Sg Values

[jeasko]

OK here we go

Have had the tank since April 07 and has been going well have been consistently doing water changes every week checking all the different levels (SG Nitrate. Nitrite, PH, KH, Temp, alkalinity and amonia) and all ok however over the last month I have lost my green polyp basically it has shrunk to non existent and now the polyps on the soft coral are not opening which is really starting to worry me, the only thing I can think of is that my sg is to high at 1.025 - 1.026 which I was led to believe was an exceptable level from my LFS however reading else where this could be to high, the tank has a finger coral 2 x soft pussey corals and a cauliflower coral which are all doing fine although a recent toadstoll coral has yet to fully open as it is shedding which shouldnt be a problem.

If anyone can throw any ideas in what could be wrong I would be greatful

The tank is 150ltr with 2 x t5 marine white lamps and 2 x t8 blues
about 11- 12 kg LR (more to be added at a later date)
2x powerheads (over the min suggested) creating a circular flow
external canister filter
a v2 400 skimmer
and various critters/clean up crew and fish

 

[Mr Flagfin]

we were always lead to believe that a lower SG is far less stressful for tank inhabitants.
10 years ago, everyone said tanks had to be 1.025-1.026.
Not so nowadays.
We keep all our Marine tanks except the FOWLR at 1.022-1.023. Soft corals love it.
I am not saying that this is your answer, but it may help.
It is all just my opinion, there are lots of more experienced keepers out there who I am sure will chip in.

 

[jeasko]

we were always lead to believe that a lower SG is far less stressful for tank inhabitants.
10 years ago, everyone said tanks had to be 1.025-1.026.
Not so nowadays.
We keep all our Marine tanks except the FOWLR at 1.022-1.023. Soft corals love it.
I am not saying that this is your answer, but it may help.
It is all just my opinion, there are lots of more experienced keepers out there who I am sure will chip in.

I Think it confirms my suspicion that i need to lower the SG so looks like i will need to do some adjusting over the next few days/week

 

[Musho3210]

we were always lead to believe that a lower SG is far less stressful for tank inhabitants.
10 years ago, everyone said tanks had to be 1.025-1.026.
Not so nowadays.
We keep all our Marine tanks except the FOWLR at 1.022-1.023. Soft corals love it.
I am not saying that this is your answer, but it may help.
It is all just my opinion, there are lots of more experienced keepers out there who I am sure will chip in.

hmm, i still hear people saying .24-.27 is best since that is NSW. I havent heard of people recommending .22-.23 for reef tanks but then again, these people are normally hard coral keepers.

 

[andywg]

1.022-1.023 is lower than most of the oceans in the world will be.

Keeping a lower SG may be a help to osmoregualtory organisms like fish, but will not be a great benefit to osmoconformiwsts such as corals which have evolved over millenia to live in water around 35ppt salinity, around 1.025-1.026 IIRC). I would prefer to keep my water as close to the nature the animals are used to as possible. 1.018 and above is usually suggested for FOWLR tanks and the like.

Also, I have read in Dr Shimek's literature that polyp extension is not always a good indicator for how well a coral is doing.

Things to look at are the current (cicular flow is less good than disruptive chaotic flow) and also the coral's placement in the flow. I know that my soft corals did very badly once I upped the turnover to start on hard corals.

 

[n3ont3tra]

Do you have a hydrometer? I've heard they start to drift over time... If you have a refractometer, how did you callibrate it?

 

[jeasko]

Do you have a hydrometer? I've heard they start to drift over time... If you have a refractometer, how did you callibrate it?

I use a hydrometer which has been checked agains a sample of LFS water so the hydrometer is ok may have to look at more disruptive flow as oppose to circular am really starting to worry about my toadstool coral as that hasn't opened since i got it (although it looks like its been shedding), all my readings are fine.

calcium = 400-420
alkaline = normal
ph = 8 (just done a water change and need to add buffer)
kh = 10
amonia = 0
nitrate = 0
nitrite =0 (couldnt be sure of colour so may show a trace but less than 0.025)
SG = 1.024

not that much more i can test that could have changed!

So if anyone has got any more suggestions i would be greatful

 

[Musho3210]

dont add a buffer, it would be great if you didnt add anything as long as you did weekly 10-15% water changes and its not a super acropora garden or anything like that. What test kit are you using?

 

[jeasko]

dont add a buffer, it would be great if you didnt add anything as long as you did weekly 10-15% water changes and its not a super acropora garden or anything like that. What test kit are you using?

I originally went down the route of only doing water changes only to fine out a few months ago that my kh was down to 6 which was a huge worry as 5 and below would almost certainly lead to a crash in kh so went down the route of adding basics such as calcium strontium and iodide the test kits vary from red sea to api and sera.

 

[Musho3210]

well, just as a heads up, my API tests always showed low for me, i dumped large amounts of calcium, kalkwasser (dripped in) buffer etc, still showed up low, tank crashed, lost about 50 dollars, 50 dolalrs wasnt much but that was because not much was spent on it in the first place. I dont test anymore.

 

[SkiFletch]

To be honest, I wouldn't trust the hydrometer... I would do two things. First, bring a sample of YOUR water into the LFS and have them test it with their measuring device. Second, create your own calibration/verification solution and check your own hydrometer that way. Check the realm of knowledge sticky page 2, I posted a link to a DIY verification standard.

Edit: One other comment, how closely have you observed for flatworms, crabs, microinvertebrates, etc that may be damaging your corals?