Serious Problem

You need to get your water parameters in check.

Ideally you want:
  • ammonia 0 ppm
  • nitrite 0 ppm
  • nitrate <20ppm
  • pH between 8.0 and 8.5
  • temperature 77-80 (although this can vary as long as it doesn't swing quickly)
  • SG 1.024-1.026
There are other numbers to check such as calcium, alkalinity, magnesium, etc. but for now you need to concentrate on the top ones. There are many many sources online mentioning how to do this if you don't have access to the books mentioned earlier.

For the QT read this: http://www.aquariacentral.com/forums/blog.php?b=129
 
Does your tap water contain chlorine or chloramines? If so, the use of a tap water conditioner (like Seachem Prime, for example, among others) is a must. Chloramines would also be an ammonia source, so performing water changes with tap water containing chloramines doesn't really do much to reduce ammonia concentrations in a tank.

I have no idea what tap water condtions are like in Pakistan, but RO (reverse osmosis) water at minimum is needed for the majority of us here in the US to be sucessful at reef keeping long term, although many use RO/DI water (reverse osmosis / deionization).
 
Images of my aquarium

I have add the some salt to increase the salinty 10.024 and relocate the power head to produce the good flow and increase the airraton in the aquarium after adding one more air pump of to nosel i think it will also help to increase the Ph any way today i think their is no mortaily and the sistuation seems to be undercontrol and i will also check tomorow the ammonia

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More images

Here i am sending you the more images of my tang and etc well please tell me that what kind of rock it is ? what is the exact nameof butterfuly and what is the name of tang i want to confirm it and is it seems any other change to made if yes please let me know

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If you want them to eat the lettuce you'll need to wilt it first, you can do this by putting it briefly in boiling water.

It looks like some of the rock are old coral skeletons but not sure about the rest. Do you have a mechanical filter on the tank because there isn't enough rock to act as a biological filter and none of it looks to have visible life.

Did you add the salt to water and let it sit for a bit before adding the SW to the tank? Or did you add the salt directly to the tank? What brand of test kits do you use over there and is the SG number reading 1.024 or is 10.024 a unit of measurement that might not be used in the US?

Curious why your water level has dropped so low.

I'm guessing the butterfly is a Chaetodon collare also known as a Pakistan Butteflyfish. Beautiful fish and I think the only caution with them other than not housing them with sessile inverts is feeding them often enough.

I see your clownfish but not your tang. And you should be able to find the anemone with that little rock although I'm guessing it is now gone.
 
Thanks

Okay for lettuce i will wilt it firt to put over here can you tell me that how long i can boil it in hot water i think 1 min is okay or less then this ?

Yes one is skelton of brain coral and the other is i think sea fan skelton and i repaste the image of live rock with this message

'''I think the only caution with them other than not housing them with sessile inverts is feeding them often enough.""

Please explain the above sentence a little more so that i have a clear idea what you want to say.

Well for the salinty i am using two hydrometer one is coralife and the other is make of germeny a glass they both are giving me the same reading and sorry i mistype its 1.024

For amonia test kit i have checked with the hanaa instruments which is made in italy

I hav one canister filter and undergravel filter and please explain me what is the "" mechnical filter ""

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Just boil the lettuce until it gets limp and wilted looking. You don't want it crunchy. A minute is probably fine. I don't do this with lettuce for my tank but I've done it with other veggies for cooking at home.

For the butterfly you have, read this for a starter: http://liveaquaria.com/product/prod_Display.cfm?pCatId=268

1.024 is good, just make sure you are premixing the water and not adding the salt directly to the water in the tank.

The filters you have are both mechanical filters, although the undergravel one has fallen in popularity over the years.
 
The fish on the right on the last pic looks like a kole yellow eyed tang
 
Yes i add salt first mixing in the conatiner and then i put a airstone for hour and after that i pour slowly into my aquarium infront of the power head by this way i increase the salinity
 
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