Mixing salt and resulting ph

[Joel j]

Hello all, I almost have everything I need to set up my first salt water tank.
I have questions about salt mix and ph though.
I'm coming from shrimp only tanks where I mix minerals to a gh of 4-5 and 0 kh and then in the tank there is soil that buffers the ph to 5.5-6.
My question is when mixing salt does that give the proper ph as well? I am using caribsea fiji pink sand. Will that buffer the salt mix to the right ph in the tank?
I've watched a lot of videos and read another of articles but have found nothing about the ph of freshly mixed salt water. Also I assume that the salt mix will have the right kh and as far as I can figure out gh doesn't matter.

 

[crazyfishmom]

There are many salt mixes out there and they all have different targets for dKh, calcium, magnesium, etc. freshly mixed saltwater normally mixes to a ph of 8.3 but as soon as in the tank it can shift significantly. CO2 in your home will have the biggest impact on pH most of the time.

 

[Joel j]

There are many salt mixes out there and they all have different targets for dKh, calcium, magnesium, etc. freshly mixed saltwater normally mixes to a ph of 8.3 but as soon as in the tank it can shift significantly. CO2 in your home will have the biggest impact on pH most of the time.

Thanks for the reply. I do understand the effects of co2 on ph. I have a 20lb tank hooked up to my planted fresh water tank. Also the effect of plant growth on the ph. In fresh water the kh is a buffer that restricts the change, low kh easy change, high kh slow or hard to change. The higher kh of salt water doesn't hold the ph?

 

[Joel j]

There are many salt mixes out there and they all have different targets for dKh, calcium, magnesium, etc. freshly mixed saltwater normally mixes to a ph of 8.3 but as soon as in the tank it can shift significantly. CO2 in your home will have the biggest impact on pH most of the time.

Also in fresh water we use substraight to buffer the ph since we have low kh. Is there substraight for salt water for the same purpose? Crushed coral perhaps?

 

[Randy Holmes-Farley]

Any salt mx you use will have all you need.

The final pH depends only on alkalinity and the CO2 level that you aerate the new salt water with. It's not a function of the salt mix, aside from how the alk varies.

No, substrate is not generally useful for alk or pH buffering since it cannot dissolve in seawater at normal pH and alk.