Well, I like in the middle of "citrus country". My soil pH is about 7.0 (6.9 to 7.1 depending on where I test.) I don't think it's the pH, or we'd never have been able to grow millions of dollars of citrus here in the coastal S. California area for last 130 years or so. And, changing the pH in a pot is one thing. Trying to adjust the pH in a hole in the ground is difficult to maintain. Unless pumellos are overly sensitive to pH, and I am not aware of that, then I think it's something else. What is odd to me is that the Oroblanco and Melogold are also struggling. These two varieties were developed specifically for my area. I see plenty of mature ones growing very well here.

Now that your tree is in a container, we wish the tree a prosperous future. After all the tree has a RN looking after it. On another note, In my opinion, and the opinion of many, I believe Super Thrive is a complete waste of money. An absolute worthless product. But on the other hand it will not do any harm. - Millet (174 BO-)

Thanks for the words of encouragement, Millet. I think that's why I feel so bad. I'm an RN and in the business of helping people get well. Not in killing things, lol!! And I agree, SuperThrive is probably a waste of time, but I had a bottle, so what the heck. I might also try topping the pot with a little soil sulfur and compost. Can't hurt.

well, sometimes nature is a mistery ...

as you are tryin everything, I would test nevertheless the ph-value in pot and give a liquid fertilizer with lots of minerals and trace elements.

I would let the roots re-establish before putting a whole lot of fertilizer on the tree.

The roots don´t work .. so I would try to help them ...

Laaz I'm using a lower N fertilizer to try to promote some root growth.

From what I remember, B vitamin helps with root growth.

Also I don't know if you're aware of the willow... http://deepgreenpermaculture.com/diy-instructions/home-made-plant-rooting-hormone-willow-water/

When looking at the leaves of Hooserquilt's tree, it is showing the signs of an iron deficiency, about as bad as I have ever seen. Normally, when a citrus tree has a deficiency of iron it show up on only the new leaves. To have the entire tree showing such symptoms it would have to be a quite bad situation.
Good pummelo cultivation requires a LOT of fertilizer nutrition. Pummelos are normally grown in warm countries like Thailand, where commercially a tree would receive 6 fertilizer applications per year (once every two months) totaling 5 kg of a complete fertilizer per tree per year, PLUS a foliar spray with each new flush. That is a LOT of nutrition Such a cultivation practice would have to be adapted to California's climate, which have winter temperatures lower then many tropical locations, still the nutrition levels would be elevated.- Millet

Iron or other minerals and trace elements defiency ...
Most time a whole number is lacking, not only iron.

Therefore I suggested a liquid fertilizers with lot of minerals and trace elements ...

Thanks Laaz. Think you can do this with an aspirin too, if my memory serves me. SuperThrive is loaded with B vits (you can tell By the smell). But, I've heard conflicting stuff about it. Won't hurt, so I'm trying it. Will check omit the link, thanks

It's not that, Millet. I fertilize every 2 months. I use high quality citrus fertilizer with high levels of micros and humic acid I've also applied FST. And several foliar apps of Grow Power Citrus Growers Blend. All my other citrus are dark green. My pummelos and pummelo hybrids appear to have something systemic going on. And it's not just me but my two neighbors as well. One is very experienced and a doctor who spends time doing significant research. We are all a little stymied to be honest.

might be a desease then ...

Patty, sadly a long time ago RN's stopped giving nightly back rubs to their sick patients. Perhaps that might be the exact problem with your tree. - Millet

Oh, this must the reason, Millet. And I sure remember those backrubs. Wish we could talk care of patients like we used to. Maybe a nice backrub and little side down, bedside chat with my poor little tree will perk it back up! Crossing my fingers.