DWC Beds for a floating raft system

[Kou]

How deep are they?  I heard some say it's 12", while others say it's 18"?  What's the best? 

[Jonathan Kadish NYC AA Chair]

The UVI system, which is the standard to measure against, is 16"

[TCLynx]

I've seen many that are 12 inch deep beds with 8-10 inches of water.  The UVI recommendation of 16" should allow for 12 inches of water.  I have a bed that probably is 18 inches deep with 14-15 inches of water but I'm not floating rafts in it at this time but growing water plants instead.

You can get away with shallower but then you don't get as much free space for water and roots and the aeration doesn't get as much space to mix the water and you don't get the extra stability of having more water in the system.  But shallower containers will be cheaper.

[Kyle Sy]

Hi, just saw the discussion. Have some questions regarding the same topic too.

Is there a maximum or minimum water depth for raft type systems? if there is, what are the pros and cons?

Thanks!

[TCLynx]

A common standard is 12 inches deep.  Many people with get away with less, especially if they provide lots of smaller air stones spread out more and harvest the plants small before the root masses start to cause problems but in general for the widest variety of plants the deeper beds will provide more space for the wider varieties of plants and more water to buffer fluctuations in water quality.