Backyard Aquaponics
A place to discuss aquaponics

You easily have one of the more gorgeous looking systems around! Good job. I believe you are making many on this forum jealous, including myself.

Now my 2 cents on pH:

In my personal opinion you should never worry about dropping your pH in aquaponics even at an 8.2. So long as your feeding enough and you have proper areas for nitrification as well as denitrification to occur. You should be capable of fairly decent growth within your plants even at this high of a pH. Now, this growth will take time to come by. It really wont just happen over night after a system is built. Usually takes upwards of 3-6 months to really have your system fully stabilized and cranking out good loads of nitrates as well as the other micro nutrients that you want to see. After these first few months of operation, your nitrifying bacteria will have hopefully fully colonized your system. At this point they will be turning the ammonia/nitrite over to nitrate so efficiently that they will be producing enough acid within this oxidation reaction to actually make your pH drop. Depending upon how hard your top up water is your pH could actually drop over night far below 7. This large drop can occur due to the fact that these acids eat up all the carbonates within the water thus reducing the buffering capability of your water and in turn creating a less stable system. This is where you will want to start adding potassium bicarbonate and calcium carbonate. I use the carbonates to raise pH because this helps buffer your system from large pH swings. Many out there use hydroxides for this (I use to go that route myself). However, if you are raising your pH with potassium/calcium hydroxide you will find that you very well may have to be adding it daily because your system has no buffering capacity to hold the pH.

Salting for Nitrite spikes:

Your fish will be much happier yes. However, you really do not want these salts in your system. I prefer cycling with fish myself but rarely use salt to mitigate for nitrite toxicity unless 100% required. Your comets should be able to tolerate it for the most part. Other things you can do are water changes as well as just increasing aeration to there tank if a spike occurs.

Iron additions:

Your system is very new and has very little nitrate cycling through it. I believe you have a nitrogen deficiency not an iron deficiency but thats just my personal guess.

I apologize for the mini book! haha I just got excited and want to help and see your system succeed!

-20 something, that's be fun to imagine. I'm in the middle of winter at the moment, and it's 8C outside at the moment, 6C overnight.

Although, I'd love to see snow.

Sorry i can't help with your question, never tried with strawberries through snow. It sounds like they hibernate when it gets too cold, if you keep your GB's full, you might get lucky. Or the frozen water might expand and crush the roots.