Backyard Aquaponics
A place to discuss aquaponics

Thanks to everybody for their advice and suggestions; I have one more immediate concern which is.. whilst we are cycling the system using peeponics we have some tomatoes and a celery in the Dutch buckets they are doing very well, or it seems so... but the leaves of the tomatoes are showing signs of iron deficiency.
My source water is PH 7.8 and I can't easily get hold of iron chelate. I have placed some rusty iron in the sump tank, please don't laugh but I read somewhere that in times gone by wiley gardeners would plant old bits of iron near plants that had iron deficiences.
I'm sure that this problem has happened to lots of people, anybody got any suggestions, please.
Also I have heard that high PH prevents the plants absorbing some minerals and iron, is 7.8 high enough to cause this?

Nails wont provide the soluable form of iron required for plant uptake. You need chelated iron, found in most hardware/plant stores and probably the net.

Here's a chart showing nutrient lockout and pH that might be useful.

http://www.backyardaquaponics.com/infor ... nd-charts/