Backyard Aquaponics
A place to discuss aquaponics

Just thought I'd share my small indoor system.

Growbed, fish tank and sump are each 30 gallon cement mixing tubs.

Standpipe in fish tank keeps water level at a constant 6-7 inches.

Im using coco chips as my grow media, which I love so far! Along with coco coir as the upper layer. (makes sowing seeds easier, and creates a better light and moisture barrier) SO far I've had a 100% germination rate with every single seed I have planted directly into the coco. (the packages on the heirloom seeds I bought stated around an 80% germination rate)

Because of the lighting, it's difficult to see the correct coloring of the system, but the rust colored coco coir looks gorgeous against the lush green vegetation. Looks almost like a pine forest floor.

I've got a handful of feeder goldfish that love the dark water caused by the coco. (It looks exactly like the Wisconsin river, which is stained brown from willow roots)

The only drawback is that the darkness of the water makes it difficult to see the fish.

Growbed takes ~5 minutes to fill, stays that way for 10 more minutes, then takes 5 minutes to drain. It does so every hour.

Im using an in-line agricultural sprayer filter to remove the gross particulate, of which there is very little.

Im growing spinach, butter-crunch lettuce, rainbow chard, lemon basil, sugar snap peas and radishes. Im curious to see how the radishes like the coco.

Does the surface of the coco coir stay dry? Sounds like an interesting experiment Please keep us posted.
The tinted water might make some of the water test readings a little difficult to read.

The top 1/2 inch or so remains bone dry (water level comes up to an inch below the surface of the coco). Even at night when the light is off.

Yeah, I forgot to mention the difficulty of test readings. I use a digital meter for pH. And the ammonia/nitrite/nitrate sampling kit that I use requires water blanks for reference, which makes up for the water coloring.

Cool, could you share info about the water test kits you are using, could be helpful to others thinking about using coco products as grow media.

I'm not sure of the brand or even how to order the testing supplies. I can check tomorrow with my maintenance guy. It's part of a commercial water testing system for public water supplies.

Just wondering how things are going with the coconut chips and coir- I've been thinking of it as an alternative to cinder, and we have lots of the stuff laying around in Hawaii! Mainly, I'm concerned with the water staining, did it ever decrease, and do you think aggressive pre-soaking and washing would help eliminate that issue? Many thanks-- Shawn

At the moment that would be my primary concern with it, the staining of the water. Not being able to see the fish well or tell if the bottom of the tank is staying clean can be a huge issue in larger systems. In that small system with such a shallow fish tank I'm sure it's probably fine.

I ended up soaking and rinsing the coir for about 2 days (soak in warm, rinse in cool) which helped significantly, but the staining is still a bit of a problem. Adding activated carbon to my inline mechanical filter also helped significantly. I added a light colored gravel, and now I can see all my fish, but visibility is still significantly obscured.

One other problem that I ran into was flood drain times. Coco holds a lot of moisture, so flooding too much can cause root rot.

My solution was to build a separate biofilter (5 gallon bucked filled with assorted media, fills from the top, drains out the bottom), which runs 15 on/ 15 off constantly. Then I can flood the growbed just once a day, or up to 3 times a day depending on the plant needs at the time.

For me, coco has worked best with drain to waste, which I use for growing large tomato plants.

About sums it up from my experience as well... no good for flood & drain... OK for slow drip, which can have bio-film/algae build up & blockage... or a very intermittant, maybe once a day watering...

Probably easiest to use it in a periodically flooded wicking bed...

Bummerz. Oh well, it was starting to sound perfect except for the staining and root rot. Guess I'll stick to cinder, but it's just such a hassle to work with...thanks for the update.

The root rot has not been a problem at all since I started flooding less frequently.

With larger plants like tomatoes I flood as much as 6x a day. 1x only for sprouts, and 2x at the most for leafy greens when they are larger