Ideal Calcium

[Fred]

2 month old system and my lettuce leaves are dying with some necrosis and small black spots on the leaves.  I'm using RO water and slowly supplementing with maxicrop (really darkens my water so I only add a small amount) and RO right.  I decided to get a calcium test since I have quite a few bags of egg shells and crushed oyster.

 

The API test uses the add a drop until the color changes so it's not exact but my water is testing 120-160ppm.

 

Anyone have experience testing their calcium levels?

[Jonathan Kadish NYC AA Chair]

Did you transplant anything into your system or did you plant from seed?

[Jon Paul]

I just bought Glacial Rock Dust.  It has Calcium in it.