Seedlings !

Ok, we got the structure almost done, the water pump is in the bottom tote, and the air pump is tied to the frame, so it is time for something to grow ! As I wanted to start from seeds, I bought some CocoPods. These are compressed Coco discs that expand in the water.

Check my friend's website to see how to handle lettuce seeds as they are tiny tiny.

 The 2-3 first days, it is better to hide the seedlings from light. The lid is great as it keeps the humidity level high (it is quite rare to have super dry weather here in Hong Kong anyhow).

When the seedling are well developped, and the roots are going thru the pods/foam, they are ready to transplant in the netpots.
Seeds don't grow at the same speed, so transplant only the viable ones...

The Typhoon killed my first batch by bending the stems...

7-in-1 water meter... that displays only 3 parameters !

After some research on AliExpress & Taobao for some pH & EC meters, I finally found a unit that was quite cheap and provided pH, EC & Temperature reading. 

I even found a voucher to get 5% on their "original" website

The unit is quite compact and is delivered with an ORP probe, but as there's only one BNC socket, it is either pH or ORP...

And we can't count °F & °C as different features.

The structure

 Instead of using a wood plank and a shelve system from IKEA, I decided to go with a PVC tube frame. We have plenty of little hardware stores in Hong Kong, so sourcing the PVC tubes are easy and close to your home.
You can see on that picture that I have a clear white storage tank... that will help to develop algae :( Black is the way to go.

The only tools you need are a tape meter and a saw.

As the green tote is 42 x 30 x 10, the front bars are 40cm and they are made of 1/2" tubes... The side tubes are 26cm. Now I realised that I should have used 25mm tubes, as metric tubes are easier to source than imperial. 4 Ts per  shelf, 4 Ts for the base, and another set of 4 Ts for a link between the front and the back ladder to keep the structure together.

I found the PVC frame easier to modify and adapt to your needs. For exemple, I started with a single column, and then I thought that I needed an area to put my seedlings, then I added one shelf, and just cut the tubes of the existing frame, and put two T... Voilà !

You'll need tube caps for the feet. Elbows (L) are just for aesthetics...