DSB and problems whit nitrate dosage

[Gimmy770]

Hi I have a problem with the dsb and with the dosage of nitrate after about 14 days from the beginning of the nitrate (nano3), a strange reaction is created in the tank that leads to the burning of many apicals of coral sps.

I tried to use also potassium nitrate (kno3) but the result is the same.
I have also tested on other 3 dsb and precisely after about 10/14 update the apical of the corals begin to burn.

Unfortunately I have nitrates to zero and I can not in any way increase them. the dosages were such to maintain the value of fixed nitrate throughout the day I have not exaggerated, but I used the maintenance dose for my tank.
Can someone explain to me this kind of reaction that happens to be able to burn the apical ones?
Thank you.

 

[GoVols]

Just asking...

Where do you keep your reef's alkalinity?

 

[Gimmy770]

Just asking...

Where do you keep your reef's alkalinity?

7,5/8

 

[Randy Holmes-Farley]

Are you monitoring phosphate? Maybe you dropped it too low via the nitrate dosing.

 

[Gimmy770]

Are you monitoring phosphate? Maybe you dropped it too low via the nitrate dosing.

po4 are always very close to zero if not zero

I use an elos hr test and a hanna phosphorimeter

elos test 0 / 0.024
hanna phosphorimeter 0

 

[Randy Holmes-Farley]

Which Hanna?

Phosphate may be too low.

 

[Gimmy770]

Which Hanna?

Phosphate may be too low.

Hanna Hi-736


during the dosage period of no3 every 3/4 days I dosed a bit of potassium phosphate