

...

[John Cubit]

475 gph pump with a 5 ft lift only yields about 35 gph on this pump.  The pump is only good for 7 ft and that then drops it to 7 gph.  Lift decreases the pumps efficiency for ever foot of lift which leads to less nutrients reaching the bed.  Get the specs for the pump.  Look for head lift numbers for the pump.  Plus I got Home Depot to sell it to me for $25 since the box was open, normally $79.

Pumping by hand takes me only a minute but I have no obstructions, like sand or gravel, I remember when I had a decked out tank it took hours to vacuum cause I would suck out more water that waste cause gravel etc always was in the funnel.

We get the enjoyment out of the fish from them eating out of our hands, and unless you are crawling on the floor or sitting in front of the tank you really can't see em.  Grand Daughter is 2 so she sits there and watches them.