I have a product that might well help you guys with raising pH in hydro, well coco anyway,
Bio ChitoGro, its a liquid is a rich source of chitosan, the chitin- derived carbohydrate that is an essential component of natural soil humus but is often absent from heavily managed or sterile soils pH4-5
BioChitoGro stimulates a wide range of beneficial metabolic effects in both plants
and soil microbiology, especially soil fungi. Bio ChitoGro promotes rapid and dense root growth and allows the plant to maximise its rate of recovery after nematode damage or pathogen attack. Bio ChitoGro increases the efficiency of applied fertilisers by chelating nutrients in the growing media and also helps to maintain an acid pH in soil and growing media.
Added tip:
Applied as a foliar spray 5-10 days before frosts are due Bio ChitoGro may improve frost tolerance in less hardy plants.
1L will make about 1500L of solution and its £159.60 for 5L