Tankerini

Quite a few questions on this;

How do you get the level of S.G you want? i.e if you want it to be 1.201 - 1.204 or at the higher end 1.203-1.206.

Do you buy salt mixes for the level of SG you want or can you buy any salt mix and it will tell you on the back the amount of salt to add for the level of SG you want?

Also is there anything that can affect your SG levels to go up and down in the tank? Or once its at the right level its ok?

What happens to the fishes/corals if it goes out of there recommended range?

Wolfgang8810

Specific Gravity or salinaty can be adjusted by the ratio of salt to water. If your salinaty is high you take some saltwater out of the tank and replace it with freshwater. If your SG is low you can add Saltwater for evaporation top offs and that will raise the Salinaty.

When you buy your salt mix it has instructions on the back telling you how much salt you put in per gallon of water. I believe it is a half cup/gallon.

Evaporation effects the level of your SG. Salt dosent evaporate so when wwater evaporates from your tank it leaves its salt behind which creates a more concentrated amount of salt in the tank.

It depends. How far out of the recommended range are you? I keep my small tank at 1.025 and im keeping every kind of coral successfully. In my 90 gallon tank my SC is at 1.029. A little high but i will bring it down over the next few days.

I hope this helps.

Slug

Agreed.

When it gets to low or to high you will start to notice coral stressing out. SPS polyps closed, zoas shrinking or closed, gsp pulled in. You'll know when your coral is stressed. If its way outside the good range, coral can start dying. Plus your LR will start to die off if the SG is to low and near the freshwater range.

Tankerini

Thanks guys!

I was in my LFS this morning, and read the back of the salt mix instructions so get it now

If your doing a weekly water change, this should keep the sg in the tank quite stable as not much water will evaporate in this time right? (depending on outside influences of course, room temp etc).

Nice bit of info on the corals reaction to SG levels wolfgang Hmmm now you mention it I did notice some of that going on in a tank in the LFS, I better let them know lol. Btw whats gsp?

What salt mix do you two use? They only had Tetra (Which Im thinking is crap!) or seachem.

Wolfgang8810

GSP= Green Star Polyps

yes weekly water changes will be a good idea. However depending on your lights you will have more evaporation. I have a 150 watt Metal halide over ym 24 gallon tank and i lose 2 gallons to evap/week. In my 90 gallon tank I have 300 watts of PC and i lose 3 gallons of water to evap/ week. It depends on surface area really.

If you do get5 some evap and then do a water change before topping off the tank with FW it will gradually boost your SG so weekly FW top offs are a good idea too. :-) Make sure you use either distilled or RO/DI water for top offs. Tap water is bad.

Slug

I use Instant Ocean. Out of Tetra and Seachem i'd personally be inclined to go with Seachem. I like Instant Ocean though.

I do weekly water changes, but i top off everyday. Having a 250w MH over an open top tank and a fan blowing across the water speeds up evaporation a lot. Plus i have a 10gal tank, so i need to stay on top of evaporation or else things can go bad fast. You don't have much slack in a smaller tank.