I found most of my Dyckias do prefer a little bit acid to mild : 5.5 - 7,
alkalinity seem to make them slow down in uptaking fertilizer.

I've been interested in the effect of PH on bromeliads. I'm afraid that there are few options if you keep your plants in a small pot or growing on a tree. It does seem to me that an acid soil will help with iron absorption and add color, but I'm not sure. I've had some good results adding crushed lava rock to the potting mix, maybe because it is high in iron.

What are you using to adjust PH?

Hi im growing Terrestrial Bromeliad (puyas Dyckia and Hechtia) in Clay Pebbles which is an inert (i.e. has no nutritional content) media .feeding with hydroponic nutrients.I use a pH adjustment solutions specially prepared for use in hydroponics. phosphoric acid ph down and potassium hydroxide ph up.

I don't know about Dykia's but my Neo's and Vriesea's all seem to like it acidic.

Since I don't use tap water anymore (ph7.5 kh4) all my broms grow better. The water I use has zero hardness, it is neutral (ph7 kh0) but due to the the low hardness it will react very acidic with the soil I use, since there is no calcium or salt in the water.

I think epiphytic broms in nature are in acidic conditions. Rainwater and leaf litter reacts very acidic.

In my terrarium they root like mad (ph3!). I also use this water when rooting pups and that works much quicker then with the regular soft water I use.

I can imagine spinies have it more alkaline in nature.

Sander