Backyard Aquaponics
A place to discuss aquaponics

Well the light is not too bright tbh, its reflected downwards onto the plants. And the noise is just the siphon return; gushing water for 20-40 secs every 10 mins or so. The pumps don't make much whirring noise etc. Also, its kind of tucked away in an alcove of the room. It's ok here when you're used to it (actually quite relaxing), but I wouldn't have it in my bedroom, unless it was a quieter system.

My fish are happy and the mint is too (still plotting world domination despite me setting it back with a few mojito nights!), but my lettuces appear to be suffering some sort of deficiency:

Growth of young plants looks healthy and vigorous, but once they reach a certain size, of an orange roughly, and with very tightly compact heads, they stop growing altogether. I don't know what deficiency(ies) is/are, but I guess its not surprising given that the system is young and it doesn't make the solid waste available to the plants.

My pump circulates water, but solids remain in the FT. I guess this is where the nutes (that my plants are deficient in) are contained. My question is what should I do?

1. Make no changes and keep replanting new starter lettuces, perhaps the solid waste will eventually disolve into the water and find its way to GB...

2. Siphon off solid waste and throw it away/feed it to plants in dirt, and plant more mint or watercress or something that works well as the system is

3. Somehow siphon off the solid waste and feed it to the plants in GB without it flowing back into FT and soiling the water and possibly harming the fish...

I would like to be able to grow lettuces... would disturbing solid waste and having it suspended in the water be dangerous for the fish?..

Any thoughts or advice would be greatly appreciated!

I'm not usually a fan of media on the bottom of the fish tank because it accumulates solids and can cause problems with anoxic zones within the tank. Having said this you might be able to use this media to your advantage with an under gravel filter which is designed to flow water down through the gravel and perform nitrification. If you put one of these in and made certain it was maintained (to prevent too much solids buildup and denitrification) and the water was well oxygenated (to encourage nitrification), you'd be adding additional biofiltration to your setup. You'd still be getting some solids pumped up to the grow bed for break down while you allowed a lot of the solids to break down on the bottom of the tank instead.

There are other possible solutions mostly having to do with water movement and filtration options to do a better job of collecting solids.

I do like the idea of using under gravel filtration, perhaps I'll design and install it into the system someday, but it will be a fairly big job, so it'll have to wait till I've got a lot of spare time and motivation!

Anyway, I've strung up a large bottle next to my tank connected by a water bridge, my system is sumpless and therefore has a relatively small fluctuation in water level in the fish tank, which means that there is a slight and gentle water exchange between the bottle and the tank, water flows very slowly from the bottle into the tank, and back into the bottle more quickly when the siphon dumps.

The idea is to have a daphnia colony in the bottle, and the water exchange will provide the daphnia with sufficiently oxygenated water, and will release a few daphnia into the tank over time providing fish with live food. I have been trialling it for a while, and so far the daphnia have not been able to get established, perhaps because I haven't introduced enough at once to start off, or because the rate of exchange is too great for them keep up with reproduction, which is probably the case as they need green water etc to proliferate, and this will not remain in the bottle at high enough concentrations for enough time.

However, I am planning to trial the same design with gammarus, which I can collect from the wild next time we visit my gf's village in the countryside. I think it will work better with gammarus as they eat rotting wood and leaves etc which can sit there in the bottom of the bottle.

Has anyone tried this? Reckon it will/could work?

here is a link to a setup a guy did on another forum I'm on for feeding baby brine shrimp. It worked out pretty awesome (might be a couple of revisions in the thread before he got it working awesome, but if you follow through to the end of the thread you'll see the steps he took to fine tune it) - but it was not intended to be a long term breeding tank... need a larger tank if you think you are going to do that... would be better to breed them in a separate tank then just add them to the feeder bottle as they run low.

http://www.thereeftank.com/forums/f76/b ... 12169.html

Nice little system going on!

I would agree with scotty435 with not having a substrate in a system with the sole purpose of producing is better. But in the home, its nice to have something nice to look at. So I do have a substrate in my system, and they do collect solids. From time to time (couple months) go at it with a traditional substrate suction cleaner thingy you find in any aquarium maintenance setup. Not a fun job, but I think its worth the chore as it looks better in my living room.

I do have an idea to have a substrate and not have to clean it I've been pondering on. I'm not worried about patents, but I would like to build and test it out for myself first before I share the concept. Unfortunately I don't have the time in the next while to do it but I hope to have it build withing a couple of years and I'll be sharing that process via my YouTube channel blog.

Yeah I actually made a siphon hoover device attaching a hose to a plastic bottle and hoovered my tank out JUST yesterday, with the intention of adding the solids to the GB slowly, so that they would have time to settle down. The device I made worked very well, but unfortunately I collected the water siphoning back into FT from GB, and it was full of solid waste... Woops, when I built the system I designed the bell siphon intake to be at base level, even lower in fact as the bell slots into an indented square, so a great deal of the solids that enter the GB are sucked off the bottom and recirculated until they settle in the FT!

The easiest solution I can see is modifying the media guard so that water enters the siphon chamber through holes an inch or two up from the GB floor, but I'm not sure it will be effective as the guard will have to be totally flush with GB floor, which doesn't seem practical. This would be a bit of an effort, and rebuilding the whole siphon even more so. Alternatively I could just get rid of solids and stick them in compost for soil plants, and stick with leafy greens etc in the AP. But it seems like shame I would like to get the benefits of a fuller nutrient spectrum.

I would also like to install under-gravel filtration at some point, standard aquarium design with air lift in a tube drawing water through gravel, but with an attachment on the tube for a hose in order to siphon out the built up solids. But funds are tight atm.

The daphnia project is on hold now after an incident where the plastic handle the bottle was hanging from snapped, and several litres of FT water were siphoned on to my living room floor!

Chris, crack on with your design! Its satisfying when inventions turn out successful! And let us know how it works etc if it does! lol

Solids are something you want some of, but they break down to slowly and can overburden the system. So trying to remove most of them is a good idea. Large AQ systems incorporate a device of the sorts to remove them. In the long haul, your still going to need to clean out your media grow beds (couple to few years) with a good solid removal system.

In your case, without a sum tank, you might have to tolerate the removal of waste in the same way you would with an aquarium setup. Its unfortunate, because I think people, myself included, get sold that the plants/grow bed do a perfect job at removing waste. But in the end, there still a problem that needs to be addressed.

Here's and interesting read for ya:

http://www.microponics.net.au/microponi ... id-wastes/

Yeah, it's an interesting read, a bit one-sided I would say though. While it does lay down the various benefits of the separation and controlling of solid wastes, there are plenty of people who have very successful systems and let mineralisation happen in their GBs. This is an on-going debate, I think both approaches can work fine. I guess the main difference is the type of maintenance involved with each ie, in GB mineralisation involves cleaning out GBs (big job) every couple of years etc, and separate mineralisation involves regular maintenance but little effort.

For my own little home-system I think I'll continue to vacuum up the solids and re-introduce them to the GB, if I do this slowly enough, as I found out yesterday, they stay settled in the upper strata of media, and there they should break down bit by bit.

For future long-term large-scale projects I think I would use the in GB mineralisation approach for outdoor cold-climate systems; when plants die off in winter I would clean out GBs. And for indoor systems with no seasonality I would use separation of solids approach.

One question that still bugs me though... When off-line mineralisation is finished, the nutrient rich water is reintroduced, and the "sludge" is discarded... what actually is that "sludge"? What does it contain?

Agreed. Another factor to consider is what your growing too. If its a raft system growing lettuces, then a whirl fitter would be great. If your growing tomatoes, then you might want to give the microbes more time to break down the solids and put those minerals into the system for flower/fruiting plants. But, that's what makes sence to me on paper, I have not actually put that into practice myself.

I would take a gander and say that sludge is mostly minerals. Sure there are some compounds, but I'd say the bulk of the value comes from the concentration of the primary plant nutrients, secondary plant nutrients, and micro-nutrients.

Been a while so though it was time for an update.



Had another couple of cabbages a while back but unfortunately i tried to make sauerkraut, and my liberal hand with the salt resulted in an inedible mushy substance. Will stick this one in a stir-fry instead!

Harvested a couple of small lettuces last week to make room for some rocket and basil which is germinating (hopefully). Will use leeks when they are still small.



Have gone with hardy small temperate/tropicals instead of goldfish. The goldfish died off unfortunately due to health issues related in the first instance to solids build up (couldn't keep up with inefficient siphon hoovering for 6 fish). Then, after replacing with a single goldfish and some minnows a death in the family meant extended time away from the flat, and sadly long-term lack of regular feeding took its toll on the goldfish, who was too slow to survive by feeding on the minnows. Those 5 minnows are are part of the current population.

I am intending to introduce gammarus pulex to further break down fish solids and increase biomass providing more nutrition. A lone survivor from the last lot may still be living under a rock, but I'll need to provide more hiding places before the next introduction for them to become established. This will also provide an alternative food source for fish while we are away from the flat.

Also trying to cultivate a meaningful quantity of daphnia with limited resources to supplement feed with some live protein, and entertainment, as my nearby source of mosquito larvae looks to have disappeared for the winter.




Bought another 90 degree piece and put another elbow on my siphon drain. This allows for adjustment of the angle of the final down-tube, and now siphon initiates more reliably and is less noisy. Happy with the result.


The system is a year and a half old now, and I'm pretty happy with where its at. I think it has reached a decent equilibrium... fish and plants seem happy.