a question of SG

[terryansimon]

okay. I have a very new tank. slightly over a week old in fact. now the tank is filled with salt water of which its SG is about 1.011. don't worry. no livestock in there as yet. liverocks should be coming by tonight.

now. when the liverocks come. I intend to remove say....1/4 of the water to cater for water being displaced when I add the liverocks in. then after that, top up whatever amount of water is needed to top up

question now is this

1) the rocks. I mean it wouldn't explode or die on me if the SG is at 1.013 right? I know its a bit low, but me and my friend were thinking that we could take the time for rock addition as a time of water change as well. we added in salt water and all so that when the addition of livestock goes in, it goes straight into salted water and not freshwater.

2) when I re-top up the water, do topup tank/compartment/container, do I fill up until to the recommended SG of 1.021-1.024 or something? or do I make it equal to the SG of the main tank itself, which is 1.013 after that, when I add it in, how do I equalise the SG in the main tank itself?

I know it sounds a bit complicated. if you're still confused, you can PM me and I'll pass you my handphone number and you can call me. (=

[bawater]

Its simple

adjust your salinity now, before the rocks go in.

raise the level to abt 1.021-1.023 for tank temperatures of 28c or above(this will allow you a 0.002 to 0.005 buffer in salinity due to evaporation). The range of salinity is safe between 1.021-1.026(i prefer 1.023-1.026)

All u need to do is take out some tank water and mix in half a cup of salt with that water in a container then pour it back. Check salinity everytime u mix it back, adjust untill u reach the 1.021-1.023 range.

Once the rocks go in, there will be die offs and your cycle will start. This will also happen if u stay at the current 1.011 but when u raise salinity just before fishes go in...u may get another batch of die offs(from dying bacteria due to the huge change in salinity) which will raise ammonia & nitrite levels...causing additional stress to the already stressed new fishes and so forth it goes.

So once u have got your salinity correct(the earlier the better)- just top up with freshwater to maintain at that salinity.

Playing with low salinity will work more for fish only tanks(but even so- some fishes are less tolerant than others),

corals are not that tolerant.

[terryansimon]

but bawater...

wouldn't the equalisation of SG take a while? the way you phrase it, its like, you can read the difference of SG instantaeneously. either that or I misquoted you. =\

so just to confirm. remove my 1.011 water into say.. a 2ft spare tank I have. add water until it becomes 1.021. then add back into main tank. wait for a while for the water to circulate, retest SG and repeat if need be.

then when I remove the water to cater for displacement, do I add back water with SG matching the main tank?

sorry if I sound like a noob. doing this for the first time. =\

[bawater]

If the salt is properly dissolved, you can take a reading instantly. or you could give it half to 1 hour to settle and take a reading.

i meant- remove a few ltrs of tank water(into a pail or something) and mix salt into it and add back to tank to raise the salinity. You do not need to remove so much.

What you are doing is to make a concentrated brine(salt solution) and adding this to your current volume to increase salinity. Take frequent readings.

*If its an empty tank with no sand- u can actually just add the salt in the tank directly and adjust from there.

when u remove water to add in rocks- this would be where the extra 2ft will come in handy, take out as much as u want and put it in the 2ft then add back what u want till you reach your desired water level in the main tank. There is no need to adjust salinity because you are already at the correct SG.

[terryansimon]

thanks bawater.

I asked another friend for advice as well and he also told me to make a concentrated brine solution before adding it back in.

thanks for the advice! cheers..