Playing with venturi

In order to save power (off the grid setup), I'm trying to get rid of the air pump. A lot of people in the Aquarium community are using a water pump with a venturi effect. YouTube is full of exemples, so I decided to give a try.

The idea is to insert a small air intake (little tube) in the water flow. To emphasise the effect, you'll need a pressure difference.

A lot of videos and webpages give exemples using a pen body inserted in the PVC tube, or a tiny clear flex tube with an angled cut.

 

Using a T and the tube reducing the section in the 1" water pipe, you create the velocity increase needed for the suction in the air intake.

In this video you can see the pump in action with an adjustable depth clear tube. It really depends on your water flow.

Sump pump & filter

To beat the heat  & algae problem, I was looking for a solution or a least a way to minimise the invasion.

Step 1: How others do ?

Being in Hong Kong also has its benefit: you have restaurants with fish tanks all around the place, and they also have to beat the heat & algae problem. So by having a look at their setup I found out that they have a quite simple setup including a mechanical filter and a UV lamp for most of them. Nothing fancy, nothing costly. And for sure, they renew the water quite often, which is impossible for a cost effective hydroponic setup.

Step 2: Internet is your friend (again)

After some research on YouTube & other blogs about aquariums (these guys have years of research ahead, and the DIY community is just massive), I found some interesting & cheap setups based on layer filters and also inline filters for pumps.

Step 3: The inline pump filter

First, the pump I used is 12V pump, placed in the bottom of the sump. But I secured the thing with the filter you can see in the video. It is composed of a cheap 25cl plastic bottle with the bottom cut, and the cap drilled to fit your pump intake. Then you add some water cleaners (from Fish market), and balls (in the aquarium/aquaponics setups they are supposed to host bacteria to consume the fish poop and turn it to nitrates), and a layer of cotton style foam (again, Fish market).
The pump by itself can clean your tank in 30mn... but the foam get clogged fast.

Step 4: The first layer

First, the pump I used is 12V pump, placed in the bottom of the bucket. It will take the water from the bottom, so you need room around. The first layer is composed of plastic balls to have a good flow of water.

Step 5: The second layer

You need to filter, as the first layer is just for the flow, the second has to handle some debris. So I went with cheap loofa from a local 1$ bazar. I took 10 of them. Some are free, some are left as a string.

Step 6: The last layer

All the sumps will go thru this layer, so you'll need to keep most of the crap here. It is based on floss filler. In fact, this is an experience, so I may add one coarse layer on top of this one. The floss filler comes from the Fish Market. You can buy bulk packs for 40-60 HK$.

Step 4: Final step

The pump is on the bottom, so I had to connect the flex tube to the 1/2" PVC tube that comes out from the top. The valve you see is just to drain the lower part, when it's charged with residues.

Heat !

Not much posts for a while, because now in Hong Kong it's really hot and everything almost died, except chilies...

 

As a lot plants died with the heat and I had to handle a lot of seedlings, I thought I could try a regular grow bed with pebbles so I can plant & remove dead plants easily.

 

I also wanted to give a try to cucumbers. It grows fast ! But then I got worried that there were no fruits and all the flower were blooming and then dropped and cover the floor... In fact, that's normal as Cucumber grow male flowers at the beginning and no female flowers. So after 3 weeks I finally got the first female flowers that can grow cucumbers.
Unfortunately, I got hit by aphids & whiteflies. They also jumped on the chilies & basil :( I tried soap water, bleach water, but the whole plant was sucked down but these nasty bugs. I couldn't find flypaper in time, and the whole plant died while we were away in June.

 

Now it's summer time with max temperature, typhoons, storms and all the nice things that makes expats fly away, but I'm still here. The only thing that grows now are the chilies, basil (not much anymore), chives.
My friends from Amazing Green Hydroponics & Mizutech gave me Kale seedling but they never grew and died :( It's just too hot outdoor. They grow them well in Kwai Chung but they're indoor.