Deficiency - what is causing it?

[Bulls]

Ok so quick google search

Canna Ph Down Organic

Canna Organic pH Down is a concentrated Citric acid that can be used to reduce the pH of almost any liquid that it is added to. When growing plants in hydroponics or aeroponics, it is necessary to keep the pH of your nutrient solution within a certain range.


vs.

Canna Ph Down Bloom

Canna pH Down Bloom is a mineral regulator for regulating the ph value of liquids. It contains phosphoric acid, which reduces the pH value of the nutrient solutions in flowering plants. This enables the plants to absorb all nutrients, which are much needed during this period.

compared to what I use now:

Ph Down by Growth Technology.

Ph Down by Growth Technology is a Ph adjuster that contains phosphoric acid which will allow you to adjust the acidity level of your water. Your plants will be able to absorb all of the nutrients given to them; if your plants don't have the correct pH level, they won't be able to absorb certain nutrients.

I guess I will get a bottle of Canna Ph Down Organic and see how it goes with my hard water,
That would be the cheaper alternative for now as I got about 3L of each Canna A&B. Next time I will try Marcus nutrients for hard water,

[kbag]

just a word of warning using the organic one last sentence.

CANNA Organic Acid contains 50% citric acid.

Dosage
Dilute 2 ml concentrate per 10 litre of water (1:5000). Mix well and measure the pH value.
If necessary, repeat the aforementioned until the required degree of acidity is reached.
Recommended pH value pH: 5.2 - 6.4
Warning
Do not mix with pure fertilisers.
Keep away from children.
Minimum storage temperature 5 degrees, store in a dark place.
Bacteria and moulds thrive well on citric acid, and therefore also in the nutrient tank. Care should be taken to refresh the solution in the tank on a regular basis.

http://www.canna-uk.com/ph-series full range here