what is this defficiency

[master3z]

new leaves on this plant is turning white..

sagitarria subulata

i dose potassium nitrate,magnesium sulphate and potassium phosphate, 50% water change per week.

pressurized co2 diffuse via glass diffuser,. tank size 70gal

light
2x24W t5
1x30W t8
4x18W cfl

 

[jazjac]

It may not be a defficiency but rather too much CO2. If you know your CO2 levels are correct then I may be wrong.

 

[Ady34]

Hi,
do you dose trace fertilisers at all? Could be this if not.
Also your lighting sounds very excessive if they are not timed to be on at different times of the day. Im almost convinced that if all that light is on all the time then you will be low on c02 as light is the driving force behind c02 uptake. I can see you have snails in your tank and these can be gassed with high c02, so based on this im presuming its not above 30ppm in which case i think the 2x t5 24w would suffice. Of course as said i am presuming some things and you may run the lights seperately for sunset/sunrise bursts.

It may not be a defficiency but rather too much CO2. If you know your CO2 levels are correct then I may be wrong.

Never heard of too much c02 before....with respect to plant deficiencies.
Id reduce the lighting and dose chelated trace (micro) fertilisers alongside your macro ferts, available from many of the forum sponsors.
Cheerio.

***EDIT*** Just re read your stats and its a 70g tank not 70 l as i read initially. In which case it maybe just down to lack of trace fertilisers.