Backyard Aquaponics
A place to discuss aquaponics

As you can see I'm having some sort of serious problem here. Any help from the Guru's would be much appreciated.

Perhaps my lights are too close?
Water params are all good, 0 Ammonia, 0 Nitrite, 80 Nitrate, PH sits around 7.4
I thought potassium so dosed the system with Potassium Sulfate at 3 teaspoons. Its a 600gallon system.
Now after looking at some more deficiency pics possibly Magnesium?
I'm shooting in the dark folks, and open to any and all suggestions.
In the grow bed I have Dragon Cayenne's, (the ones in the pics) Thai basil, Aloe, and a whole assortment of various kitchen herbs.

There is definitely some magnesium deficiency going on there. Something else I can't put my finger on though....

Damn, alright, that helps, any suggestions for treating the magnesium deficiency?
I have some epsom salts, Magnesium sulfate USP, suggestions for dosing?

How long ago did you add the Potassium?... I can't see Magnesium deficiciency, but I can definitely see Potassium and Calcium deficiency in the top two pics, and possibly early stages of Iron deficiency in the bottom pic. Have you been supplementing with seaweed extract etc?... you really need to when growing fruiting plants. As you're in the U.S. I would start with Maxicrop (the version that contains Iron) at 30-45ml per 1000, per week.

Maxicrop, liquid seaweed, 0-0-1, Maxicrop Liquid Fish 5-1-1, Grow More Organic Iron Chelate 10%,
Added the potassium 2 days ago.

I thought magnesium deficiencies was when the veins were green, but the rest of the leaves were yellowing off. The leaves in the background on the first picture look identical to that.

I read somewhere that too much light can cause leaf curl like in first picture as well, but I've never used lights, so I'm not 100% sure on that, there are a few other things that can cause leaf curl as well.

You can spray epsom salts on the plants. Try 1 Tablespoon in 1 Gallon, and spray the foliage.

As does Potassium deficiency, and a number of others. In the early stages Potassium and Magnesium deficiency will show almost identical symptoms in most plants, and both show on the older, lower leaves, as both elements are mobile within the plant.

Potassium deficiency is far more common in fruiting plants in AP. I've had Magnesium deficiency only once in over five years and a number of systems, but I've had Potassium deficiency a few times. When my system did have a Magnesium deficiency it showed as similar yellowing to these pics, but with many small dead/necrotic patches between the veins also. It may well be Magnesium deficiency, but I would wait for up to a week after adding the Potassium, to see if there is any improvement, if there isn't, then maybe try Epsom salts.

Too much light and/or heat can cause leaf curl, but the leaves will be perfectly healthy and formed, just rolled up at the edges, and they will unroll after the lights go off each day. Plus, it will be the leaves closer to the light/heat source, so the top leaves. Whereas the top leaves on some of these plants are fine, while leaves lower in the canopy are rolling or cupping. It's the newer leaves on the affected plants in these pics are deformed and hooking down at the tips, and some of the older leaves are cupping, classic symptoms of Calcium deficiency.

There is definitely a Calcium deficiency in this system, and either a Potassium or Magnesium deficiency as well. Potassium and Calcium are probably the two elements most commonly deficient in AP systems, especially when growing flowering/fruiting plants, so I would focus on them first. if you don't have any luck with the yellowing of older leaves, then maybe try the Epsom salts, but I would put them in the tank... and don't try every solution at once, or you'll never figure out which it was that solved the problem.

The support on this forum is amazing, you guys are all very informative and helpful.
I'll wait and see if the potassium does the trick, if not Ill move to the epsom salts, and if still no improvement I'll go after the calcium. I've heard crushed eggshells are a good source? Do I rinse/boil the empty shells or anything first? crush to powder and add to water? Any special prep needed?

We're all still learning Pastryfish, so these chats help us all

The egg shells, you can just put them in pantyhose, and suspend them in the system. I don't believe cooking or not does much difference, I'd leave them raw though.

Just keep an eye on your PH, it'll raise with the egg shells.

I boil my eggshells then sun dry for a while - might be over cautious- though makes me feel less at risk from any pathogens that might have bred in the egg white remains that have sat in the cracked shells for months prior to use.

Don't a fair few people on here use egg whites to try and clear up the water occassionally?

I figured if rocky can gulp down several raw eggs while training, it should be fine in my system.

Think there may be a difference between fresh egg whites and ones that have been sitting in a cracked egg shell for a few months though. I personally would not want to lick those!

I'm trailing half Hangul of ground up egg shells planted around the base at transplanting seedling stage.

Try less flow through growbed, lowering water height, less salt