DIY Bell Siphon for Ebb and Flow Aquaponics with 75 gallon Aquarium

I had a rough week this last week, so I decided I needed to build something. So I built a bell siphon for an ebb and flow grow bed (also called Flood and Drain grow bed_ for the 75 gallon fish tank in the living room. This will allow me to grow plants using the fish water. This is pretty cool, as it means that the plants will remove the nitrate buildup which is the primary reason people need to do partial water changed in their aquariums.

My 75 gallon aquarium in the living room before I added the  aquaponics component to it.
My 75 gallon aquarium in the living room before I added the aquaponics component to it.

The whole thing will be completely automated and cost me less then $50 including buying tools and leaves me with lots of spare parts. 3 pieces of 4 foot PVC pipe with only about 6 inches cut off of each, so I have enough of this to make half a dozen more if I wanted.

A bell siphon is a passive autosiphon device that allows a continuous flow of water into a container to periodically be drained completely out of the container. This is good because it allows me to have my Eheim aquarium canister filter output into the grow bed, and the bell siphon will flush the bed regularly, aerating the plant roots.

To start, I assembled a drain out of plumbing PVC parts. This consists of a stand pipe to go inside the aquarium, 2 fittings to work as a bulkhead nipple, and an offset to route the water around the aquarium lid into the drain tube.

Showing where the tub will go.
Showing where the tub will go.

My wife let me buy the parts and take over the 75 gallon aquarium in the living room with my plants. She had it decorated really nicely, but my plant stand was evicted from its spot to make space in the baby room. They needed a place to go, and I used this as an excuse to work on the aquaponics setup.

Katie and Bella Supervising
Katie and Bella Supervising

I started fiddling with the pieces I had bought and realized that I didn’t get all the right pieces I wanted, but I had gotten enough to make it work.

The bottom half of the bulkhead and the 90 degree angle.
The bottom half of the bulkhead and the 90 degree angle. The angle will provide the offset to go around the tank lid.
A bit of glue oozing into the PVC joint.
A bit of glue oozing into the joint. This needs to be cleaned out to provide less water flow resistance.

I used an antique brace with an adjustable size bit to cut the hole in the plastic. Basically, the edge of the bit would score the plastic. It worked great, except for the plastic cracking.  I siliconed it up, but, to my great annoyance, the silicone was old and didn’t set. I had to clean it off and go get a new tube and try again.

Cracked grow bed bottom
Oohps! I cracked the bottom of the grow bed. No worries, a bit of silicone will fix it right up!

After two days of futzing with this thing, I finally got a dried silicone seal around the stand pipe and over the crack. The grow bed will sit on top of my 75 gallon aquarium so I designed the drain to offset around the aquarium lid. No drilling holes in the lid… yet…

The stand pipe drain for the ebb and flow hydroponics grow bed.
The stand pipe drain assembled and ready to seal in place with silicone

I then made the bell siphon which sets over the stand pipe. I again used my brace and a smaller bit to drill holes in the 3″ PVC pipe. This made it much easier to cut with the PVC cutters I had bought. The 3 inch was just to thick for me to cut otherwise.

PVC holes drilled with a brace and bit
Using a brace and bit to drill holes in the PVC where I will cut it to make the bell siphon.
The bottom of the bell siphon
The notches in the bottom of the bell siphon allows water to flow in easily.

A slight design flaw (um, the drain) left me with a grow bed that wouldn’t sit on the aquarium stand lid. A bit of scrounging around, and I found a plastic crate that I am using. The grow bed sits on the crate, which leaves enough room underneath for the drain to fit. It looks a little precarious, and I would like it to be the 4-5 inches lower, but it works for now.

The aquaponics ebb and flow growbed sitting on the aquarium light hood
The grow bed sitting on the aquarium light hood.
Aquarium filter filling the aquaponics ebb and flow growbed on top of the light hood
The canister filter has nearly filled the growbed. The water height is limited by the height of the stand pipe.
The bell siphon sitting on top of the stand pipe
The bell siphon sitting on top of the stand pipe. This is where the magic happens.
The bell siphon sitting on top of the stand pipe
Looking at the whole bell siphon drain.
Threaded drain gives me options in the future.
The threaded bottom allows me to potentially change how I drain this grow bed if I wanted to.


The growbed is continuously filled, and intermittently dumps into the aquarium below.

The drain in the aquarium
The water from the grow bed returns back to the aquarium here. The grow bed is still filling in this photo.
Bell Siphon draining into the aquarium
Bell Siphon draining into the aquarium. See all the water flowing out?

I placed my plants around the grow bed and the few items that where required to stay on the tank stand – family photos. I think it looks pretty good in the house! I hope to grow lettuces and herbs such as basil in it. Things that we eat regularly and are best fresh.

Indoor aquaponics setup on top of a fish tank
I only have desk lights with CFL bulbs right now. I think it looks pretty good!
Living Room Aquaponics in an aquarium
The tank looks good with the aquaponics on top!
I am pretty sure I can’t feed everybody in the photos… yet…



You can visit to see this same siphon and growbed in use on an expanded system.

A busy week


It’s been a busy week this week. My daughter was born on Tuesday. She’s healthy. More about her coming soon. I ought to be able to write a blog post about that experience soon.

Friends and family have been calling and visiting. A good buddy actually just left and my parents are here too – already in bed. I am the last one up.

My parent’s and I visited the house I am trying to buy. Short sales suck for how long they can take. It’s looking good for the end of the month to move forward. I may be moving come June.

You may have noticed a totally new look for this blog. The migration to wordpress is coming along. I may need to recatagorize some posts as WP has both categories and tags. I used an auto-tagging tool to tag all the previous 500+ blog posts with less the stellar results. So I will need to manually tag high traffic pages soon so the related posts plugin presents better related pages.

I have to work tommorrow. Migrating websites to a new server. Best done on a slow day traffic wise. Sucks to work on a day off, but it keeps me in a job.

I am writing this post on my android phone which is relatively painless. There is an app for WordPress. I miss the live spellcheck, which sucks as I have lousy spelling. I will need to make a point of coming back and editing for spelling tommorrow. I put in a mobile template for the blog that seems to work well.

Burnt out florescent lamp

The living room light burnt out last week. This weekend, I picked up a new 3-way bulb for it. When I went to take the old one out, look what I found.

It looks a we-bit shot. Broken. I wonder if this is a fire hazard?

Cutting out Wedding Invatations

So, this week I have been working on the wedding invitations.
Katie and I are arguing over who gets to make the invitations. We both love doing this craft type stuff. Being taht I have posssions of the printed peices, and posession is 9/10ths of the law, I get to do more then she does. I do have to send half to her for her to finish though.
Here is my stack of printed invites prior to being cut. I am cutting them on my Fiskers rotary cutter with the deckle blade.

I have a few of them cut here. I did mess up on one, you can see it on the side there. 10 1/4, 5 5/8, 5 3/8, rotate paper, 4 1/2. Those are my cuts. That just trims the long sides.

Here is my completed stack of invites. Now I just need to to trim the top and bottoms. Katie did let me do this job all by myself. It isn’t so much fun.

I am having trouble finding the black cardstock that we want for the background sheet. I am going to go check out a scrapbooking store this weekend.

If I can’t find what I am looking for, I am going to try to dye some of the cardstock I have black. I am thinking that letting it dry on crumpled up seran wrap will give me some neat textures. I will play with it.

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