Alkalinity problem. Help!

[Brownic]

Calcium : 450ppm(salifert)
Alkalinity:87ppm (ph titration upto 4.2)
Ph:8.3
For increasing the alkalinity, I dosed baked baking soda.
Now ph increased to 8.5
alkalinity 105 ppm.
please guide me.

[bertoni]

You can dose plain baking soda. It'll have only a tiny effect on pH. The pH increase from baked baking soda is very temporary, in any case.

[Brownic]

Thanks a lot.
I will wait till ph comes 8.3 and then dose baking soda

[bnumair]

Thanks a lot.
I will wait till ph comes 8.3 and then dose baking soda

you can always use regular baking soda (sodium bicarbonate) which will have a low pH effect and is all temporary but in return will increase alk.

[tmz]

87ppm(1.74 meq/l /4.8 dkh)is very low ;hard to understand it in the context of the other numbers. .How are you measuring it? What t is the specific gravity ( salinity)?

[Brownic]

salinity 1.024(swing arm hydrometer), for alkalinity check I used N/10 hcl solution and put into the formula
0.87ml hcl *0.1*50000/50ml sample.
Currently 105ppm alkalinity
ph 8.4
salinity 1.024
calcium 460ppm