Backyard Aquaponics
A place to discuss aquaponics

Hi Guys,

I just got some Epson Salts and Chelated Iron from the big green shed and can't seem to find out quantities on a forum search. Can anyone refresh my memory on the quantities to use?

I have 400L of growbeds and 1100L of water.

Cheers,
Idzy

Dunno about the Epsom, but the general consensus on Chelated Iron seems to be 1 slightly heaped teaspoon per 1000L.

What are your reasons for the "epsom salts" Idzy...

And what's your pH??

Thx Mr. Damage.

Rupe, this is probably going to sound stupid, but I thought the epsom salts would help, I remember reading they are good and safe. I have just planted some zucchini to give them a go (I realise it's the wrong time to be planting them, but hey I'm having some fun), and they are doing really well, but have some yellowing on the leaves, which I thought could be iron deficiency, but then again, I thought maybe it was something else like magnesium, after talking to the gardening chick at the big green shed.

pH has been off the scale (7.8-8.2) for a while now and I lost quite a few fish over the Christmas period, while I was on holiday. I came back and brought it back down to 7.2 at the moment, but I feel like there is a 'buffer' or whatever pushing it back up.

Any thoughts would be appreciated.

epsom salts are great for Mg but over time can build sulfates in a system without enough water changes. It seems prudent to use them in soil watering or in waste water going to out to drain to waste systems. I use them and other Mg forms as the water around here is very deficient in minerals, so clean the tap water won't even turn on my auto on EC meter. I really don't know yet what for of Mg would be best in an AP system I was working on that until I was rudely interrupted in my research recently. I was testing mag stearate but it seems form reading its not as absorb-able but possibly not harmful buildup wise.

Can chelated iron be added to the water without damage to fish? I have been spraying plants with chelated iron dissolved in water to counteract yellowing leaves and it seems to work well.

Added to the FT or foliar feed are both valid methods. You'll find that you will need much more when added to the water volume to raise and retain @ the preferred 2mg/L. Foliar feed I think is much easier and no test kit is required.

Careful about adding too much iron. I overdid it and turned the water and my goldfish black! I had to do 4 water changes in a 250 gallon ft and now the goldies all have black highlights! Actually they do look pretty cool! I finally did just a knife blade tip for the six beds and the veggies and tomatoes greened right up after a few days. The upside is the black water helped knock off a bunch of algae!

How much did you add, Sails? I think the rule of thumb is around a spoonful per 1000L from memory.