Brackish Water Mixing Part 3

[mrgreen]

That makes sense. Thanks.

[Markgilst]

What about 25% waterchanges? Will this apply to that as well?

[Dadof4]

If you are doing 25% water changes and want to go up by .002 you can double the number in red. 1.004 becomes 1.008 for example. If you are in the process of raising the SG and only want to do 25% you can just do 25% with the concentrations listed and you will go up by .001 per water change.

[Markgilst]

What if after I'm done with acclimating? What would the specific gravity of the mix have to be after every 25% water change?

[Dadof4]

Once you reach the desired SG goal you just do your water changes with water that matches the current SG.

[KorrepZ]

Something worth mentioning is that the water you replaces needs to be the same temperature as the tank. As the density of water changes along with the temperature

[By_a_coo]

I wonder how much difference in salinity bacteria can stand?

Because when you jump from 1.000 to 1.002 at 25°C you change the salinity from 0g/L to 4,9g/L, that's a big variation, am I right? But, when you start to change the SG every .002, you have a variation of 2.6-2.7 g/L.

So... if the bacteria can hold a variation of 4,9g/L (when you change 1.000 to 1.002), then we could change the SG from 1.002 to 1.005 because the salinity variation would be only 4g/L.

I hope I was unmistakable.

[RTR]

Believe it or not, the bacteria are not uniformly sensitive across the specific gravity range from FW to SW. There is a transition range in which both the marine and freshwater forms can and do co-exist. In that range, the changes need to be very slow with routine ammonia monitoring to allow time for the marine specie to multiply to carry the load.

Without looking it up, I believe that the range is somewhere on the order of 1,007 or 1.0088 - 1/012. Outside that area, things are not so critical for the support bacteria, but the livestock still needs to be considered and moved up slowly.

HTH

[By_a_coo]

Thanks a lot in clarifying my question!

Then the dangerous change lies between 1.007-1012? Is it between these values where we should pay more attention to ammonia and nitrite spikes?

Cheers

[RTR]

You got it. That is for the beneficial bacteria. Other systems will have different critical or transition zones, but the good bugs are the thing that is the most critical other than the display fish or invert that is being taken up to higher salinity.