Cherry shrimp - Redness

Hi everyone. I have a question for people keeping cherry shrimps. What can you do to make them "redder"? My cherries are mostly pink/light red. Some are totally without colour (big ones).

My cherries are housed in a 2 feet tank, with 3 * 92mm fans. Temp right now is 24 degrees (probably due to the weather now). On warm days, can reach 26+. Feeding them 3 different types of algae/spirilina foods.

I read somewhere that they could turn darker red if the water is harder. Does ceramic rings affect the water's hardness? Cause in my planted tank last time, the water was quite hard and PH was rather high. I never found the cause....Could it be the CRs?

Any help/advice/pointers would be appreciated.

i heard from some bros if ur water condition is right the redness will come out naturally. mayb it's the genes that is not so gd

I sure hope I didn't get a "bad batch". They are reproducing like crazy. It's just that their colours all sux.

haha. cherries reproduce like crazy when the water parameters are good.