If you will be introducing air along with your nutes next time, I would suggest designing your 'root zone area' to cope with possible increased pressure in your root zone by adding a one-way venting valve of some sort (even a rubber flap over the end of a pipe would do).
Congratulations on getting a couple of house shredders We have a part-time cat who likes to leave us mice.
At my end, I have spent all day renewing every brass fitting in my system, and all pumps which have a cast iron casing. During this process, I noticed my PH had gone down to 0.7, just a little too low. After a small panic involving just dumping as much tap water as I could in the tank whilst pumping out as much as I could but strangely to no effect, I noticed I had dropped just a few drops of water onto the BNC connector for my PH probe...
So I also have a new leaf issue, one I have seen before.
The last time I saw this was when my friend who is a plumber made me some shiny bespoke pipework for my system. It looked lovely. Soldered copper joints, taps, and lots of shiny copper tubing.
Which was just before I found out copper causes your plants to go bright yellow.
So I think I have two issues. One is that the iron in the pump casings has corroded and is leaching iron into the water, giving me a potassium deficiency later in flower and the other is that the brass valves I have on each outlet are corroded and are leaching copper into the water making younger plants go yellow. I noticed it a few cycles ago but thought it was a humidity issue, but when I was in Portugal I had an issue and all the PH down was pumped into my tank, taking it down to 2PH, and I think this has corroded pumps, valves etc.
So they are all gone now. I now have two Grundfos UPS3 pumps (which are a bit more powerful and cheaper as a bonus) and new valves throughout. I will use these for the next year or so and source stainless steel alternatives.
Fingers crossed I should hopefully see them perk up in the next few days. I have been foliar feeding to try and get some nutes into them so they can make more roots.
The mind boggles what they mean by this