Backyard Aquaponics
A place to discuss aquaponics

So, hello everybody. I've been lurking on these forums for a while now, learning and reading but never asking questions. I'm like that, try and try and eventually after trying, I ask. So here I am, needing advice and to make friends with fellow aquaponics farmers. This is my setup, it has a 65 litre FT with 6 Tilapia (i had 10 but 3 died), seven 2 meter grow pipes that are 3/4 full of water(til my roots get bigger). I also have a small "bio-filter" that I am using to clean my water before it reaches my grow pipes. It's been 7 weeks of cycling; I had 10 fish and I added veggies at the same time just to clean the water and to observe their growth. My PH is at 7.6+; this colored strip, I never can tell for sure. I am getting an API test kit next week so at least I'll be able to test for Ammonia and the like. The ones I have now can check GH, KH, pH, nitrate and nitrite. My nitrite is at 0mg/l and my nitrate at 50+mg/l. My veggies in my system right now seem to be growing but they have a very light green appearance. Is it because of my pH? And also I have read about buffering pH, the media I am using is Aquarium gravel and i realized, only after building, that it'll buffer my pH, it fails the vinegar test. Not all of it, but it seems it contains limestone mixed with it. LECA is impossible to find here, so are net pots so its all very DIY til I can get some money and have those shipped to me. So, do I remove this media from my bio-filter? Or do I use acid to drop my pH? It's a prototype to see if this works here, I would like to start selling my veggies down the road. Thank you and it's good to be here.
Setup
Bio-filter
Sump

Welcome to the Forum Sam87

Looks like the images didn't come through. There are a couple of threads here that should help with figuring out how to post images (The problem probably has to do with sizing the images).

http://www.backyardaquaponics.com/forum/viewforum.php?f=4

Oops! Been long I posted on a forum, here are the images resized. Links to full size;
Bio-Filter
Sump
Setup


Thank you

If the gravel failed the vinegar test then it needs to be removed if you want to have a lower pH. It seems odd that the water pH is only 7.6 normally it would be higher in this situation. I'd redo the test before you decide whether to get rid of these.

Your lettuce plants are light in color because of an iron deficiency. When the pH is high many forms of iron are not available to the plants. You can get around this by using EDDHA iron chelate in the system water (DTPA iron chelate would also work at your current pH) OR you can spray apply most forms of iron which avoids the pH lockout of the system water.

I did another test last night and yes, fizzles everywhere. That pH of 7.6, I'm not sure really, because if i wait a minute plus after i test my water, the pH strip gets darker and darker. It's hard to tell, but I know its between 7.6 and 8.0. I removed the stones and made a small solids filter with two venturi inlets, hope that adds enough oxygen to help bacteria grow. Here is what it looks like, shown below. Also, is this the type of chelated iron to use?
http://www.solgar.com/solgarproducts/ch ... ablets.htm

You'll definitely get growth on the filter and it should help although you may need to clean it fairly often if you aren't getting enough nitrates (the filter will likely release nitrogen if it isn't aerobic and cleaning helps keep them aerobic because the bacterial layers and solids aren't as deep).

On the iron chelate pictured I would say no, it's not what you want. It's possible that you could dissolve it and use it as a spray but I don't know anything about that particular chelate or how easily it dissolves in water or how stable it is. EDIT - Looks like it might be stable between pH 3 and 10 and if this is the case and it can be dissolved then it should work in the system water (might be worth a try unless someone chimes in with a reason not to). Otherwise, you're looking for something like this as your first choice - https://www.amazon.com/Grow-More-6546-Chelate-1-Pound/dp/B00BWE2CUE.

hmm, okay. I don't mind cleaning it every morning if I have to, the sound of the water rushing around my system is very relaxing, I wake up every morning at 6 just to stand next to it
So, chelated iron is expensive here and I can't afford to buy it online for now, so I guess I'll have to manipulate my pH or wait it out. I'd rather do the former, since I have so much gravel, if I ever need to buffer, it'll be easier.

Manipulating the pH could help as long as the food that you are feeding the fish contains enough trace iron. Fish meal which is usually in commercial feeds is a pretty good source of iron. The pH needs to be in the 6.2 to 6.8 range.